tag:theconversation.com,2011:/us/topics/sand-34109/articlesSand – The Conversation2024-03-28T18:54:36Ztag:theconversation.com,2011:article/2266802024-03-28T18:54:36Z2024-03-28T18:54:36ZI’ve studied sand dunes for 40 years – here’s what people find most surprising<figure><img src="https://images.theconversation.com/files/585053/original/file-20240328-20-b9wltj.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C7348%2C4131&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sand dunes in Mongolia's Gobi Desert can stretch for 100km.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/sand-dunes-gobi-desert-mongolia-1042829308">mr.wijannarongk kunchit</a></span></figcaption></figure><p>The <a href="https://theconversation.com/uk/topics/dune-43718">Dune films</a> remind us of just how beautiful, mysterious, expansive and changeable sand dunes can be. For centuries these wonderful landforms have filled humans with awe – and in some cases fear and foreboding – because of the apparent remoteness and risks associated with the deserts they are synonymous with. </p>
<p>That’s what first attracted me to research deserts and dunes more than 40 years ago, and I have been investigating them ever since. Here are five things I have learned that may surprise you:</p>
<h2>Not all dunes are made of sand</h2>
<p>Ash, snow and even gypsum can all build dunes. Dunes develop when small particles are mobilised on bare dry surfaces by a moderate wind, accumulating where movement is slowed down by an obstacle or a surface undulation. Where the wind deposits the particles they can create a small mound against which other particles in turn accumulate, leading eventually to a dune. </p>
<p>“Sand” is not really a material – it is a size of particle, somewhere between 0.06mm and 2mm diameter. Dunes in deserts and at the coast are primarily formed of quartz and feldspar grains, the most common minerals on earth. </p>
<p>But in volcanic regions, such as the interior of Iceland, dunes can be formed of ash, while in the centre of Antarctica, the driest and windiest continental earth, dunes can form from ice crystals and snow. In New Mexico, US, the very soft and bright mineral gypsum forms dunes – appropriately the place is called White Sands.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/585055/original/file-20240328-16-ielofy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Man walks on white dunes, mountains in background" src="https://images.theconversation.com/files/585055/original/file-20240328-16-ielofy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/585055/original/file-20240328-16-ielofy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/585055/original/file-20240328-16-ielofy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/585055/original/file-20240328-16-ielofy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/585055/original/file-20240328-16-ielofy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/585055/original/file-20240328-16-ielofy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/585055/original/file-20240328-16-ielofy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The gypsum dunes of White Sands, New Mexico.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/white-sands-national-monument-new-mexico-1065474704">sunsinger / shutterstock</a></span>
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<h2>Dunes can record a history of climate changes</h2>
<p>Sand dunes might seem soft and changeable, but below their active surface there often lies older sand that tells a story of long-term development. </p>
<p>Dune shape is affected by how changeable wind direction is through the year: some dunes, such as crescent-shaped <a href="https://www.sciencedirect.com/science/article/pii/S1875963719302290">barchan dunes</a>, roll forward under fairly consistent winds, with the sand turning over on a regular basis. Others, such as linear and star dunes, develop where wind directions are more variable, piling sand up to thicknesses of tens and even hundreds of metres. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/585062/original/file-20240328-20-5hfp7p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Sand dune from the air" src="https://images.theconversation.com/files/585062/original/file-20240328-20-5hfp7p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/585062/original/file-20240328-20-5hfp7p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/585062/original/file-20240328-20-5hfp7p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/585062/original/file-20240328-20-5hfp7p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/585062/original/file-20240328-20-5hfp7p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/585062/original/file-20240328-20-5hfp7p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/585062/original/file-20240328-20-5hfp7p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Star dunes, like these in Namibia, have three or more ‘arms’ as the wind comes from several directions.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/23027589@N06/33879129024/">Christophe André / flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
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<p>Using a technique called <a href="https://www.sciencedirect.com/science/article/pii/S027737911300156X">luminescence dating</a>, we can measure how long dune sand has been hidden from sunlight, identifying periods when dunes even stopped forming and soils, now themselves buried under more sand, developed on dune surfaces under wetter climates. </p>
<p>In Arabia’s Rub’ al Khali desert, for example, giant linear sand dunes have formed in several dry periods during the <a href="https://www.sciencedirect.com/science/article/pii/S1040618212033812">past 130,000 years</a>. The dunes may even be much older, as it hasn’t yet been possible to drill all the way through to the base and establish the whole accumulation history.</p>
<h2>Only a fifth of deserts are covered by sand dunes</h2>
<p>Only about a fifth of all desert areas have the right conditions to form dunes: a supply of fine loose sediment, enough wind energy and the absence of protective vegetation. Other common desert landscape features include mountains, rock slopes, gravel surfaces and dry lake beds.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/585065/original/file-20240328-22-te593w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Sand dunes on the coast" src="https://images.theconversation.com/files/585065/original/file-20240328-22-te593w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/585065/original/file-20240328-22-te593w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/585065/original/file-20240328-22-te593w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/585065/original/file-20240328-22-te593w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/585065/original/file-20240328-22-te593w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/585065/original/file-20240328-22-te593w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/585065/original/file-20240328-22-te593w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sand dunes can be enormous – the largest are as tall as skyscrapers.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/sand-dunes-on-atlantic-coast-near-2257206993">imageBROKER.com</a></span>
</figcaption>
</figure>
<p>Yet we can go beyond today’s deserts and find evidence of more widespread dune landscapes, for example underneath the grass and woodlands of some of Africa‘s savanna regions such as the <a href="https://www.sciencedirect.com/science/article/pii/S1040618213007088">Kalahari</a> and even under tropical rainforests in parts of <a href="https://www.sciencedirect.com/science/article/pii/S1040618214004522">South America</a>. These dunes testify to different patterns of deserts and climate in the past.</p>
<h2>Scotland’s ancient dunes changed history</h2>
<p>In the 1780s, the Scottish geologist James Hutton realised that the well-bedded and distinctive red sandstones at Siccar Point on Scotland’s eastern coast were in fact the preserved remains of <a href="https://www.geolsoc.org.uk/GeositesSiccarPoint">ancient desert sand dunes</a>. At this location the Devonian old red sandstone, as it is now known, abruptly overlies fine grey mudstones. </p>
<p>Hutton realised that a considerable period of time – we now know it to be over 65 million years – must have elapsed between the grey rocks being laid down, smoothed flat by erosion, and the red sands being deposited on top. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/585057/original/file-20240328-18-9kiyjl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Some rocks" src="https://images.theconversation.com/files/585057/original/file-20240328-18-9kiyjl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/585057/original/file-20240328-18-9kiyjl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=394&fit=crop&dpr=1 600w, https://images.theconversation.com/files/585057/original/file-20240328-18-9kiyjl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=394&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/585057/original/file-20240328-18-9kiyjl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=394&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/585057/original/file-20240328-18-9kiyjl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=496&fit=crop&dpr=1 754w, https://images.theconversation.com/files/585057/original/file-20240328-18-9kiyjl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=496&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/585057/original/file-20240328-18-9kiyjl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=496&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Siccar Point’s red rocks were formed in a desert.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/james-huttons-famous-angular-unconformity-siccar-490865605">Mark Godden / shutterstock</a></span>
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<p>His careful theorising established the <a href="https://www.amnh.org/learn-teach/curriculum-collections/earth-inside-and-out/james-hutton">foundations of modern geology</a> and our understanding that the earth was much older than the history that had been calculated from biblical texts. Further developments in the 20th century enabled us to explain why rocks formed under desert conditions are found in the unlikely context of Scotland – we now know it’s due to movements of the earth’s crust, or plate tectonics.</p>
<h2>Coastal dunes defend against storms</h2>
<p>Sand dunes fringe large tracts of the world’s coastlines, built from wind-blown sand derived from the drying intertidal beach zone and trapped by onshore vegetation. While only <a href="https://data.jncc.gov.uk/data/73b03252-f004-4072-bed3-9fc53731256b/sand-dune-inventory-of-Europe-1991.pdf">7% of the British coastline</a> has dunes, 40% of Australia’s and 60% of Portugal’s are fronted by dunes.</p>
<p>These dunes play a vital role in protecting low-lying land from tidal surges and storms. Yet in some areas human recreation and sand extraction for building has degraded the dunes by damaging stabilising vegetation and creating blow-outs, with sea level rise adding a further risk.</p><img src="https://counter.theconversation.com/content/226680/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Thomas receives funding from NERC and The Leverhulme Trust. He is also affiliated with The University of Witwatersrand, South Africa. </span></em></p>Dunes can preserve a record of historic climate changes and shifting continents.David Thomas, Professor of Geography, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2241522024-03-25T12:39:22Z2024-03-25T12:39:22ZWhat is dirt? There’s a whole wriggling world alive in the ground beneath our feet, as a soil scientist explains<figure><img src="https://images.theconversation.com/files/582688/original/file-20240318-24-77z9su.jpg?ixlib=rb-1.1.0&rect=0%2C9%2C3110%2C2057&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Dig into soil and you'll find rock dust but also thousands of living species.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/little-childs-hands-digging-in-the-mud-royalty-free-image/619539728">ChristinLola/iStock/Getty Images Plus</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption"></span>
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<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
<hr>
<blockquote>
<p><strong>What is dirt? – Belle and Ryatt, ages 7 and 5, Keystone, South Dakota</strong></p>
</blockquote>
<hr>
<p>When you think about dirt, you’re probably picturing soil. There’s so much more going on under our feet than the rock dust, or “dirt,” that gets on your pants.</p>
<p>When <a href="https://arts-sciences.und.edu/academics/biology/brian-darby/index.html">I began studying soil</a>, I was amazed at how much of it is actually alive. Soil is teeming with life, and not just the earthworms that you see on rainy days.</p>
<p>Keeping this vibrant world healthy is <a href="https://www.youtube.com/watch?v=Qas9tPQKd8w">crucial for food, forests and flowers to grow</a> and for the animals that live in the ground to thrive. Here’s a closer look at what’s down there and how it all works together.</p>
<figure class="align-center ">
<img alt="Cupped hands holds soil against a dark background with a tendril of plant root dangling through the fingers." src="https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Soil is a vibrant ecosystem.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/bokeh-photography-of-person-carrying-soil-jin4W1HqgL4">Gabriel Jimenez via Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>The rocky part of soils</h2>
<p>If you scoop up a handful of dry soil, the basic dirt that you feel in your hand is actually very small pieces of <a href="https://passel2.unl.edu/view/lesson/c62dc027ae56/1">weathered rock</a>. These tiny bits eroded from larger rocks over millions of years.</p>
<p>The <a href="https://www.soils4teachers.org/physical-properties/">balance of these particles</a> is important for how well soil can hold water and nutrients that plants need to thrive. </p>
<p>For example, <a href="https://www.masterclass.com/articles/sandy-soil-guide">sandy soil</a> has larger rock grains, so it will be loose and can easily wash away. It won’t hold very much water. <a href="https://www.thespruce.com/understanding-and-improving-clay-soil-2539857">Soil with mostly clay</a> is finer and more compact, making it difficult for plants to access its moisture. In between the two in size is <a href="https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/what-is-silt.htm">silt, a mix of rock dust and minerals</a> often found in fertile flood plains.</p>
<p>Some of the most productive soils have a good balance of sand, clay and silt. <a href="https://www.masterclass.com/articles/how-to-create-loam-soil-for-your-garden">That combination</a>, along with the remnants of plants and animals that have died, helps the soil to retain water, allows plants to access that water and minimizes erosion from wind or rain.</p>
<figure class="align-center ">
<img alt="Three tipped over pots spill different types of soil – sandy is heavier grain, clay is finer grain and thicker, and loamy is darker." src="https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=371&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=371&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=371&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=467&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=467&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=467&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Loamy soil, ideal for gardens, is a mix of sand, clay and silt.</span>
<span class="attribution"><a class="source" href="https://www.nesdis.noaa.gov/learn-about-soil-types">NOAA</a></span>
</figcaption>
</figure>
<h2>The wriggling, munching parts of soil</h2>
<p>Among all those rock particles is a <a href="https://doi.org/10.3390/app10113717">whole world of living things</a>, each busy doing its job.</p>
<p>To get a sense of just how many creatures are there, picture this: The zoo in Omaha, Nebraska, boasts <a href="https://www.omahazoo.com/">over 1,000 animal species</a>. But if you scooped up a small spoonful of soil in your backyard, it would likely contain <a href="https://www.ceh.ac.uk/our-science/case-studies/case-study-why-do-soil-microbes-matter">at least 10,000 species</a> and around a billion living microscopic cells.</p>
<p>Most of those species are <a href="https://www.westernsydney.edu.au/newscentre/news_centre/story_archive/2018/first_soil_atlas">still largely a mystery</a>. Scientists don’t know much about them or what they do in soil. In fact, most species in soil don’t even have a formal scientific name. But each plays some kind of role in the vast soil ecosystem, including generating the <a href="https://www.aces.edu/blog/topics/farming/essential-plant-elements/">nutrients that plants need to grow</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two centipede-like creatures caught on camera immediately after a rock is lifted." src="https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=439&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=439&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=439&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=552&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=552&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=552&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Lifting a rock reveals a symphylan, or garden centipede, left, and a poduromorph, or plump springtail, munching through the soil.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Symphylan_%26_poduromorph_springtail_(3406419924).jpg">Marshal Hedin via Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Imagine a leaf falling from a tree in late autumn.</p>
<p>Inside that leaf are a lot of nutrients that plants need, such as nitrogen, potassium and phosphorus. There is also a lot of <a href="https://scied.ucar.edu/learning-zone/earth-system/biogeochemical-cycles">carbon in that leaf</a>, which holds energy that can be used by other organisms such as bacteria and fungi.</p>
<p>The leaf itself is too large for a plant to take up through its roots, of course. But that leaf can be broken down into smaller and smaller pieces. This process of breaking down plant and animal tissue is <a href="https://youtu.be/IBvKKMzXYtY?feature=shared">known as decomposition</a>.</p>
<p>When the leaf first falls to the ground, <a href="https://doi.org/10.3390%2Finsects11010054">arthropods</a> – such as insects, mites and <a href="https://www.chaosofdelight.org/collembola-springtails">collembolans</a> – break the leaf down into smaller chunks by shredding the tissue. Then, an <a href="https://youtu.be/n3wsUYg3XV0?feature=shared">earthworm might come along</a> and eat one of the smaller chunks and break it down even more in <a href="https://www.pbs.org/video/how-do-worms-turn-garbage-into-compost-jwj6cm/">its digestive tract</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/2Pa1FwmKZcQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">PBS explores how earthworms help turn dead plants into fertile soil.</span></figcaption>
</figure>
<p>Now the broken-up leaf is small enough for microbes to come in. <a href="https://ohioline.osu.edu/factsheet/anr-36">Bacteria</a> and <a href="https://ohioline.osu.edu/factsheet/anr-37">fungi secrete enzymes</a> into the soil that further break down organic material into even smaller pieces. If enough microbes are active, eventually this organic material will be broken down enough that it can dissolve in water and be taken up by plants that need it.</p>
<p>To aid in this process, there are many small animals, such as <a href="https://www.canr.msu.edu/news/are_soil_nematodes_beneficial_or_harmful">nematodes</a> and <a href="https://www.livingsoil.net/protozoa">amoebae</a>, that consume bacteria and fungi. There are also predatory nematodes that feed on other nematodes to make sure they don’t become too abundant, so everything remains in balance as much as possible. </p>
<p>It’s quite a complicated food web of interacting species in a delicate balance.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/IBvKKMzXYtY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A time-lapse video filmed about 4 inches underground shows a leaf decomposing over 21 days in July. At the end, radish roots make their way down into the soil. Video by Josh Williams.</span></figcaption>
</figure>
<p>While some fungi and bacteria <a href="https://www.growingagreenerworld.com/bacteria-fungus-and-viruses-an-overview/">can harm plants</a>, there are many species that are considered beneficial. In fact, they <a href="https://www.nrcs.usda.gov/conservation-basics/natural-resource-concerns/soils/soil-health">may be the key</a> to figuring out how to grow enough crops to feed everyone without degrading and overburdening the soil.</p>
<h2>Figuring out your soil type</h2>
<p>Scientists have named <a href="https://www.nrcs.usda.gov/resources/education-and-teaching-materials/soil-facts">over 20,000 different types</a> of unique soils. If you’re curious about the <a href="https://www.nesdis.noaa.gov/learn-about-soil-types">soil and dirt in your area</a>, the University of California, Davis has a <a href="https://casoilresource.lawr.ucdavis.edu/gmap/">website where you can learn</a> more about local soils and their chemical and physical attributes.</p>
<p><a href="https://www.farmers.gov/conservation/soil-health">Caring for soil</a> to promote its living creatures’ benefits and minimize their harm takes work, but it’s essential for keeping the land healthy and growing food for the future.</p>
<hr>
<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>. Please tell us your name, age and the city where you live.</em></p>
<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/224152/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brian Darby receives funding from the United States Department of Agriculture. </span></em></p>Rock dust is only part of the story of soil. Living creatures, many of them too tiny to see, keep that soil healthy for growing everything from food to forests.Brian Darby, Associate Professor of Biology, University of North DakotaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2143072024-01-04T20:01:53Z2024-01-04T20:01:53ZBecome a beach scientist this summer and help monitor changing coastlines<figure><img src="https://images.theconversation.com/files/565647/original/file-20231213-17-zlgqzp.jpg?ixlib=rb-1.1.0&rect=35%2C11%2C3958%2C2257&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">CoastSnap</span></span></figcaption></figure><p>When you arrive at your favourite beach these summer holidays, you may notice something different about the coast. </p>
<p>With the triple-dip La Niña now <a href="https://media.bom.gov.au/releases/1205/the-bureau-forecasts-an-unusually-warm-summer/">making way for El Niño</a>, our beaches have been through a rollercoaster ride. Some beaches have been completely stripped of sand, while others have grown very wide. </p>
<p>In the past, such changes went mostly unrecorded. However, thanks to a project <a href="https://www.coastsnap.com/">known as CoastSnap</a>, coastal data is now being collected like never before. Using designated camera cradles installed at beach viewpoints, CoastSnap uses community snapshots taken on smartphones to track beach change. </p>
<p>Almost <a href="https://www.spotteron.com/coastsnap/">50,000 photos</a> have been collected so far. They have revealed a varying picture in recent years: from <a href="https://www.abc.net.au/news/2020-02-12/tropical-cyclone-uesi-bring-dangerous-conditions-nsw-coast/11955628">dramatic beach loss during La Niña storms three years ago</a>, to <a href="https://www.smh.com.au/environment/climate-change/the-sydney-beach-that-s-grown-by-59-metres-since-last-summer-20230921-p5e6id.html">60 metres of beach growth in recent months</a>. So with smartphones as commonplace as towels and sunscreen in the beach bag, why not add coastal data collection to your list of holiday activities this summer?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/563079/original/file-20231203-29-n4laod.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="CoastSnap stainless steel camera cradle with smartphone placed in it, overlooking Manly beach" src="https://images.theconversation.com/files/563079/original/file-20231203-29-n4laod.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/563079/original/file-20231203-29-n4laod.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563079/original/file-20231203-29-n4laod.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563079/original/file-20231203-29-n4laod.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563079/original/file-20231203-29-n4laod.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563079/original/file-20231203-29-n4laod.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563079/original/file-20231203-29-n4laod.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A CoastSnap community beach monitoring station at Manly Beach in Sydney, Australia.</span>
<span class="attribution"><span class="source">Larry Paice</span></span>
</figcaption>
</figure>
<h2>Turning beach snaps into scientific data</h2>
<p>Through CoastSnap, we installed a network of stainless-steel camera cradles along coastal trails all around the world. These camera cradles are positioned at a perfect vantage point for tracking changes to the coast – whether it be due to rising sea levels, extreme storms or other factors.</p>
<p>All you need to do is place your camera in the cradle, take a photo and upload it using the QR code at the station. Because the position and angle of the photo is always the same, over time these snaps reveal how the beach is changing.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/millions-of-satellite-images-reveal-how-beaches-around-the-pacific-vanish-or-replenish-in-el-nino-and-la-nina-years-198505">Millions of satellite images reveal how beaches around the Pacific vanish or replenish in El Niño and La Niña years</a>
</strong>
</em>
</p>
<hr>
<p>As well as being a powerful visual record, <a href="https://www.sciencedirect.com/science/article/pii/S0278434322001492">sophisticated algorithms</a> turn each photo into miniature satellite images that are used to precisely measure shoreline position. This is done using a <a href="https://en.wikipedia.org/wiki/Photogrammetry">process known as photogrammetry</a>, in which pixels in the image are rearranged as though they had been taken from space. </p>
<p>This aerial view enables beach change to be easily measured. Also, since the exact time of photo capture is recorded, the effects of tides as they vary throughout the day can be accounted for.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/563240/original/file-20231204-17-8678xw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="CoastSnap photo of beach (left) and equivalent photo converted to an aerial photo with a red line to mark out the shoreline" src="https://images.theconversation.com/files/563240/original/file-20231204-17-8678xw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/563240/original/file-20231204-17-8678xw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=317&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563240/original/file-20231204-17-8678xw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=317&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563240/original/file-20231204-17-8678xw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=317&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563240/original/file-20231204-17-8678xw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=398&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563240/original/file-20231204-17-8678xw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=398&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563240/original/file-20231204-17-8678xw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=398&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">CoastSnap photos are converted to a miniature satellite image using a process known as photogrammetry.</span>
<span class="attribution"><span class="source">Mitchell Harley</span></span>
</figcaption>
</figure>
<h2>From local to global: a network of community beach monitoring</h2>
<p>From its beginnings on the Northern Beaches of Sydney in 2017, new CoastSnap stations have been rolled out all around the world. We now have more than 350 CoastSnap stations in 31 countries and across five continents. </p>
<p>This makes it the largest coordinated network of coastal monitoring worldwide – and all the data is collected by the community.</p>
<p>In Ghana, West Africa, students from local schools are using CoastSnap to <a href="https://theconversation.com/ghanas-fishing-industry-has-a-golden-seaweed-problem-how-citizen-science-can-help-203007">better understand how the “golden seaweed” sargassum impacts fishing communities</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/like-20-tip-trucks-pouring-sand-on-every-metre-wide-strip-how-extreme-storms-can-replenish-beaches-not-just-erode-them-182039">‘Like 20 tip trucks pouring sand on every metre-wide strip’: how extreme storms can replenish beaches, not just erode them</a>
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</em>
</p>
<hr>
<p>On Prince Edward Island in Canada, CoastSnap captured the <a href="https://www.cbc.ca/news/canada/prince-edward-island/pei-fiona-coastal-climate-change-1.6599408">damage done by Hurricane Fiona last year</a>. The same stations are now being used to track the post-hurricane dune recovery.</p>
<p>In Australia, there are currently 125 CoastSnap stations around the country. This enables a big-picture assessment of the coastal consequences of large-scale weather events. For example, during <a href="https://theconversation.com/the-east-coast-rain-seems-endless-where-on-earth-is-all-the-water-coming-from-178316">last year’s record rainfall in eastern Australia</a>, extreme erosion was observed at CoastSnap stations from Queensland to southern New South Wales. The images reveal scouring by floodwaters was the main cause of beach erosion in many locations, rather than wave action as is usually the case.</p>
<p><div data-react-class="TiktokEmbed" data-react-props="{"url":"https://www.tiktok.com/@coastsnap/video/7192798251588898049"}"></div></p>
<h2>Monitoring the present to plan for the future</h2>
<p>Data on coastal change is crucial for managing coastlines into the future. This is particularly important as sea levels continue to rise, storm tracks shift, and beaches come under increasing pressure from overdevelopment.</p>
<p>With several CoastSnap stations already operating for over six years now, this growing record is beginning to observe longer-term changes to the coast. This data is being fed into numerical models that help coastal researchers predict what the coastline will be like in the coming decades – and plan accordingly.</p>
<p>Smart coastal planning will help buffer climate change impacts. This will go some way to ensure future generations can enjoy the coast like we do today. </p>
<p>So as you head out to the beach this summer, look out for your nearest CoastSnap station and help monitor the coastline – it really is a “snap”!</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/storms-or-sea-level-rise-what-really-causes-beach-erosion-209213">Storms or sea-level rise – what really causes beach erosion?</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/214307/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mitchell Harley receives funding from the Australian Research Council. He is also the New South Wales Chair of the Australian Coastal Society.</span></em></p><p class="fine-print"><em><span>Fred Chaaya works for the University Of New South Wales Water Research Laboratory, which manages the CoastSnap project and network.</span></em></p>With smartphones as commonplace as towels and sunscreen in the beach bag, why not add coastal data collection to your list of holiday activities this summer? Look for the CoastSnap camera cradles.Mitchell Harley, Scientia Senior Lecturer, UNSW SydneyFred Chaaya, Project Engineer, UNSW Water Research LaboratoryLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2156002024-01-02T20:16:14Z2024-01-02T20:16:14ZWhen you sit down to build a sandcastle, take a look around you: the beach is already sculpting<figure><img src="https://images.theconversation.com/files/562331/original/file-20231129-24-7zibnd.jpg?ixlib=rb-1.1.0&rect=0%2C41%2C3988%2C5946&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/brown-rock-on-brown-sand-during-daytime-oG_hQ7nQje0">Thomas Williams/Unsplash</a></span></figcaption></figure><p>Arenicola, or lugworms, make some of the most beautiful structures on the beach. Little piles of wet sand are cast in a swirl from their rear end as part of their feeding cycle. </p>
<p>They are but one of an untold number of other participants in the constant evolution of forms at our water’s edge. Co-contributors include the wind, birds, rain, foliage, foot traffic and detritus, all shaping sand and associated debris into mini peaks and troughs, lines, blobs and tracks. </p>
<p>The forming of grains into what we commonly call a sandcastle on the other hand, speaks to a particularly human intentionality. Centred around the activity of building, these edifices rise and fall through a wild negotiation of the intent of a person and the intent of the materials they work with. </p>
<p>This dynamic and fickle nature of the granular shells, quartz, coral, glass and rock is perhaps its greatest appeal. Accrued since childhood, our knowledge of sand’s properties sits deep within our personal sculptural memory. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/562328/original/file-20231129-21-q1zu3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Piles of tubes made of sand." src="https://images.theconversation.com/files/562328/original/file-20231129-21-q1zu3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/562328/original/file-20231129-21-q1zu3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562328/original/file-20231129-21-q1zu3w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562328/original/file-20231129-21-q1zu3w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562328/original/file-20231129-21-q1zu3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562328/original/file-20231129-21-q1zu3w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562328/original/file-20231129-21-q1zu3w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Lugworms make some of the most beautiful structures on the beach.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>In collaboration with the beach</h2>
<p>Building a sandcastle is a response to the full beach environment as a collaborator. We attune ourselves to the quality of the sand, marvel at the comings and goings of the water and orient our construction for the wind’s abrasive blast. </p>
<p>We are vigilant to dogs’ unintended mark making, and backward running ball catchers who involuntarily progress our work from castle to ruin. Moulds that reproduce their internal structure can be the age-old bucket, or the form can be loosened up using towels, sandals, buckets or a friend’s back … and perhaps said friend can be embedded in the structure if required. </p>
<p>We can include tunnels (that will sadly collapse) and moats and complete our work with a final (for me) infuriating flourish of seaweed and sticks. </p>
<p>No one methodology will explain to the uninitiated how to undertake the making of a sandcastle, and this is how it should be. Adopting an attentive mindset can open the possibilities for this immersive and bodily task.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/my-art-uses-plastic-recovered-from-beaches-around-the-world-to-understand-how-our-consumer-society-is-transforming-the-ocean-187970">My art uses plastic recovered from beaches around the world to understand how our consumer society is transforming the ocean</a>
</strong>
</em>
</p>
<hr>
<h2>Attending to sand</h2>
<p>Particular qualities of sand can be revealed to those who remain aware. Building a sandcastle on a day after the rain can change the material and the way it presents. </p>
<p>Rain falling from the sky onto fine sand creates a crispy layer over the drier sand below. It is the crunchy feeling underfoot for those daily pioneers to the beach who arrive before these fragile structures are trampled underfoot. Rain creates a crust that would be difficult to produce any other way. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/563488/original/file-20231204-25-ys9df3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A beach after rain." src="https://images.theconversation.com/files/563488/original/file-20231204-25-ys9df3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/563488/original/file-20231204-25-ys9df3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563488/original/file-20231204-25-ys9df3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563488/original/file-20231204-25-ys9df3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563488/original/file-20231204-25-ys9df3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563488/original/file-20231204-25-ys9df3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563488/original/file-20231204-25-ys9df3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Rain creates a crust that would be difficult to produce any other way.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>This and other states of sand could be considered on a continuum of material behaviours, from dry to wet, from dispersed to grouped, from fine to coarse, from quartz, through skeleton, to shell, or from a <a href="https://www.sciencelearn.org.nz/resources/1502-non-newtonian-fluids">Newtonian to a non-Newtonian fluid</a>. </p>
<p><a href="https://www.bcsands.com.au/sand_guide">In construction</a> there is sharp sand, fat sand and sand of specific dimensions. The sand at the beach is the sand of that beach, undifferentiated by industrial ecologies and taken at its face value. Sluggish waterlogged mass, or blow away dust structure, compact sand, beige, black or grey – its specific qualities determining the outcome as much as the plan we bring to the task. </p>
<h2>Working against collapse</h2>
<p>Making objects with sand at the beach is a most egalitarian form of art making. Critiques of our constructions are generally of the generous kind. Passersby will applaud the magnitude of our creation, share in the joy as water fills our castle’s moats, and laugh shamelessly when the whole structure collapses. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/563493/original/file-20231204-27-1gzbvs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A sand castle." src="https://images.theconversation.com/files/563493/original/file-20231204-27-1gzbvs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/563493/original/file-20231204-27-1gzbvs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563493/original/file-20231204-27-1gzbvs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563493/original/file-20231204-27-1gzbvs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563493/original/file-20231204-27-1gzbvs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563493/original/file-20231204-27-1gzbvs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563493/original/file-20231204-27-1gzbvs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Making objects with sand at the beach is a most egalitarian form of art making.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Sand workers on the beach can adopt a critical position relative to the way the sand acts and be mesmerised by its characteristics as these present themselves. We can understand that sand slumps in a particular way, and compact it in anticipation. Or we can simply burrow furiously as it falls off in great slabs. Each reflects the personal attitude of the builder; neither is better than the other.</p>
<p>Seagrass, kelp, stones, glass and the egg sacs of moon snails may all present themselves for inclusion in a sandcastle. Driftwood will break through hard sand, create moats, or delineate space; large shells make excellent tools for moving bulk material, although using the body for scooping and compacting, or shoving and dragging, is perhaps the ideal way to engage the senses in the job. Collapse is the thing you work against. </p>
<p>Digging down and water begins to pool, piling the sand high and your castle begins to emerge.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-to-get-the-most-out-of-sand-play-4-tips-from-a-sculptor-195209">How to get the most out of sand play: 4 tips from a sculptor</a>
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</em>
</p>
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<img src="https://counter.theconversation.com/content/215600/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark Friedlander does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Building a sandcastle is a response to the full beach environment as a collaborator.Mark Friedlander, PhD Candidate, Victorian College of the Arts, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2147552023-10-23T07:55:17Z2023-10-23T07:55:17ZVictims of the green energy boom? The Indonesians facing eviction over a China-backed plan to turn their island into a solar panel ‘ecocity’<p>I first visited Rempang island in Summer 2022. Greeting me were lush fields lined with coconut and banana trees, picture-book fishing villages with houses jutting into the water on stilts, and boats carrying people between the dozens of islands that dot the Riau archipelago in western Indonesia. I had made the pleasant, one-hour ferry trip from bustling, glass-and-chrome Singapore. This felt like another world.</p>
<p>My hosts (an environmental lawyer and an indigenous Melayu community organiser) and I had reached Rempang from the economic hub of Riau Islands province: the special manufacturing, trade and logistics zone of <a href="https://www.indonesia.travel/uk/en/destinations/sumatra/batam">Batam</a>. We had gone from Batam to Rempang by crossing one of the six metal bridges that connect the islands of Batam, Rempang and Galang. This network of bridges has turned the islands into an economic zone, now called the Barelang region. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/konflik-rempang-bagaimana-proyek-transisi-energi-yang-didukung-cina-justru-merampas-lahan-rakyat-bagian-1-216178">Konflik Rempang: bagaimana proyek transisi energi yang didukung Cina justru merampas lahan rakyat (bagian 1)</a>
</strong>
</em>
</p>
<hr>
<p>My ongoing research is investigating how the international quest for green energy is reliant on “sacrificial zones” in developing countries. The transition to green energy, far from creating a green new deal for all, is actually reinforcing entrenched inequalities and hierarchies.</p>
<figure class="align-center ">
<img alt="Large suspension bridge" src="https://images.theconversation.com/files/552772/original/file-20231009-19-qgpzcr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/552772/original/file-20231009-19-qgpzcr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/552772/original/file-20231009-19-qgpzcr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/552772/original/file-20231009-19-qgpzcr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/552772/original/file-20231009-19-qgpzcr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/552772/original/file-20231009-19-qgpzcr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/552772/original/file-20231009-19-qgpzcr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Batam Rempang Galang Bridge (Barelang). This bridge connects Batam Island with Rempang Island and Galang Island.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/batam-rempang-galang-bridge-barelang-this-2099136529">Shutterstock/NPCplastik</a></span>
</figcaption>
</figure>
<p>I became interested in Rempang when I saw news reports heralding a renewable energy revolution. Companies from Singapore, Portugal and beyond were <a href="https://www.reuters.com/business/energy/sunseap-build-2-bln-floating-solar-farm-indonesia-worlds-largest-2021-07-22/">signing agreements</a> to build vast floating solar farms in local reservoirs in the Batam region. The plan was that the clean energy produced would be transported from the sunlit western Indonesian islands of Batam, Bulan, and Rempang to energy intensive Singapore via undersea cable.</p>
<p>But on reaching the islands, and visiting the sites named in the news reports, I saw no sign of green energy activity. The waters were placid. There was no solar farm in sight. I shrugged, met friends, ate the freshest possible seafood at a small <a href="https://en.wikipedia.org/wiki/Kelong">Kelong</a> restaurant that was half on land and half in the sea, and went back to Singapore on the ferry. </p>
<h2>‘A state-backed land grab’</h2>
<p>My return a year later could not have been more different. The atmosphere was tense and the roads were lined with armed police. Large military trucks moved ominously on the tar, monitoring the situation. Villagers stood around in clusters, anxious and clutching at straws of information trickling through on WhatsApp and word of mouth about what seemed to be a <a href="https://academic.oup.com/edited-volume/44609/chapter/393367359">state-backed land grab</a>.</p>
<hr>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/288776/original/file-20190820-170910-8bv1s7.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/288776/original/file-20190820-170910-8bv1s7.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/288776/original/file-20190820-170910-8bv1s7.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/288776/original/file-20190820-170910-8bv1s7.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/288776/original/file-20190820-170910-8bv1s7.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/288776/original/file-20190820-170910-8bv1s7.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/288776/original/file-20190820-170910-8bv1s7.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption"></span>
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<p><strong><em>This article is part of Conversation Insights</em></strong>
<br><em>The Insights team generates <a href="https://theconversation.com/uk/topics/insights-series-71218">long-form journalism</a> derived from interdisciplinary research. The team is working with academics from different backgrounds who have been engaged in projects aimed at tackling societal and scientific challenges.</em></p>
<hr>
<p>People were protesting because the 16 villages and 7,500 inhabitants of Rempang are facing eviction, as plans to transform their home into the latest hub for the global green transition gather apace. The Indonesian government and a Chinese-backed business consortium want to <a href="https://time.com/6313609/indonesia-rempang-eco-city-protests-china/">move the entire community</a> to another island and turn their home into a huge solar panel manufacturing centre, solar farm, and “ecocity”.</p>
<p>Videos filmed by residents from sites of protest show armed military and police clashing with the farmers and fishers of Rempang. The videos, some of which have been posted on social media, show people being thrown to the ground, bleeding, apparently roughed up by state forces. There have been many arrests. I regularly hear from friends and acquaintances who tell me that police and government authorities have taken to summoning suspected protestors, examining their phones for incriminating evidence, and looking into their home, work lives and tax affairs. Residents are clear this is “harassment” and “pressure” to give up their land and withdraw from the struggle. </p>
<p>Alongside large and publicised confrontations, the residents of Rempang are resisting the everyday encroachments of the proposed project. In local, spontaneous opposition in affected villages, women, including mothers and grandmothers in veils, have blocked roads, preventing government officials from entering villages to measure their land. Videos show them wailing as armed police approach. In others, young girls and old women can be seen in a semi-conscious state, being taken to hospital after apparent tear gassing.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/03Wx_rxBKXg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
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<p>But how did things move so fast? From April 2023, news had begun to filter in that a well-connected businessman from Jakarta, who reportedly made his money and reputation <a href="https://www.smh.com.au/world/dili-tycoon-deal-triggers-alarm-20090502-aqtj.html">through businesses operated</a> on behalf of the Indonesian military, before turning to <a href="https://www.tatlerasia.com/people/tomy-winata">banking and real estate</a>, was to build a “township” on Rempang.</p>
<p>By August, the better informed in the community had gathered that the planned Rempang project was to be a collaboration between Tomy Winata’s Artha Graha Group, and a Chinese “glass manufacturer”. By September, Winata himself <a href="https://en.tempo.co/read/1775361/tomy-winata-its-just-miscommunication">was granting interviews</a> and talking about his plans for an ecocity. <a href="https://futuresoutheastasia.com/rempang-eco-city/">The project</a> – which has the enthusiastic blessings of the Batam economic zone authorities, the provincial government of Riau Islands, and importantly, the central government in Jakarta – is imminent. </p>
<p>It will displace 16 villages on Rempang island and will cover a mind boggling 17,000 hectares (one square hectare is roughly equivalent to one rugby field). As residents discussed these figures among themselves, they lobbed questions at me: “Why do they need so much land?” and “what will they even do with it?”</p>
<p>An elderly, mild mannered fisherman I spoke to in August, who was trying to organise resistance to what was then still a mysterious investment pushed by Jakarta and China said he was worried about the community being relocated:</p>
<blockquote>
<p>People here have history. Their whole story is in this area. They love this land. They live here. You can make your project here. Welcome. But build it in an empty area. Whatever you do, don’t disturb us. Keep us here, give jobs to our children … When people ask me, where is your village, I say it is Bapke [pseudonym]. Later, what will I say? Our identity will be lost.</p>
</blockquote>
<h2>From trickles of information to violence</h2>
<p>On first learning about the Rempang project, residents petitioned different layers of government, sought meetings, and even went to Jakarta to try and meet officials. Finding them unresponsive, people contemplated taking to the streets.</p>
<p>By mid-August, groups were meeting at local cafes and in the homes of community leaders. They were determined not to give up their land. One member of a group that was congregating in Batam told me “there is a meeting of Melayu youth to plan a protest at Barelang [bridge], and at the mayor’s office [in Batam]. We are here to discuss the situation. We will protest in the coming days”.</p>
<p>By the last week of August, there were demonstrations organised by the community at various locations in Rempang and Batam, and by civil society organisations in Jakarta. Soon, my contacts were talking about “clashes between the community and BP Batam” (<a href="https://bpbatam.go.id/en/profile/background/">the authority in charge</a> of the Batam free trade zone), and larger and larger demonstrations involving not just Rempang residents, but ethnic Melayus from the surrounding islands as well. At these early protests, police forces were present, there was tension, but no violence.</p>
<p>Despite growing opposition, authorities dismissed popular discontent as “<a href="https://www.thejakartapost.com/indonesia/2023/09/14/jokowi-downplays-rempang-riot-as-miscommunication.html">miscommunication</a>”. As reported in the press, increasingly incensed residents began to resort to violence, <a href="https://www.channelnewsasia.com/asia/rempang-eco-city-batam-indonesia-riot-bp-xinyi-3764671?utm_source=flipboard&utm_content=channelnewsasia%2Fmagazine%2FCNA">using rocks and glass bottles</a>. These were desperate measures from increasingly desperate people facing the might of the state.</p>
<figure class="align-center ">
<img alt="Protestors on the streets holding banners." src="https://images.theconversation.com/files/552754/original/file-20231009-21-j7gcb9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/552754/original/file-20231009-21-j7gcb9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/552754/original/file-20231009-21-j7gcb9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/552754/original/file-20231009-21-j7gcb9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/552754/original/file-20231009-21-j7gcb9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/552754/original/file-20231009-21-j7gcb9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/552754/original/file-20231009-21-j7gcb9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Hundreds of people staged a protest against the Rempang ecocity project in central Jakarta on September 20, 2023.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/jakarta-indonesia-september-20-2023-hundreds-2365501927">Shutterstock/KevinHerbian</a></span>
</figcaption>
</figure>
<p><a href="https://www.thejakartapost.com/indonesia/2023/09/17/govt-insists-on-rempang-project-following-visit-by-ministers-police.html">Local</a> and <a href="https://www.aljazeera.com/news/2023/9/15/protests-in-indonesia-as-thousands-face-eviction-for-rempang-eco">international media</a>, which had initially ignored the Rempang issue, was finally <a href="https://time.com/6313609/indonesia-rempang-eco-city-protests-china/">covering it</a> amid escalating “<a href="https://www.thejakartapost.com/indonesia/2023/09/13/police-arrest-43-after-riot-over-china-backed-rempang-city-project.html">rioting</a>” at Rempang.</p>
<p>A Melayu youth messaged me on Whatsapp recently, saying: “I was called to the police station for questioning … I went through the investigation process [for many hours] regarding the case at [location X]. There was a clash between community and authorities which resulted in eight people being sent to prison.”</p>
<h2>Ecocity and mega solar panel production facility</h2>
<p>Meanwhile, preparations for the Rempang development have continued apace. It appears that as early as 2004, the Indonesian company PT Makmur Elok Graha (PT MEG), which is part of the Artha Graha Group, secured permission from the Batam Regional People’s Representative Council to <a href="https://ugm.ac.id/en/news/rempang-conflict-land-disputes-triggered-by-development-project/">develop Rempang</a>. The understanding at the time was for a tourism zone, covering <a href="https://www.aljazeera.com/news/2023/9/27/how-a-china-deal-put-the-homes-of-thousands-of-indonesians-at-risk">5,000 hectares</a>. Existing villages were to be preserved in this plan.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/552962/original/file-20231010-19-c6innt.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A tweet from Amnesty International." src="https://images.theconversation.com/files/552962/original/file-20231010-19-c6innt.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/552962/original/file-20231010-19-c6innt.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=952&fit=crop&dpr=1 600w, https://images.theconversation.com/files/552962/original/file-20231010-19-c6innt.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=952&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/552962/original/file-20231010-19-c6innt.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=952&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/552962/original/file-20231010-19-c6innt.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1196&fit=crop&dpr=1 754w, https://images.theconversation.com/files/552962/original/file-20231010-19-c6innt.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1196&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/552962/original/file-20231010-19-c6innt.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1196&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Amnesty International is trying to draw attention to the islanders’ situation on social media.</span>
<span class="attribution"><a class="source" href="https://twitter.com/amnestyindo/status/1708679798720180432">X</a></span>
</figcaption>
</figure>
<p>Nothing came of the agreement with PT MEG, until 2023. Earlier in 2023, representatives of PT MEG visited houses of notable locals in Rempang and indicated their intention to survey the land. According to one such local businessperson and community leader, the company did not inform him about what they intended to build. However, in a neighbouring village, some people say they were told about a survey for a glass factory, and in yet another, there was apparently talk of a hotel. </p>
<p>Now, in October 2023, the official business and government plans have revealed a much larger development than was suggested in 2004. The “Rempang ecocity” will be an industrial, service, and tourism area, as envisioned in the National Strategic Programme (PSN) of 2023. It is a joint venture between <a href="https://bpbatam.go.id/en/profile/background/">BP Batam</a> (which incorporates the free trade zone and Free Port Management Agency) and PT MEG. <a href="https://futuresoutheastasia.com/rempang-eco-city/">The project aims to attract investment</a> of about 381 trillion Indonesian Rupiah (Rp) by 2080, creating jobs for 30,000 workers. This equates to around US$24.8 billion or £20 billion. </p>
<p>Crucially, there is a major international investor: the <a href="https://www.aljazeera.com/news/2023/9/27/how-a-china-deal-put-the-homes-of-thousands-of-indonesians-at-risk">world’s largest manufacturer of glass and solar panels</a>, China’s <a href="https://www.xinyiglass.com/en/">Xinyi Glass</a>. And the “glass factory” is no ordinary enterprise. It is a mega-investment from Xinyi which has reportedly pledged US$11.6 billion for the factory over several decades. In return, it seems, they have been promised Rempang’s land. </p>
<p>In <a href="https://www.tandfonline.com/doi/abs/10.1080/03066150.2020.1764542">my previous research</a> I called a similar zone of special economic interest in India, “hydra-like”. That’s because these sought after zones change shape, name and purpose according to what’s profitable at a particular point in time. And what’s profitable in Indonesia, and the world today, is the transition to green energy. Therefore, the showpiece of the Rempang ecocity proposal is the mega solar panel manufacturing facility that will probably supply the world with solar panels in the near future.</p>
<p>In the existing vision of the ecocity, there will be <a href="https://futuresoutheastasia.com/rempang-eco-city/">several zones</a> for industries, commercial and residential purposes, tourism, solar farms, and wildlife and nature. Rempang currently sustains farmers, fishers, seaweed processors and exporters, traders and shopkeepers, seafood kelongs, ten primary schools, three junior high schools, a senior school, hospitals, tourist guest houses and more. But it seems there is no place for this community in the futuristic vision of “green” Rempang. </p>
<h2>A project of strategic importance</h2>
<p>The proposed solar panel manufacturing facility, and the Rempang ecocity, may be a portent of a globalised production boom that the government of Indonesia, and its partner countries like China, envision for this region. This economic vision intends to draw on Indonesia’s <a href="https://theconversation.com/jobless-youth-raise-risk-of-indonesias-demographic-bonus-turning-into-disaster-50402">young and cheap labour</a>, its land and natural resources like silica, <a href="https://www.ft.com/content/aae97af3-02ac-4723-a6fd-dbb0e5de55ff">nickel and cobalt</a>, and its willingness for regulatory flexibility. </p>
<p>It is this flexibility that made the government declare the proposed Rempang ecocity as a <a href="https://www.eco-business.com/opinion/why-has-batams-rempang-eco-city-national-project-become-a-controversy/#:%7E:text=Rempang%27s%20Eco%2DCity%20was%20upgraded,US%2425%20billion">Project of National Strategic Importance</a>, allowing it <a href="https://iopscience.iop.org/article/10.1088/1755-1315/886/1/012071/pdf">to bypass social and environmental impact assessments, and acquire land quickly</a>.</p>
<p>The strategic importance of the Rempang project has not been lost on my contacts in Rempang. One of them speculated that the <a href="https://www.nytimes.com/interactive/2023/05/16/headway/indonesia-nusantara-jakarta.html">government’s plans</a> to build a <a href="https://theconversation.com/a-tale-of-two-cities-why-indonesia-is-planning-a-new-capital-on-borneo-and-abandoning-jakarta-podcast-181134#:%7E:text=Indonesia%20plans%20to%20move%20its,island%20of%20Borneo%20called%20Nusantara.">new capital city on Borneo</a> could be a motive for closer relations with China. They wondered whether the money for the new capital Nusantara would come from China, and whether that was why their land in Rempang had been “gifted” to the Chinese.</p>
<p>Another said: “Did they ask us? No. They only value investment. Not people.” Still others draw links with China’s <a href="https://theconversation.com/uk/topics/china-belt-road-initiative-44606">Belt and Road Initiative</a>, which has invested heavily in Indonesian infrastructure.</p>
<p>Not far from Rempang is one such investment: the series of bridges that will connect two of the largest islands in Riau province: the Batam-Bintan bridge project spread over <a href="https://batamterminal.com/7-km-batam-bintan-bridge-project/">7 kilometres</a>. Funded by the China-led <a href="https://www.aiib.org/en/projects/details/2022/special-fund/Indonesia-Support-for-Indonesia-Batam-Bintan-Bridge-Project.html">Asia Infrastructure Investment Bank</a>, the bridge will make it even easier to manufacture on Indonesia’s westernmost islands and carry this produce by road and sea to Singapore and the rest of the world.</p>
<p>The Rempang project may also be part of a looming trade war between China, the US and the EU. In 2022, China manufactured <a href="https://www.npr.org/2023/05/17/1173250926/solar-power-eu-germany-china">three quarters of the world’s solar panels</a> and produced 97% of the silicon wafers that go into them. So far, the bulk of this production has been in Inner Mongolia and Xinjiang, which have a poor human rights record towards minorities like Uyghurs. Concerns around forced labour and Uyghur “re-education” camps, have <a href="https://www.theguardian.com/world/2021/jun/25/us-bans-target-chinese-solar-panel-industry-over-xinjiang-forced-labor-concerns">attracted sanctions from the west</a>.</p>
<p>This has come with protectionist policies towards <a href="https://www.unpri.org/download?ac=17824">emerging solar industries in the EU and America</a>. That is, to encourage national renewables manufacturing and create much needed green jobs, western governments are ready to generously subsidise manufacturers, while heavily taxing imports from competitors like China. <a href="https://www.carbonbrief.org/media-reaction-us-inflation-reduction-act-and-the-global-clean-energy-arms-race/">This international trade tussle</a> begs the question: does mass solar industrial manufacturing in a third country allow China to bypass sanctions and retain its domination of global solar panel manufacturing?</p>
<h2>Sand: a critical resource in the renewables push</h2>
<p>We know that the <a href="https://www.iea.org/topics/critical-minerals">green transition will require critical minerals</a> like cobalt, lithium and nickel to produce electric vehicles, solar cells and wind turbines. Indonesia has some of the world’s <a href="https://www.energymonitor.ai/extractive-industries/the-top-ten-critical-minerals-powerhouses-of-the-energy-transition/?cf-view">largest deposits of nickel and cobalt</a>, making it extremely attractive for countries and companies involved in the renewables push. </p>
<p>Rempang is not known for critical mineral or metal deposits. Yet, apart from its strategic location in the South China Sea, overlooking Singapore, Rempang is sitting on a crucial resource in the renewables transition: sand. Rempang, and its surrounding islands are abundant in silica and quartz sand, which is the <a href="https://interestingengineering.com/innovation/from-sand-to-solar-panels-unveiling-the-journey-of-solar-panel-manufacturing">base material for the manufacture of glass, and solar panels</a>.</p>
<p>Mass mining of sand is considered a <a href="https://www.theguardian.com/cities/2017/feb/27/sand-mining-global-environmental-crisis-never-heard">global environmental crisis that often goes unreported</a>. The world over, a push for infrastructure and urbanisation is founded on massive supplies of cement and concrete, which are made from sand. By 2060, the world is expected to require <a href="https://theweek.com/news/science-health/960931/why-is-the-world-running-out-of-sand#">4.6 billion tonnes of sand</a>. The hunger for solar panels is part of this global sand rush.</p>
<p>Indonesia is at the heart of the sand trade. For years, it has supplied sand to Singapore. Official figures suggest that between 1997-2002 alone, Singapore imported 150 million tonnes of sand from Indonesia. Between 1999-2019, Singapore has shipped in <a href="https://www.straitstimes.com/asia/se-asia/indonesia-scraps-two-decade-ban-on-sea-sand-exports">517 million tonnes of sand </a> from neighbours like Malaysia, Indonesia and Cambodia. </p>
<p>Riau Islands are directly affected, with several islands shrinking significantly in area due to legal and illegal sand export to Singapore. <a href="https://www.asiasentinel.com/p/indonesia-resume-sand-exports-raising-fears">About a quarter of Singapore</a>, including iconic spaces like Marina Bay Sands and the luxury beach and resort area of Sentosa <a href="https://www.channelnewsasia.com/singapore/sentosa-history-50-years-golden-jubilee-2547546">are built on reclaimed land</a> with imported sand. The losers in this process of <a href="https://academic.oup.com/edited-volume/44609/chapter-abstract/393367359?redirectedFrom=fulltext">land-making</a> have been fishworkers, and others dependent on coastal land and waters, including my contacts in the Riau Islands. Fishworkers I have met speak of muddied waters, islands disappearing and drastic reduction in fish and seaweed at the peak of the sand trade.</p>
<p>In 2003, facing irreversible environmental harm, including rising seawater owing to reduced sand and mangrove plant buffers, Indonesia banned the sand trade. Yet, the <a href="https://www.ft.com/content/5359d629-365c-4cd5-94dd-49eb168be1a2">illegal trade in sand went on</a>. In 2023, <a href="https://www.straitstimes.com/asia/se-asia/indonesia-scraps-two-decade-ban-on-sea-sand-exports">sand is back on the government’s agenda</a> as a legally <a href="https://www.greenpeace.org/southeastasia/press/58968/sea-sand-export-returns-after-a-20-year-ban/">tradeable commodity</a>. Rempang is very likely to face the repercussions of renewed sand mining.</p>
<h2>Compensation: a drop in the ocean</h2>
<p>The ecocity and solar panel project are a priority for the government of Indonesia. Ministers have now been deployed to the site to convince locals to support the project, and to hear them out. This includes the investment minister, <a href="https://en.tempo.co/read/1773595/minister-bahlil-visits-rempang-island-to-find-best-solution-without-violence">Bahlil Lahadalia</a>.</p>
<p>At the same time, residents were handed an eviction date of September 28, 2023. Representatives of <a href="https://bpbatam.go.id/en/">BP Batam</a> told them to sign consent forms by mid-September or risk losing the compensation on offer. Finally, villagers were made aware of the terms of compensation: a 45-square metre house, on 500 square metres of land. The house and land is estimated to cost around Rp120 million, or £6,257.</p>
<p>Residents rejected the compensation, with some instead demanding a 70-sq metre house, 1,000sq metres of land, and Rp200 million in cash. As a political commentator indicated <a href="https://kbanews.com/english-edition/land-and-cultural-conflict-in-rempang-balancing-progress-and-heritage/">in the local press</a>, if the government were to meet this higher demand, it would cost them Rp1.04 trillion for compensating all residents. When the proposed investment in the ecocity is Rp381 trillion, what is a compensation amount of a little under 0.3% of the total cost? </p>
<p>While the government is finally in talks with people at Rempang, and as compensation is being discussed, some people have already signed relocation papers. Some say they have been under intense pressure to do so. </p>
<p>This, however, is not the narrative being pushed by BP Batam which is now trying to win a PR war. In its latest press release <a href="https://bpbatam.go.id/en/progres-rempang-eco-city-25-kk-sudah-tempati-hunian-sementara/">it claimed</a> “most residents at some point have voluntarily accepted the shift”. It quoted the head of BP Batam, Muhammad Rudi, as saying, “there is no coercion or intervention,” and that the choice to be relocated was being made “purely from the hearts of the people” who support the ecocity project.</p>
<p>But others are holding out, convinced that “the Melayu cannot be bought”, or moved from their land. The idea that the local Melayu community is not for sale was repeated by many of my contacts. The powerful slogan was also printed on posters that have gone up in Rempang villages in the gathering movement against the glass factory and ecocity.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1703568089239998469"}"></div></p>
<p>Rumours and threats that the resistance at Rempang will lead to the cancellation of the project are beginning to be circulated. These have been <a href="https://inp.polri.go.id/2023/09/20/minister-luhut-confident-in-xinyi-groups-rempang-investment-amid-conflicts/">denied</a> at the highest levels but protests have forced the government to postpone the eviction date, even as they remain determined to start solar panel production at Rempang by <a href="https://www.bloomberg.com/news/articles/2023-09-27/indonesia-to-build-25-billion-project-rocked-by-violent-clashes?leadSource=uverify%20wall">2024</a>. The government has also been compelled to <a href="https://voi.id/en/economy/314059">negotiate with protestors</a> regarding compensation, and has shifted the site of relocation from Galang Island to <a href="https://www.thejakartapost.com/front-row/2023/10/02/visit-to-tanjung-banon-indicates-eco-city-development-is-near.html">Tanjung Banon</a>, a district in the south-eastern corner of Rempang.</p>
<p>There is also talk of a phased relocation and a reduced project area. Some in the government have suggested that shifting within the same island, and fishing just a few kilometres past their old homes, can hardly even be called relocation. But for those who continue to resist the project, their only true home is where they currently live, and where their histories lie. Having had to reckon with relocation, residents are asking fundamental questions like: where will our children study? And, will the solar panel factory displace <a href="https://voi.id/en/news/311679">Melayu ancestral graves</a>?</p>
<p>After fighting alone for their rights for months, the people of Rempang finally have assistance from civil society groups and legal aid organisations. In August 2023, a civil society activist from Jakarta told me “there are too many resource and land conflicts in Indonesia. Something or other is always happening on our 17,500 islands. It is hard to keep up, and be involved in everything”.</p>
<p>But from September, <a href="https://en.tempo.co/read/1775087/civil-coalition-opens-legal-aid-post-in-rempang">prominent civil society groups</a> are assisting the residents of Rempang with a strategy for pushing back. Legal aid has been offered to them relating to their land rights as long-term residents – some of whom trace their connection to Rempang at least to the <a href="https://www.foei.org/rempang-island-indonesia-solidarity/">early 1800s</a>.</p>
<h2>The green transition’s collateral damage?</h2>
<p>My contacts at Rempang had been contemptuous of the suggested shift to Galang Island, and are not impressed by the alternate, smaller site at Tanjung Banon either. One said: “How can you take people from 16 villages, and put them in one small island? There will be conflict over land, and fishing. We are all fishers.” Adding to this incredulity is the idea that the government could even consider moving them to Galang — an island they know as the “Vietnamese refugee island”.</p>
<p>Galang housed boat people from Vietnam, Cambodia, and Laos under the auspices of the <a href="https://refugeecamps.net/GalangCamp.html">UNHCR between 1975-1996</a>. These were refugees in limbo, as they sought clearance of paperwork to emigrate to richer countries like the US and Australia. More recently, Galang housed the area’s main <a href="https://www.thejakartapost.com/indonesia/2022/12/22/galang-island-covid-emergency-hospital-closes.html">COVID emergency hospital</a>. People I am speaking to are understandably furious at being seen as “residue” by their own government – successors to a land that housed refugees and the sick and dying that needed to be isolated from the rest of society.</p>
<p>It is easy to understand the fury of those being left behind, or even trodden on, in the global march for greener energy. These local populations are, sometimes literally, at the coalface of the transition, yet their needs – and sometimes even their human rights – are deemed of little importance. </p>
<p>It is often Chinese investment, which makes the <a href="https://time.com/6313609/indonesia-rempang-eco-city-protests-china/">headlines</a>. But my ongoing research makes it clear that local people as residue is at the heart of this area’s longstanding development model. Indeed, as my <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/dech.12742">writing on the global south</a> more broadly shows, colonial and postcolonial development, and continuing north-south structural inequalities are built on the idea of the residual, racialised, inferior “other”. </p>
<p>The transition to green energy is reinforcing these long-held hierarchies. Events in Rempang are just the tip of the iceberg, as the poorer areas of the south become suppliers in the world’s energy needs.</p>
<p>Batam, and its neighbouring islands in Riau, were first conceptualised as an oil trading and logistics zone by US companies and fossil fuel contractors in the late 1960s. The US had aligned with the military <a href="https://theconversation.com/backgrounder-what-we-know-about-indonesias-1965-anti-communist-purge-66338">General Suharto</a>, against left-leaning nationalist President Sukarno in the fraught Cold War context. With US support, Suharto’s dictatorial New Order ruled Indonesia from 1968-98. </p>
<p>The US was the biggest oil producer in Indonesia at this time, with <a href="https://www.caltex.com/id/en/about-us/who-we-are/our-journey.html">Caltex</a>, a joint venture between Texaco and Chevron, producing <a href="https://oilandgascourses.org/the-amazing-chevron-pacific-indonesia/">a million barrels of oil per day</a> at its peak. Batam, as a regional logistics – and then a manufacturing and services – hub, is a creation of the Suharto-era. It was a major outlet for the crude oil trade from Batam to Singapore, and further afield. It was also an inlet for refined oil, with western oil companies and their enablers in Indonesia hiving off profits at the expense of a decimated environment, and a <a href="https://monthlyreview.org/2022/12/01/mining-capital-and-the-indonesian-state/">dispossessed local population</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-tale-of-two-cities-why-indonesia-is-planning-a-new-capital-on-borneo-and-abandoning-jakarta-podcast-181134">A tale of two cities: why Indonesia is planning a new capital on Borneo – and abandoning Jakarta. Podcast</a>
</strong>
</em>
</p>
<hr>
<p>Meanwhile, people on the small islands around Batam receive between four and six hours of electricity a day from the public utility provider. They experience a sense of déjà vu, as their government starts yet another ambitious project with foreign companies. Once more, their resources are to be ploughed into a money-spinning investment. They will be residue, to be signed off the land. Except this time, in the hotbed of Rempang, they have decided to fight back.</p>
<p>As the world looks to up its green energy consumption, with attendant demands on resources like sand, land and water, we will do well to consider the likely winners and losers in this process. There is a lot of talk on climate and energy justice in international circles right now. The idea of a green energy transition that can be “<a href="https://climatepromise.undp.org/news-and-stories/what-just-transition-and-why-it-important">just</a>” is absent from the volatile spaces of Rempang.</p>
<p>Faced with losing everything they call their own, the people of Rempang are not waiting for justice to be delivered to them. They are fighting for it on the ground. It might be the only way they will be heard, and counted, in the global green energy transition.</p>
<p><em>The Conversation approached the Indonesian government and the Artha Graha group for comments but none were received by time of publication.</em></p>
<hr>
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<img alt="" src="https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=112&fit=crop&dpr=1 600w, https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=112&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=112&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=140&fit=crop&dpr=1 754w, https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=140&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=140&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em>For you: more from our <a href="https://theconversation.com/uk/topics/insights-series-71218?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=InsightsUK">Insights series</a>:</em></p>
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<li><p><em><a href="https://theconversation.com/my-home-city-was-destroyed-by-war-but-i-will-not-lose-hope-how-modern-warfare-turns-neighbourhoods-into-battlefields-211627">‘My home city was destroyed by war but I will not lose hope’ – how modern warfare turns neighbourhoods into battlefields</a></em></p></li>
<li><p><em><a href="https://theconversation.com/beatrix-potters-famous-tales-are-rooted-in-stories-told-by-enslaved-africans-but-she-was-very-quiet-about-their-origins-202274">Beatrix Potter’s famous tales are rooted in stories told by enslaved Africans – but she was very quiet about their origins
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<p>_To hear about new Insights articles, join the hundreds of thousands of people who value The Conversation’s evidence-based news. <a href="https://theconversation.com/uk/newsletters/the-daily-newsletter-2?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=InsightsUK"><strong>Subscribe to our newsletter</strong></a>.</p><img src="https://counter.theconversation.com/content/214755/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nikita Sud receives funding from the Oxford University Press supported John Fell Fund at Oxford University. Grant reference: 0012658.</span></em></p>The international quest for green energy is reliant on ‘sacrificial zones’ in developing countries.Nikita Sud, Professor of the Politics of Development, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2126662023-09-28T12:28:30Z2023-09-28T12:28:30ZSea glass, a treasure formed from trash, is on the decline as single-use plastic takes over<figure><img src="https://images.theconversation.com/files/550352/original/file-20230926-29-z2b42x.png?ixlib=rb-1.1.0&rect=3%2C19%2C2114%2C1390&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Every piece of sea glass has a story − but sea glass could be on the decline. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/handful-of-sea-glass-royalty-free-image/1442716713?phrase=sea+glass&adppopup=true">Olga Pankova/Moment</a></span></figcaption></figure><p>When you stroll along a beach, you may look down and spot colorful bits of worn glass mixed in with the sand. But the little treasures you’ve found actually began as discarded trash. </p>
<p>As an <a href="https://www.uml.edu/sciences/eeas/faculty/weeden-lori.aspx">environmental science professor</a>, I find these gifts from the sea particularly interesting. I have analyzed sand from across the world and added samples, including one of sea glass, into a collection for the environmental, earth and atmospheric sciences at UMass Lowell. The way this trash-turned-treasure washes up on beaches reflects an intersection between human activity and Earth’s natural processes.</p>
<h2>A history of glass</h2>
<p>Prior to the proliferation of single-use plastics starting in the early 1970s, glass was the container of choice. People in <a href="https://www.worldhistory.org/article/592/roman-glass/">ancient Egypt, Greece and Rome</a> used glass for windows, bottles, plates, bowls and more. </p>
<p>In the mid-20th century, people across the United States had milk bottles <a href="https://food52.com/blog/20229-milkmen-history">delivered to their homes</a>, and soda came in <a href="https://www.waybacktimes.com/collecting/short-history-glass-bottles/">glass bottles</a>. After these glass containers served their purpose, users would toss them into a dump. </p>
<p>Before the <a href="https://www.pbs.org/wgbh/americanexperience/features/earth-days-modern-environmental-movement/">environmental movements of the 1960s</a>, trash dumps in the United States were often left open and exposed to rain and wind. As many of <a href="https://www.epa.gov/ocean-dumping/learn-about-ocean-dumping#Before%5D">these trash heaps</a> sat near waterways or coves, runoff would wash the trash – including discarded glass bottles – into the ocean.</p>
<p>On their way to the ocean, glass bottles would run into rocks and other objects, which would break the glass into smaller pieces. When these fractured bits traveled close enough to the coast, high tides and incoming waves would wash them out to sea. </p>
<p><a href="https://doi.org/10.2110/jsr.2010.077">Wave action</a> causes these fragments to slide and roll along the sandy seafloor. It’s this movement that rounds the glass’ sharp edges and gives the once smooth and clear glass its pitted, frosted appearance.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/547052/original/file-20230907-15-tzx3s9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Plastic waste litters sand on a beach, with waves seen in the background." src="https://images.theconversation.com/files/547052/original/file-20230907-15-tzx3s9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/547052/original/file-20230907-15-tzx3s9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=296&fit=crop&dpr=1 600w, https://images.theconversation.com/files/547052/original/file-20230907-15-tzx3s9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=296&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/547052/original/file-20230907-15-tzx3s9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=296&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/547052/original/file-20230907-15-tzx3s9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=372&fit=crop&dpr=1 754w, https://images.theconversation.com/files/547052/original/file-20230907-15-tzx3s9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=372&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/547052/original/file-20230907-15-tzx3s9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=372&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">With the shift to single-use plastic, beaches have more plastic waste and less sea glass.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/home/search?query=plastic%20pollution%20beach&mediaType=photo&st=keyword&vs=true">AP Photo/Julio Cortez</a></span>
</figcaption>
</figure>
<h2>Sand to glass, then back to the sand</h2>
<p>All glass, including sea glass, <a href="https://www.glassallianceeurope.eu/en/what-is-glass">begins as sand</a>, specifically <a href="https://www.sandatlas.org/quartz-sand/">quartz sand</a>. Quartz sand is clear or white – you can see it on many beaches along <a href="https://www.scgov.net/Home/Components/FacilityDirectory/FacilityDirectory/521/4318">Florida’s Gulf Coast</a>. </p>
<p>To make glass from sand, <a href="https://www.ftmmachinery.com/blog/high-purity-quartz-sand-what-is-it-used-for-and-how-to-get-it.html">refiners first purify their quartz sand</a> using both physical and chemical processes to remove all minerals but quartz. They then melt the remaining quartz sand, add a bit of soda ash and limestone to increase the malleability and strength of the glass, and reform it into bottles, bowls, windows and more. </p>
<p>Because quartz is the foundation of all glass, many of <a href="https://geologyscience.com/minerals/quartz/?amp">the mineral’s characteristics</a> are reflected in sea glass. The most obvious is its clarity – quartz is nearly translucent – but also how quartz fractures or breaks. Quartz fractures tend to be a special type of break, called a conchoidal fracture. This type of fracture begins from a single point and breaks outwardly in a semicircular shape, so that the broken surface kind of looks like the inside of a seashell. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/550355/original/file-20230926-26-kdhsgt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A zoomed in look at sand -- several small rocks of varying colors, from yellow to white to gray." src="https://images.theconversation.com/files/550355/original/file-20230926-26-kdhsgt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/550355/original/file-20230926-26-kdhsgt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=370&fit=crop&dpr=1 600w, https://images.theconversation.com/files/550355/original/file-20230926-26-kdhsgt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=370&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/550355/original/file-20230926-26-kdhsgt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=370&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/550355/original/file-20230926-26-kdhsgt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=466&fit=crop&dpr=1 754w, https://images.theconversation.com/files/550355/original/file-20230926-26-kdhsgt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=466&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/550355/original/file-20230926-26-kdhsgt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=466&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The yellowish piece of glass pictured in the center has a conchoidal fracture common for quartz.</span>
<span class="attribution"><span class="source">Lori Weeden</span></span>
</figcaption>
</figure>
<p>Quartz is also <a href="https://geologyscience.com/minerals/quartz/?amp">highly resistant to chemical weathering</a>. Because sea glass is made from quartz, it tends to break down into smaller fragments, but it won’t weather away quickly.</p>
<p>Most sea glass spends <a href="http://www.seaglassjournal.com/articles/pureseaglass/lamotte.htm">at least a few decades</a> on the seafloor getting tossed around and smoothing its sharp edges in the sand. Some pieces of sea glass are estimated to be <a href="http://www.seaglassjournal.com/articles/pureseaglass/lamotte.htm">hundreds of years old</a> – it’s quartz’s hardiness that allows sea glass to persist in the environment for such a long time. </p>
<h2>A global industry</h2>
<p>Selling and trading sea glass is a multimillion-dollar industry in the United States, supported by organizations like the <a href="https://www.westcoastseaglass.com/north-american-sea-glass-association">North American Sea Glass Association</a> and the <a href="https://seaglassassociation.org/">International Sea Glass Association</a>.</p>
<p>Sea glass jewelry and collections populate craft shows all around the country. There are likely very few beach towns in the United States without a local sea glass jeweler selling custom designs. </p>
<p>With the <a href="https://www.reuters.com/business/environment/single-use-plastic-waste-rises-2019-2021-despite-pledges-2023-02-06/">explosion of single-use plastics</a> as an alternative to glass bottles, sea glass may soon become <a href="https://inweh.unu.edu/global-bottled-water-industry-a-review-of-impacts-and-trends/">harder to find</a>, with less glass and more plastic in the supply chain. </p>
<p>As sea glass becomes harder to find, some retailers are creating their own artificial sea glass using rock tumblers and chemicals. The difference between the real and artificial beach glass <a href="https://seaglassassociation.org/genuine-vs-artificial/">is subtle</a> but still recognizable. Artificial sea glass has a uniformly frosted exterior, without the pitting seen in natural sea glass. </p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/549176/original/file-20230919-29-z0z4m0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A close up image of sand, which looks like small rocks, with a green, translucent piece of sea glass" src="https://images.theconversation.com/files/549176/original/file-20230919-29-z0z4m0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/549176/original/file-20230919-29-z0z4m0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1067&fit=crop&dpr=1 600w, https://images.theconversation.com/files/549176/original/file-20230919-29-z0z4m0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1067&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/549176/original/file-20230919-29-z0z4m0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1067&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/549176/original/file-20230919-29-z0z4m0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1340&fit=crop&dpr=1 754w, https://images.theconversation.com/files/549176/original/file-20230919-29-z0z4m0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1340&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/549176/original/file-20230919-29-z0z4m0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1340&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Artificial sea glass doesn’t have the same pitted texture as real sea glass. Pictured here in green is real sea glass, with small, textured marks across its surface.</span>
<span class="attribution"><span class="source">Lori Weeden</span></span>
</figcaption>
</figure>
<p>The public may eventually become less interested in single-use items and <a href="https://www.washingtonpost.com/climate-solutions/2023/06/07/plastic-alternatives-glass-aluminum-paper/">turn back to glass</a>. Unlike plastic, glass can be <a href="https://www.washingtonpost.com/climate-solutions/2023/06/07/plastic-alternatives-glass-aluminum-paper/">recycled multiple times</a> without losing its integrity, and glass doesn’t have the same environmental impact as <a href="https://education.nationalgeographic.org/resource/microplastics/">microplastics</a>. </p>
<p>But because there aren’t many markets for recycled glass and it’s heavy and difficult to transport, it’s not always financially beneficial <a href="https://cen.acs.org/materials/inorganic-chemistry/glass-recycling-US-broken/97/i6">to recycle glass</a>.</p>
<p>However, activists have demanded environmentally friendly alternatives to <a href="https://doi.org/10.1080/08941920.2020.1801922">single-use plastics</a> in recent years. Aluminum bottles and cans are becoming more popular, and glass will remain an alternative to plastic. Unless it’s properly recycled, discarded glass will continue providing sea glass for the next generations to discover.</p><img src="https://counter.theconversation.com/content/212666/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lori Weeden does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Sea glass, while an eye-catching treasure and a multimillion-dollar industry, exists because of decades of improper waste management.Lori Weeden, Teaching Professor of Environmental Earth and Atmospheric Sciences, UMass LowellLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2086772023-07-19T14:09:18Z2023-07-19T14:09:18ZDrawing in the sand at the beach? Our ancestors did the same 140,000 years ago<figure><img src="https://images.theconversation.com/files/537477/original/file-20230714-23-e17pa4.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">This ammoglyph consists of a circular groove, a central depression and two possible knee impressions.</span> <span class="attribution"><span class="source">Charles Helm</span></span></figcaption></figure><p>The urge to draw images in sand, or create sand sculptures, seems to be irresistible, as a walk on many a modern beach or dune surface will show. Sand is a vast canvas – and may have been used as one for far longer than people realise.</p>
<p>When people think of ancient palaeoart, cave paintings (pictographs), rock engravings (petroglyphs), images on trees (dendroglyphs) or arrangements of rocks in patterns (geoglyphs) might come to mind. Until recently it was only possible to speculate that the oldest art might have been in sand. </p>
<p>We are, respectively, a vertebrate ichnologist who studies the fossil tracks and traces of vertebrates, and a physical geographer, interested in the functioning and long-term evolution of coastal landscapes. </p>
<p>We’re part of a team that has spent the past 15 years studying vertebrate tracksites on South Africa’s Cape south coast that date back to the Pleistocene epoch, between 70,000 and 400,000 years ago. During the course of that research we’ve realised that not only could we identify <a href="https://doi.org/10.17159/sajs.2020/8156">hominin</a> and <a href="https://doi.org/10.1016/j.quascirev.2019.07.039">animal tracks</a>; we were able to recognise <a href="http://www.ifrao.com/wp-content/uploads/2021/04/38-1-Helm-et-al.pdf">patterns</a> that we propose our human ancestors made in the sand: in other words, a new form of palaeoart.</p>
<p>The rocks we mostly find them in are known as <a href="https://doi.org/10.1016/S0012-8252(01)00054-X">aeolianites</a>, the cemented versions of ancient dunes that form along the coastline. Such ancient “sand art” had never been described before, so we coined a new term for it: “ammoglyph” (“ammos” being Greek for “sand”). </p>
<p>In <a href="https://doi.org/10.1080/10420940.2023.2204231">a recent article in the journal Ichnos</a> we provided dates for seven hominin ichnosites (a term that includes tracks and other traces) from the Cape south coast. What we interpreted as ammoglyphs were found at four of those sites. The oldest was dated to between 149,000 and 129,000 years ago.</p>
<h2>Method</h2>
<p>A key challenge when studying any palaeo-record – whether trackways, fossils, or other kinds of ancient sediment – is to determine how old the materials are. In the case of the Cape south coast aeolianites, we use a dating method called <a href="https://www.antarcticglaciers.org/glacial-geology/dating-glacial-sediments-2/optically-stimulated-luminescence/">optically stimulated luminescence</a>. </p>
<p>This shows how much time has passed since the grains of sand were last exposed to sunlight, offering an estimate of when the aeolianite sediments were buried as the ancient dune surfaces were forming. Given how the tracks and markings in this study must have been formed – impressions made on wet sand, followed by rapid burial with new blowing sand – it is a good method as we can be reasonably confident that the dating “clock” started at about the same time as the trackways and markings were created.</p>
<p>Of course, we had to be diligent in trying to exclude other causes of the patterns in rock that we encountered, including modern graffiti. We were able to achieve this with greater confidence in some cases than others. Clearly, though, if our ancestors’ tracks could be preserved on these dune and beach surfaces, so could the patterns that they might have made with a stick or a finger. </p>
<h2>Understanding the marks</h2>
<p>Two of the four sites we dated for this paper only contained what we believe to be ammoglyphs – with no associated track evidence of who made them. The other two contained either knee or footprint impressions in association with the ammoglyphs. At one of the latter sites human forefoot impressions were found in association with a number of linear grooves and small round depressions. We were not able to determine whether these represented palaeoart, were some form of “messaging”, or had a utilitarian function such as foraging.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/worlds-oldest-homo-sapiens-footprint-identified-on-south-africas-cape-south-coast-205310">World's oldest _Homo sapiens_ footprint identified on South Africa's Cape south coast</a>
</strong>
</em>
</p>
<hr>
<p>In terms of age, two of the probable ammoglyph sites stand out. The oldest was dated to between 149,000 and 129,000 years ago.</p>
<p>The findings at this site comprised a series of long, perfectly straight grooves in a triangular pattern that included a bisector of one angle. We jokingly referred to the artist as the “Pleistocene Pythagoras”. This rock was found in a very remote, rugged area, and was destined to be destroyed by high tides and storm surges. We were able to <a href="https://theconversation.com/rock-stars-how-a-group-of-scientists-in-south-africa-rescued-a-rare-500kg-chunk-of-human-history-192508">successfully rescue it</a> by helicopter and have it curated and displayed in the Blombos Museum of Archaeology in Still Bay. </p>
<p>The second site was dated to around 136,000 years ago, give or take about 8,000 years. It comprised almost two thirds of a circular groove, a central depression, and two possible knee impressions. The rock surface was broken at the edges of the circle; in all likelihood the original circle was complete. One property of sand that is absent on other potential palaeoart surfaces is the ease with which a large circle can be inscribed on it, for example through using a forked stick. </p>
<p>Our interpretation for the circular ammoglyph is that the central depression represents the spot where one end of a forked stick was anchored by a kneeling human, while the other portion was rotated, yielding a near-perfect circle.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/537478/original/file-20230714-18-ykv5sr.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A man holding a forked stick kneels in the sand on a beach, drawing a circle" src="https://images.theconversation.com/files/537478/original/file-20230714-18-ykv5sr.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/537478/original/file-20230714-18-ykv5sr.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=723&fit=crop&dpr=1 600w, https://images.theconversation.com/files/537478/original/file-20230714-18-ykv5sr.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=723&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/537478/original/file-20230714-18-ykv5sr.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=723&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/537478/original/file-20230714-18-ykv5sr.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=908&fit=crop&dpr=1 754w, https://images.theconversation.com/files/537478/original/file-20230714-18-ykv5sr.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=908&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/537478/original/file-20230714-18-ykv5sr.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=908&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Author Charles Helm demonstrates how one of the ammoglyphs was probably made.</span>
<span class="attribution"><span class="source">Linda Helm</span></span>
</figcaption>
</figure>
<p>As anyone who has tried knows, it’s incredibly hard to draw a perfect circle without a compass. We do not yet know how the perfectly straight lines were inscribed; we speculate that perhaps straight reeds were placed in the sand, but there is no way to know for sure.</p>
<p>We also noted similarities between the shapes of some of the purported ammoglyphs and the shapes of ancient geometric engravings made in caves on this coastline, such as <a href="https://theconversation.com/south-africas-blombos-cave-is-home-to-the-earliest-drawing-by-a-human-103017">Blombos Cave</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/south-africas-blombos-cave-is-home-to-the-earliest-drawing-by-a-human-103017">South Africa's Blombos cave is home to the earliest drawing by a human</a>
</strong>
</em>
</p>
<hr>
<h2>An ancient impulse</h2>
<p>Thanks to the dates obtained through our published study, we can conclude that when we encourage our kids and grandkids to play in the sand, and they draw patterns and make sandcastles, they are indulging in a profoundly atavistic activity that extends far into antiquity, as far as at least around 140,000 years. </p>
<p>The creation of art is one of the characteristics that helps to make us human. Knowing that our ancestors so long ago did the same as we do today perhaps helps to add to that sense of “humanness”.</p><img src="https://counter.theconversation.com/content/208677/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Ammoglyphs – ancient ‘sand art’ – are a relatively new find.Charles Helm, Research Associate, African Centre for Coastal Palaeoscience, Nelson Mandela UniversityAndrew Carr, Senior Lecturer, University of LeicesterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1952092022-12-29T20:56:52Z2022-12-29T20:56:52ZHow to get the most out of sand play: 4 tips from a sculptor<figure><img src="https://images.theconversation.com/files/500325/original/file-20221212-93936-zix3b9.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5168%2C3448&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Zhou Yeming/Pexels</span></span></figcaption></figure><p>One of the things kids love most about the beach is the chance to play with sand. Sand is an excellent material to play with. It is <a href="https://journals.sagepub.com/doi/abs/10.23965/AJEC.43.1.04">versatile, widely available</a>, open-ended and cheap.</p>
<p>Not only is it <a href="https://www.tandfonline.com/doi/abs/10.1080/14729679.2015.1122538">nature-based</a>, but it involves manipulation, exploration, and construction with materials to create imaginary worlds.</p>
<p>On top of being endlessly fun, <a href="https://eric.ed.gov/?id=EJ1070242">research also shows</a> clear associations between sand play and children’s physical, cognitive and social–emotional development. This <a href="https://www.communityplaythings.com/resources/articles/2014/Exploring-Sand-Play">includes</a> fine motor and gross motor skills, measurement, cooperative building, sharing and pretending.</p>
<p>Sand is also used in <a href="https://www.sciencedirect.com/science/article/abs/pii/S019745561730254X?via%3Dihub">psychotherapy methods</a> for children. In sand play therapy, children are given a sand pit and helped to communicate their thoughts, experiences and emotions using sand, water, miniature figurines and their hands.</p>
<p>As a nonverbal approach, this therapy is especially effective when working with children experiencing trauma, distress and disabilities.</p>
<p>Here are four tips to make the most of it over summer for you and your kids.</p>
<h2>1. Don’t overthink it</h2>
<figure class="align-left ">
<img alt="A young bots plays with a takeaway cup, making moulds on the beach." src="https://images.theconversation.com/files/500222/original/file-20221211-90420-qh64s7.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/500222/original/file-20221211-90420-qh64s7.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/500222/original/file-20221211-90420-qh64s7.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/500222/original/file-20221211-90420-qh64s7.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/500222/original/file-20221211-90420-qh64s7.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/500222/original/file-20221211-90420-qh64s7.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/500222/original/file-20221211-90420-qh64s7.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">When Dr Sanné Mestrom and her son play with sand, an old coffee cup becomes a handy mould.</span>
<span class="attribution"><span class="source">Sanné Mestrom.</span></span>
</figcaption>
</figure>
<p>While my five-year-old son and I live in the Blue Mountains, we regularly jump on the train to Bronte or Bondi Beach. Once there, I’ll grab a coffee, and we hit the sand. All we will have with us are our togs, a small chamois each and a sarong, which doubles as a beach towel. </p>
<p>For us, it’s important not to be burdened with too much stuff. The beach already has everything we need: sand, water, shells, sticks, rocks, pebbles and other random discarded and found objects. </p>
<p>The coffee cup quickly becomes a small mould for sculpting and doubles as a vessel for carrying sea water. While you can certainly buy great sand accessories (sophisticated brick and castle moulds, for example), these actually limit the potential of open-ended <a href="https://eric.ed.gov/?id=EJ1069007">free-play</a>.</p>
<h2>2. Start with simple ideas</h2>
<p>When you’re given free reign to create whatever you like, the limitless options can be overwhelming. Where do you begin? Let’s start with the simplest things:</p>
<p><strong>Sculpting</strong> </p>
<p>When it’s dry, sand can be mounded, poured, and measured. When it’s wet, the sand can be moulded, shaped, and carved. Repurpose your cup or use recycled plastic containers as sand scoops to form various upturned sculptural shapes. You can of course create a stacked castle with these, or an elaborate, ever-expanding <a href="https://unpluggedfamilytime.com/outdoor-activities-for-kids/mandala-for-kids/">sand mandala</a>. This is an abstract circular pattern of intricate designs that is ultimately washed away. </p>
<p><strong>Structure</strong></p>
<p>Experiment with scientific principles relating to gravity and force to problem solve your sculptures. For example, try reinforcing your sand tunnels with sticks and driftwood to give them structural integrity. The last time we were built tunnels at the beach, we emulated the layers of a large construction bridge we’d seen just days before. It was a great way to take something we’d seen in the built world, and apply it directly to our own sculptures. </p>
<p><strong>Pattern</strong></p>
<p>Walk to the end of the bay and collect as many interesting objects as you can find. This could be an array of dried and contorted seaweed, stripey pebbles, translucent sandblasted glass, bottle tops and textured and colourful seashells. The more the better. Try to find patterns in texture, scale, colour and form and use these to extend your sculpture project.</p>
<figure class="align-center ">
<img alt="A young child makes a mandala in the sand with feathers." src="https://images.theconversation.com/files/500330/original/file-20221212-94530-i0rnah.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/500330/original/file-20221212-94530-i0rnah.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/500330/original/file-20221212-94530-i0rnah.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/500330/original/file-20221212-94530-i0rnah.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/500330/original/file-20221212-94530-i0rnah.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/500330/original/file-20221212-94530-i0rnah.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/500330/original/file-20221212-94530-i0rnah.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Collect feathers, pebbles and shells and make a sand mandala.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>3. Try and find the flow state</h2>
<p>As a lecturer in sculpture, I apply the same principles to my art students as I do to my young son: make sure give yourself plenty of open-ended, unstructured time. Sand play is first and foremost a creative pursuit, and as with any creative pursuit, you need to allow for as much time as possible to enter the “<a href="https://link.springer.com/article/10.3758/s13423-018-1517-7">flow state</a>”.</p>
<p>This happens when we become so deeply focused on a task and pursue it so effortlessly that all else disappears, including the passage of time, worry of failure, self-reflection, self-critique, or sense of authorship.</p>
<h2>4. Use the beach as a conversation starter</h2>
<p>The beach is not just about the waves, the sand and ice-creams. It can provoke ideas and conversations, big and small. For example: </p>
<ul>
<li><p>think about how far your shells and glass might have travelled to find their way to your feet. I recall collecting an ancient coconut fossil on a beach in northern New Zealand as a child. It was a small, shrunken black nugget – the size of a strawberry. I found the idea of this transformation mind-blowing and still have the little treasure with me to this day</p></li>
<li><p>collect rubbish at the beach and talk about <a href="https://www.natgeokids.com/au/kids-club/cool-kids/general-kids-club/plastic-pollution/">single-use plastic</a> – how far plastic pollution can travel and how dangerous it is for ocean life</p></li>
<li><p>and my favourite: use your time at the beach to chat about the phenomena that give shape to our everyday lives, such as the <a href="https://theconversation.com/curious-kids-how-does-the-moon-being-so-far-away-affect-the-tides-on-earth-105371">interconnection of ocean tides</a>, the moon and gravity, how <a href="https://www.abc.net.au/kidslisten/programs/imagine-this/why-are-there-waves/11093006">waves travel</a> across the globe, and how the <a href="https://stemplayeveryday.com/sundials/">sun maps</a> the movement of time.</p></li>
</ul>
<p>In this way, sand play is not just for children, it enriches us all. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/this-new-risky-playground-is-a-work-of-art-and-a-place-for-kids-to-escape-their-mollycoddling-parents-193218">This new ‘risky' playground is a work of art – and a place for kids to escape their mollycoddling parents</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/195209/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sanné Mestrom receives funding from the Australian Research Council</span></em></p>Sand is an excellent material to play with. It is versatile, widely available, open-ended and cheap. And you don’t need a fancy plastic mould to make something special.Sanné Mestrom, Senior Lecturer, DECRA Fellow, Sydney College of the Arts, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1920142022-11-14T19:00:33Z2022-11-14T19:00:33ZAt least 700,000 years ago, the world’s largest sand island emerged as the barrier that helped the Great Barrier Reef form<figure><img src="https://images.theconversation.com/files/494994/original/file-20221114-15-f7r4qi.jpg?ixlib=rb-1.1.0&rect=1279%2C0%2C4749%2C3215&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Scientists had always been puzzled why the Great Barrier Reef formed long after Australia had conditions suitable for reef growth. It turns out the answer might be K'gari (Fraser Island). </p>
<p>K’gari, the world’s largest sand island and a <a href="https://whc.unesco.org/en/list/630/">UNESCO World Heritage Area</a>, juts out from the Australian coastline where the continent extends furthest east. It lies at the northern end of one of the world’s largest and longest <a href="https://www.internetgeography.net/topics/what-is-longshore-drift/">longshore drift</a> systems. If not for the presence of K’gari, the sand carried by this system would continue to migrate northward directly into the area of the Great Barrier Reef, which starts a little north of the island.</p>
<p>The volumes of sand carried along the coast are immense. It is estimated <a href="https://www.abc.net.au/news/2020-06-13/weather-longshore-drift-queensland-nsw-beaches/12347828">500,000 cubic metres of sand</a> moves north past each metre of shoreline every year. </p>
<p>K’gari plays a key role in delivering this sand to the deep ocean. Sand moving along its eastern beaches is directed across the continental shelf and into the deep immediately north of the island. The dominant south-easterly trades would drive sand all the way into the full tropics if K’gari did not direct it off the shelf.</p>
<p><a href="https://www.nature.com/articles/s41561-022-01062-6">Our research</a>, published today, has established the age of K'gari as being older than the Greater Barrier Reef. This suggests the reef became established only after the island protected it from the northward drift of sand.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/437049/original/file-20211212-170692-b3s288.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/437049/original/file-20211212-170692-b3s288.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/437049/original/file-20211212-170692-b3s288.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=672&fit=crop&dpr=1 600w, https://images.theconversation.com/files/437049/original/file-20211212-170692-b3s288.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=672&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/437049/original/file-20211212-170692-b3s288.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=672&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/437049/original/file-20211212-170692-b3s288.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=844&fit=crop&dpr=1 754w, https://images.theconversation.com/files/437049/original/file-20211212-170692-b3s288.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=844&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/437049/original/file-20211212-170692-b3s288.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=844&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The northernmost point of K’gari, Sandy Point, marks where the sand heads deeper underwater, moving along the continental shelf before dropping off the edge.</span>
<span class="attribution"><span class="source">Data: Geoscience Australia Landsat 5 and 8 Geomedian. Compilation: Will Farebrother, from Conversation article by Hanna Power</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/from-enormous-tides-to-millions-of-shells-here-are-6-unique-beaches-for-your-summer-road-trip-169164">From enormous tides to millions of shells, here are 6 unique beaches for your summer road trip</a>
</strong>
</em>
</p>
<hr>
<h2>Why does the reef depend on the island?</h2>
<p>The southern limit of the Great Barrier Reef is not a result of the climate being too cool further south. Corals can and do grow many hundreds of kilometres further south in places like Moreton Bay (Brisbane) and Lord Howe Island. </p>
<p>The main limiting factor for the southern extent of the reef is the drowning of corals by the rivers of sand going north. The corals in places like Moreton Bay occur where they have a hard substrate to grow on and are sheltered from sediment inundation. </p>
<p>The sand comes from sediment delivered to the Tasman Sea via the Hawkesbury and Hunter rivers in mid-New South Wales. Prevailing south-easterly breezes and their associated coastal wave systems sweep these sediments north for more than 1,000 kilometres. </p>
<p>The geological setting of eastern Australia is rather stable, so this longshore drift system should have been in operation for many millions of years. The Great Barrier Reef corals could not have survived without some protection from this northward flow of sand.</p>
<p>The <a href="https://onlinelibrary.wiley.com/doi/10.1002/esp.5387">techniques</a> we used to establish the age of the coastal dune fields of K’gari and the adjacent Cooloola Sand Mass on the mainland south of K’gari show the first coastal dunes date to about 1 million years ago. The modern dune fields were established by 700,000-800,000 years ago. Prior to 1 million years and definitely prior to 700,000-800,000 years ago, sand would have drifted north into the region of the modern barrier reef. </p>
<figure class="align-center ">
<img alt="Looking out to sea from a coastal dune" src="https://images.theconversation.com/files/494996/original/file-20221114-20-ks48az.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/494996/original/file-20221114-20-ks48az.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/494996/original/file-20221114-20-ks48az.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/494996/original/file-20221114-20-ks48az.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/494996/original/file-20221114-20-ks48az.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/494996/original/file-20221114-20-ks48az.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/494996/original/file-20221114-20-ks48az.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Dating of the Cooloola dune fields on the mainland shows the oldest dunes are about 1 million years old.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/celebrating-kgari-why-the-renaming-of-fraser-island-is-about-so-much-more-than-a-name-168378">Celebrating K’gari: why the renaming of Fraser Island is about so much more than a name</a>
</strong>
</em>
</p>
<hr>
<h2>Why did K'gari form at that time?</h2>
<p>This timing coincides with a major geo-astronomical event, the <a href="https://en.wikipedia.org/wiki/Mid-Pleistocene_Transition">Mid-Pleistocene Transition</a>. At this time Earth’s glacial cycles changed from a period of about 40,000 years to about 100,000 years. This change had a major impact on global sea levels because the longer cycles supported the growth of larger ice caps during cold periods. </p>
<p>Prior to this transition, global sea levels went up and down about 70 metres between warm (interglacial) and cold (glacial) periods. Afterwards, the range increased to 120-130m.</p>
<p>Under a longshore drift system some sediment “leaks” out into deeper water where currents and waves are not strong enough to move it. A drop of 70m would still leave the South-East Queensland coastline on the continental shelf. So, before the Mid-Pleistocene Transition, sand moving north would be gradually stored on the outer parts of the continental shelf, potentially accumulating over millions of years. </p>
<p>Once the first 100,000-year cycle occurred, sea levels would have dropped to the outer edge of the continental shelf. During the start of the next warm period, rising sea levels would erode the accumulated sands and transport it shoreward. This would drive a major period of dune building along the coast. </p>
<p>This was a major event because sediment accumulated over millions of years was added back into the sedimentary system. The very different dune types associated with plentiful sand are recorded in the oldest parts of the cliff sections at Cooloola and K’gari. </p>
<p>Again, remnants of dunes formed when sea levels were low are preserved directly off this coastline. We have shown a major pulse of sand was released into the dune systems formed during the earliest high sea-level periods of the 100,000-year climate cycles.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/climate-explained-humans-have-dealt-with-plenty-of-climate-variability-145043">Climate explained: humans have dealt with plenty of climate variability</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/494999/original/file-20221114-42960-xt8y6i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/494999/original/file-20221114-42960-xt8y6i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/494999/original/file-20221114-42960-xt8y6i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/494999/original/file-20221114-42960-xt8y6i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/494999/original/file-20221114-42960-xt8y6i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/494999/original/file-20221114-42960-xt8y6i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/494999/original/file-20221114-42960-xt8y6i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The extraordinary beauty and diversity of the Great Barrier Reef would not exist without protection from the rivers of sand flowing north along the coast.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>How does that line up with the age of the reef?</h2>
<p>K’gari was constructed in its “modern” form between about 1 million and 700,000 years ago. Once it was in place, any further sand driven up the coast during interglacial high sea levels was lost to deep water off the north of K’gari.</p>
<p>The last piece of the puzzle is the age of the Great Barrier Reef. For a heavily investigated natural wonder, this is remarkably poorly defined, but the oldest evidence dates the reef to <a href="https://doc.rero.ch/record/9147/files/spezzaferri_isc.pdf">about 650,000 years ago</a>. </p>
<p>In short, coral reef development appears to not have started until sediment drift from the south was blocked off. In this way the whole of the east coast of Australia is linked together as a single story and K’gari has played a key role in the formation and protection of the Great Barrier Reef.</p><img src="https://counter.theconversation.com/content/192014/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>James Shulmeister received funding for this work from the Australian Research Council. James Shulmeister has been funded from the Marsden Fund (NZ), he has also participated in US NSF and Chinese NSF grants as well as received grants from other sources.</span></em></p><p class="fine-print"><em><span>Daniel Ellerton completed his PhD which was funded by the Australian Research Council.</span></em></p>Establishing the age of K'gari (Fraser Island) confirms it emerged before the reef, despite the climate being suitable for coral growth long before then.James Shulmeister, Adjunct Professor, University of Queensland, and Professor and Head of School of Earth and Environment, University of CanterburyDaniel Ellerton, Postdoctoral Researcher, Department of Geological Sciences, Stockholm UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1925012022-10-23T19:02:27Z2022-10-23T19:02:27ZA green trifecta: how a concrete alternative can cut emissions, resource use and waste<figure><img src="https://images.theconversation.com/files/490751/original/file-20221019-25-1i2n1g.jpg?ixlib=rb-1.1.0&rect=0%2C4%2C2749%2C1823&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Building materials and construction generate <a href="https://architecture2030.org/why-the-building-sector/">about 20%</a> of <a href="https://www.ipcc.ch/report/ar6/wg3/downloads/report/IPCC_AR6_WGIII_SPM.pdf">global greenhouse gas emissions</a>. Much of these emissions are due to the environmentally unfriendly process of producing ordinary <a href="https://www.britannica.com/technology/portland-cement">Portland cement</a>, which is widely used in construction materials such as concrete and mortar. </p>
<p>Portland cement production generates about 2.6 billion tonnes of carbon dioxide (CO₂) a year – <a href="https://phys.org/news/2022-06-cement-carbon-dioxide-emissions-quietly.html">more than 7%</a> of annual global emissions. Cement emissions have <a href="https://phys.org/news/2022-06-cement-carbon-dioxide-emissions-quietly.html">doubled in the past 20 years</a>. And over the next 40 years, construction is expected to <a href="https://www.worldgbc.org/sites/default/files/UNEP%20188_GABC_en%20%28web%29.pdf">double the building floor area</a> worldwide.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/buildings-produce-25-of-australias-emissions-what-will-it-take-to-make-them-green-and-wholl-pay-105652">Buildings produce 25% of Australia's emissions. What will it take to make them 'green' – and who'll pay?</a>
</strong>
</em>
</p>
<hr>
<p>Every tonne of cement produced also uses about <a href="https://www.buildinggreen.com/feature/reducing-environmental-impacts-cement-and-concrete">1.6 tonnes of raw materials</a>, including fuels and other resources. Concrete production also uses large amounts of aggregate such as sand and gravel. This requires energy-intensive
quarrying operations that <a href="https://www.conserve-energy-future.com/causes-effects-solutions-depletion-natural-resources.php">deplete non-renewable natural resources</a> – the world is <a href="https://www.bbc.com/future/article/20191108-why-the-world-is-running-out-of-sand">running out of building sand</a>.</p>
<p>The problems of emissions and resource depletion mean suitable substitutes for Portland cement and natural aggregate are required. <a href="https://www.sciencedirect.com/science/article/abs/pii/S0950061822026988">Our research</a> shows it is possible to develop more sustainable construction materials, reinforced using natural fibres. Industrial byproducts and waste materials can be used to replace cement binder and aggregate, reducing emissions, resource depletion and waste. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1582548565414793216"}"></div></p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/green-cement-a-step-closer-to-being-a-game-changer-for-construction-emissions-126033">Green cement a step closer to being a game-changer for construction emissions</a>
</strong>
</em>
</p>
<hr>
<h2>Recycling cuts waste</h2>
<p>Recycling waste materials in construction can help reduce the environmental impacts of concrete and mortar production and the disposal of waste materials in landfills. </p>
<p>These materials include industrial byproducts (fly ash and blast furnace slag), waste glass and lead slag. Fly ash comes from coal-fired power stations. Blast furnace slag is a byproduct of iron and steel production. </p>
<p>A new type of eco-friendly material, <a href="https://www.geopolymer.org/science/introduction/">geopolymer</a>, has received significant attention as a replacement for conventional concrete. A geopolymer is a hard and durable human-made substance. Geopolymer production produces up to <a href="https://www.geopolymertech.com/green-concrete/sustainability/">90% less CO₂ emissions</a> than conventional concrete. </p>
<p>The properties of waste glass and lead slag make them suitable for use in making geopolymer. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/australia-needs-construction-waste-recycling-plants-but-locals-first-need-to-be-won-over-161888">Australia needs construction waste recycling plants — but locals first need to be won over</a>
</strong>
</em>
</p>
<hr>
<h2>Natural fibre reinforcement is sustainable</h2>
<p>Steel or other synthetic fibres have been widely used as reinforcement material to improve the mechanical properties of geopolymer. However, steel fibres are expensive and corrode in harsh environments. </p>
<p>The synthetic alternative, mineral fibres, such as polyvinyl alcohol and polypropylene, are produced using antioxidants and amines. This process makes these fibres a non-eco-friendly material. </p>
<p>Natural fibres obtained from plants are a viable alternative to non-renewable, corrosive and expensive synthetic fibres. Natural fibres are renewable, eco-friendly, non-corrosive, cheap and abundant. These properties make natural fibres a sustainable material. </p>
<h2>What did the study find?</h2>
<p>Any substitutes for the concrete and mortar used today should at least match their engineering properties, such as strength and durability. <a href="https://www.sciencedirect.com/science/article/abs/pii/S0950061822026988">Our study</a> evaluated the production and performance of geopolymers made with waste glass and lead slag instead of natural sand. We used a combination of fly ash and granulated blast furnace slag as binders instead of Portland cement. </p>
<p>These geopolymers were reinforced with different types of natural fibres such as <a href="https://ecoworldonline.com/coir-the-natural-fiber-from-coconut-husk/">coir</a>, <a href="https://ecoworldonline.com/what-material-is-ramie/">ramie</a>, <a href="https://edition.cnn.com/2015/11/10/africa/sisal-tanzania/index.html">sisal</a>, <a href="https://cfda.com/resources/materials/detail/hemp">hemp</a>, <a href="https://www.recycledmats.com.au/what-is-jute">jute</a> and <a href="https://ecoworldonline.com/why-choose-bamboo-fiber-products/">bamboo</a> fibres.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/490745/original/file-20221019-14-kb1yzm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/490745/original/file-20221019-14-kb1yzm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/490745/original/file-20221019-14-kb1yzm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/490745/original/file-20221019-14-kb1yzm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/490745/original/file-20221019-14-kb1yzm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/490745/original/file-20221019-14-kb1yzm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1006&fit=crop&dpr=1 754w, https://images.theconversation.com/files/490745/original/file-20221019-14-kb1yzm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1006&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/490745/original/file-20221019-14-kb1yzm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1006&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Compression load testing of a geopolymer concrete cylinder.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Our experimental results showed geopolymers containing waste glass sand have higher strength and absorb less water than those containing lead slag and natural sand. Water absorption reduces the durability of concrete. </p>
<p>Geopolymers prepared with lead slag show a lower drying shrinkage than geopolymers made with waste glass sand and lead slag. Drying shrinkage also reduces durability, as it leads to cracks in the concrete before it bears any kind of load.</p>
<p>We found that geopolymers with 1% ramie, hemp and bamboo fibre have greater compressive and tensile strengths than unreinforced geopolymers. This means the reinforced geopolymer resists breaking when squeezed (under compression loading) and when pulled apart (under tension loading). The higher strength of natural fibre-reinforced mixes is because of the bridging effect of the fibres inside the geopolymer. </p>
<p>Our study also shows that ramie, hemp and bamboo fibre-reinforced geopolymers shrink less than unreinforced geopolymers. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/490761/original/file-20221020-20-t00rq0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/490761/original/file-20221020-20-t00rq0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/490761/original/file-20221020-20-t00rq0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=451&fit=crop&dpr=1 600w, https://images.theconversation.com/files/490761/original/file-20221020-20-t00rq0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=451&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/490761/original/file-20221020-20-t00rq0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=451&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/490761/original/file-20221020-20-t00rq0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/490761/original/file-20221020-20-t00rq0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/490761/original/file-20221020-20-t00rq0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The results of tension loading tests on different geopolymer samples.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/greening-the-concrete-jungle-how-to-make-environmentally-friendly-cement-82686">Greening the concrete jungle: how to make environmentally friendly cement</a>
</strong>
</em>
</p>
<hr>
<h2>What next?</h2>
<p>The next steps in this research would include study of:</p>
<ul>
<li><p>the use of recycled aggregates obtained from <a href="https://theconversation.com/australia-needs-construction-waste-recycling-plants-but-locals-first-need-to-be-won-over-161888">construction and demolition waste</a>, which has grown to <a href="https://www.dcceew.gov.au/sites/default/files/env/pages/5a160ae2-d3a9-480e-9344-4eac42ef9001/files/nwr2020-factsheet.pdf">27 million tonnes a year</a> in Australia – <a href="https://www.dcceew.gov.au/sites/default/files/env/pages/5a160ae2-d3a9-480e-9344-4eac42ef9001/files/national-waste-report-2020.pdf">44% of all waste</a></p></li>
<li><p>treating the natural fibres to modify their properties before using in the geopolymer</p></li>
<li><p>the possibility of using the developed geopolymer in 3D printing for automated construction. </p></li>
</ul>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/future-cities-could-be-3d-printed-using-concrete-made-with-recycled-glass-175598">Future cities could be 3D printed – using concrete made with recycled glass</a>
</strong>
</em>
</p>
<hr>
<p>Developing sustainable concrete will provide us with a next-generation construction material that greatly improves the sector’s resource efficiency while reducing its emissions and other environmental impacts.</p><img src="https://counter.theconversation.com/content/192501/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Aliakbar Gholampour does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The energy-intensive process of producing cement and concrete contributes significantly to global warming while depleting resources. Much more sustainable alternatives are being developed.Aliakbar Gholampour, Senior Lecturer in Civil and Structural Engineering, Flinders UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1882082022-08-19T12:41:18Z2022-08-19T12:41:18ZSandcastle engineering – a geotechnical engineer explains how water, air and sand create solid structures<figure><img src="https://images.theconversation.com/files/479726/original/file-20220817-11-akqy8d.jpg?ixlib=rb-1.1.0&rect=4%2C16%2C2685%2C1923&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">There's a lot of science behind the natural forces that let this guy work his magic at the beach.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/vpickering/3780119874/">Victoria Pickering/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>If you want to understand why some sandcastles are tall and have intricate structures while others are nearly shapeless lumps of sand, it helps to have a background in geotechnical engineering.</p>
<p>As a <a href="https://scholar.google.com/citations?hl=en&user=UXVFmqIAAAAJ&view_op=list_works&sortby=pubdate">geotechnical engineering educator</a> myself, I use sandcastles in the classroom to explain how interactions of soil, water and air make it possible to <a href="https://dx.doi.org/10.14288/1.0374933">rebuild landscapes after mining</a> metals critical to the energy transition.</p>
<p>Building a sandcastle comes down to the right mix of those three ingredients. Sand provides the structure, but it’s water between the sand grains that provides the force – in this case, suction – that holds the sand together. And without the right amount of air the water would just push the sand grains apart.</p>
<h2>Not just any sand</h2>
<p>Sand grains, according to the standards body ASTM International’s <a href="https://doi.org/10.1520/D2487-17">Unified Soil Classification System</a>, are soil particles having a diameter of 0.003 inches (0.075 mm) to 0.187 inches (4.75 mm). Sands, by definition, have at least half their particles in that range. Silt or clay is soil with particles smaller than sand size. And soil with particles larger than sand size is gravel.</p>
<p>The size of particles, or grains, also determines the way sand looks and feels. The smallest sand grains have a texture almost like powdered sugar. The largest grains are more like the size of small dry lentils.</p>
<p>Most sand will work for building a sandcastle, but the best sand has two characteristics: grains of sand in several different sizes and grains with angular or rough edges. Variation in grain size allows smaller sand grains to fill the pockets, or pores, between the larger sand grains. The result is increased sand strength.</p>
<p>Sand grains that are more angular, with sharp corners on them, lock together better, making the sandcastle stronger. It’s the same reason a pile of angular wooden blocks will stay in a pile, but a pile of marbles will go everywhere.</p>
<p>This is also why, surprisingly, the best sand for sandcastles is not typically found on an island or a coastal beach. More angular grains of sand are usually found closer to mountains, their geologic source. These sand grains have not yet had their edges rounded off by wind and water. Professional sandcastle builders will go so far as to <a href="https://physicsworld.com/a/top-tips-for-super-sandcastles-explore-the-weird-world-of-sand/">import river sand for their creations</a>.</p>
<p>Finally, the closer together the sand grains are, the stronger the sand will be. Pressing wet sand together tightly, by compaction or tamping, squeezes sand grains together, decreasing the size of pores and increasing the effect water can have. Compaction also increases grain interlocking and, consequently, sand strength. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/477696/original/file-20220804-15-ea3gvh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="On a sandy beach, with a plastic green bucket and yellow shovel in the foreground, a blue sky and bluer water in the background, a colorfully swimsuited girl stands with one hand on her hip and the other on a sand castle as tall as she is." src="https://images.theconversation.com/files/477696/original/file-20220804-15-ea3gvh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/477696/original/file-20220804-15-ea3gvh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/477696/original/file-20220804-15-ea3gvh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/477696/original/file-20220804-15-ea3gvh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/477696/original/file-20220804-15-ea3gvh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/477696/original/file-20220804-15-ea3gvh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/477696/original/file-20220804-15-ea3gvh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Building a sandcastle calls for finding the right mix of air, water and sand.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/kids-beach-royalty-free-image/91886579">Tony Garcia/Stone via Getty Images</a></span>
</figcaption>
</figure>
<h2>Water is key</h2>
<p>Without water, sand just forms a pile. Too much water and sand flows like liquid. But between dry sand and saturated sand lies a <a href="https://doi.org/10.1038/nmat2117">wide range of moisture levels</a> that enable sandcastle construction.</p>
<p>Water is cohesive, meaning that water likes to stick to water. But water also sticks to or climbs up certain surfaces. Look at a half-full glass of water and you will see the water going up the insides of the glass a little. Gravity still holds the water in the glass, but the water is trying to climb up and wet the surface. This tiny power struggle is what makes sandcastles possible.</p>
<p>Right where the air and water meet, there’s surface tension. The air-water interface pulls downward, trying to hold the water together against the competing forces of surface wetting, cohesion and gravity. Surface tension pulls the water together like the taut skin of a balloon. And surface tension also pulls sand grains together.</p>
<p>If the glass were much skinnier, like a straw, the water would rise higher and have more surface tension. The narrower the straw, the higher the water would rise. This phenomenon is called <a href="https://www.britannica.com/science/capillarity">capillarity</a>.</p>
<p>Water behaves the same way in wet sand. The pores, or spaces, between the sand grains are like a bunch of very tiny straws. Water forms tiny bridges between the grains. The water in these bridges is under tension, pulling the grains together by a force we geotechnical engineers call <a href="https://doi.org/10.1061/(ASCE)1090-0241(2006)132:2(131)">suction stress</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/479731/original/file-20220817-9126-myzq1x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Greco-Roman style sand sculpture of three bearded men wearing robes" src="https://images.theconversation.com/files/479731/original/file-20220817-9126-myzq1x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/479731/original/file-20220817-9126-myzq1x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/479731/original/file-20220817-9126-myzq1x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/479731/original/file-20220817-9126-myzq1x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/479731/original/file-20220817-9126-myzq1x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/479731/original/file-20220817-9126-myzq1x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/479731/original/file-20220817-9126-myzq1x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Did you know that suction is one of the forces holding this sand sculpture together?</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/azuaje/13829838454/">El Coleccionista de Instantes Fotografía & Video/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Just enough water</h2>
<p>The quantity of water in the sand controls the <a href="https://doi.org/10.1061/(ASCE)EM.1943-7889.0000054">size and strength of the water bridges</a>. Too little water equals little bridges between the sand grains. More water, and the size and number of bridges grows, increasing the suction holding the sand grains together. The result is perfect sandcastle sand.</p>
<p>Too much water, though, and the suction is too weak to hold the sand together. </p>
<p>A general rule of thumb for building great sandcastles is <a href="https://doi.org/10.1038/nphys106">one part water for every eight parts dry sand</a>. Under ideal conditions in a laboratory, though, with dense sand and zero evaporation, one part water for every <a href="https://doi.org/10.1038/srep00549">one hundred parts dry sand</a> can produce wonders. At a beach, sand with the right moisture level is near the high tide line when the tide is low.</p>
<p>Incidentally, salt from seawater can also be a boon for sandcastle stability. Capillary forces hold sand grains together initially, but capillary water will eventually evaporate, particularly on a windy day. When sea water dries up, salt is left behind. Since the seawater was forming bridges between the grains, the salt crystallizes at these points of contact. In this way, salt can keep a sandcastle standing long after the sand has dried. But be careful not to disturb the salt-bonded sand; it’s brittle and collapsible.</p>
<p>To build a strong sandcastle, compact sand and a little water as tightly as you can. I prefer to create a dense mound and then scoop and carve away to reveal the art within. You can also compact the sand into buckets, cups or other molds, and build from the ground up. Just be sure to get the sand dense, and place the mold on a compacted foundation. Hands make for both a great compaction and carving tool, but a shovel or a seashell will allow for more precision. Have fun, and don’t be afraid to get sandy!</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/478599/original/file-20220810-667-8spnjg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Light brown sand with windblown ripples in a panoramic view of desert landscape in Great Sand Dunes National Park, Colorado, USA" src="https://images.theconversation.com/files/478599/original/file-20220810-667-8spnjg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/478599/original/file-20220810-667-8spnjg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/478599/original/file-20220810-667-8spnjg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/478599/original/file-20220810-667-8spnjg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/478599/original/file-20220810-667-8spnjg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/478599/original/file-20220810-667-8spnjg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/478599/original/file-20220810-667-8spnjg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The best sand for sandcastles is closer to mountain areas like Colorado than the beach. Wind and water haven’t yet rounded the ends and edges of the sand grains.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/great-sand-dunes-national-park-colorado-usa-royalty-free-image">Patrick Lienin/Moment via Getty Images</a></span>
</figcaption>
</figure><img src="https://counter.theconversation.com/content/188208/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Joseph Scalia does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>From capillary forces to sand grain shape, the simple mix of sand and water hides the complexity within.Joseph Scalia, Associate Professor of Civil and Environmental Engineering, Colorado State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1825712022-05-23T13:24:25Z2022-05-23T13:24:25ZRising sea levels are driving faster erosion along Senegal’s coast<figure><img src="https://images.theconversation.com/files/463689/original/file-20220517-20-wav7w5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Destroyed buildings along an eroded coastline in Bargny, Senegal.
</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/women-walk-past-destroyed-buildings-along-the-eroded-news-photo/1228661818">Photo by John Wessels / AFP via Getty Images</a></span></figcaption></figure><p>Coastal retreat in West Africa is a pressing problem. The contact between land and sea on coasts produces intense erosion and sedimentation processes. When erosion is more intense than deposits of soil and sand, the sea advances and the coastline retreats. This can be caused by intense storms, coastal works, sand extraction or the rise in sea level.</p>
<p>The United Nations has recently highlighted the impacts associated with <a href="https://www.unep.org/resources/report/sand-and-sustainability-10-strategic-recommendations-avert-crisis">sand mining</a>, a problem with many environmental and social consequences.</p>
<p>Senegal provides an example of coastal erosion. Between 1954 and 2002, the country’s coastline retreated by an average of 2.2 metres per year, <a href="https://doi.org/10.1007/s11852-020-00742-y">reaching three metres per year between 2014 and 2018</a>. This coastal retreat is destroying houses, tourist buildings and fishing infrastructure, and leading to the disappearance of beaches and the loss of agricultural land.</p>
<p>The advance of the sea is also making <a href="https://www.mdpi.com/2073-4441/10/12/1837">groundwater</a> more saline and unsuitable for human consumption and agriculture. In estuarine areas, an increase in salinity affects <a href="https://www.unep.org/resources/report/global-international-waters-assessment-canary-current-giwa-regional-assessment-41">mangroves and fisheries </a>.</p>
<p>It is important to know what is causing this coastal retreat so that responsibilities can be assigned for dealing with it. There are two dimensions, one local and the other global. </p>
<p>At the local level, some human actions can lead to coastal erosion and beach disappearance. The construction of breakwaters, often in response to erosion, alters the way the sea normally moves sand from one place to another. Although breakwaters solve local problems, they may create new ones: sand deposit in one area occurs at the cost of erosion in another. </p>
<p>Another problem in West Africa is illegal mining of coastal sand, mostly for construction. <a href="https://doi.org/10.1038/s41893-022-00857-0">Sand is in demand, and beaches are an easy source of supply</a>. </p>
<p><a href="https://doi.org/10.1007/978-3-319-06388-1_1">At a global level</a>, <a href="https://climateknowledgeportal.worldbank.org/sites/default/files/2018-10/wb_gfdrr_climate_change_country_profile_for_SEN.pdf">this region is highly affected by climate change</a>. A rise in sea level is becoming <a href="https://www.ipcc.ch/site/assets/uploads/2020/11/TGICA_Fact_Sheet_CMIP5_data_provided_at_the_IPCC_DDC_Ver_1_2016.pdf">more and more pronounced </a>. One of the impacts is an increase of coastal erosion, which affects agriculture, fisheries and tourism. </p>
<p><a href="https://link.springer.com/article/10.1007/s11852-020-00742-y">In a recent study</a> we aimed to evaluate shoreline retreat in a 13km section of Senegal’s coast, in the Palmarin peninsula. We were looking for trends over time and causes. </p>
<p>The study showed an increasing retreat of the coastline over dozens of kilometres, with no local human action to justify it. The main cause is climate change. It is likely there will be significant impacts for the environment, the population and economic activities. There is an urgent need to develop an adaptation plan for this area.</p>
<h2>Palmarin, a classic story of climate change</h2>
<p>We chose to study the Palmarin area because it is highly vulnerable to coastal erosion, land flooding and soil salinisation. Shoreline retreat is already intense. <a href="https://cedb.asce.org/CEDBsearch/record.jsp?dockey=0083162">Previous studies</a> showed <a href="http://article.sapub.org/10.5923.j.ms.20170701.01.html">shoreline retreat rates</a> of 1.20m/year in 1982 and 2.20m/year in 1954–2002.</p>
<p>We looked at the period 2005-2018 and compared our results with earlier estimations and measurements. We used as shoreline retreat indicator the sea erosion front. This is the small scarp between the beach and hinterland, which is easily recognisable in aerial photos. We found an increase of retreat to 2.45 m/year in 2005–2010, 2.60 m/year in 2010–2014 and 3.05 m/year in 2014–2018.</p>
<p>We also assessed the risk of coastal retreat in the short and medium term future. </p>
<p>Our short-term estimates showed probable damage to villages, tourist camps and roads. There is also a significant risk that coastal erosion will connect the sea and the intertidal mud flat areas of the Saloum estuary. This would break up the peninsula into several islands, changing the way that erosion evolves, producing a decline of mangroves and thus threatening fishing. <a href="https://www.int-res.com/articles/cr/6/c006p165.pdf">Mangroves are important spawning areas</a>, so erosion affects fishing, an essential economic resource for the local population.</p>
<p>In the studied area there are currently no coastal defences or sand extraction areas. Therefore, coastal erosion cannot be attributed to human actions. On the other hand, <a href="https://www.ipcc.ch/report/ar1/wg1/sea-level-rise/">sea level rise is indisputable</a> and explains what is happening.</p>
<h2>A global responsibility</h2>
<p><a href="https://www.thenewhumanitarian.org/news/2013/02/01/sand-mining-threatens-homes-and-livelihoods-sierra-leone">Lorries removing sand from a beach</a> make for a media-friendly <a href="https://coastalcare.org/2016/01/senegal-president-asks-the-government-to-take-measures-to-stop-illegal-beach-and-dunes-sand-mining-along-senegal-coast/">image</a>, while a gradual rise in sea level by a few millimetres each year is much more subtle. Yet its effects are devastating. The advance of the sea on the coasts of West Africa can affect hundreds of thousands of people.</p>
<p>Action is needed at both global and local levels to mitigate the effects of coastal retreat. </p>
<p>Locally, works that alter coastal dynamics should be avoided and coastal sand mining should be controlled. Many countries already do this. In Senegal the <a href="https://eiti.org/documents/senegals-2016-mining-code">mining code</a> prohibits sea sand extraction, the gendarmerie combat illegal mining and the government conducts studies to find alternatives to sea sand.</p>
<p>But these measures, which may solve local problems, will not halt the current coastal retreat. Strong global action by all countries is essential to mitigate climate change by drastically reducing greenhouse gas emissions.</p>
<p>Local adaptation measures are also necessary to guarantee the future of the region and its inhabitants. Coastal defences are expensive and don’t stop beaches from disappearing. In many places, it will be necessary to consider moving the population away from the coastline to allow the formation of new beaches. Doing so will require large investments and land occupations, and may affect agriculture and biodiversity.</p>
<p>Climate change is a global process, but each country’s responsibilities are different. Therefore, adaptation to its effects must also be global, and its <a href="https://www.ipcc.ch/report/ar6/wg2/downloads/report/IPCC_AR6_WGII_FinalDraft_Chapter09.pdf">financing</a> must be commensurate with those responsibilities. </p>
<p>West African countries must avoid the local causes of coastal retreat. But above all, they should get international support to adapt to the social, environmental and economic problems arising from climate change, a global problem for which they are hardly responsible.</p><img src="https://counter.theconversation.com/content/182571/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Álvaro Enríquez de Salamanca does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Coastal erosion in West Africa is a cause for global concern. The global community must rally to address climate change which is causing the retreat.Álvaro Enríquez de Salamanca, Assistant Professor, Universidad Complutense de MadridLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1691552021-12-26T20:27:14Z2021-12-26T20:27:14ZSlip, slop, slurp! The surprising science of sunscreen, sand and ice cream<figure><img src="https://images.theconversation.com/files/435198/original/file-20211202-25-12jv98a.jpg?ixlib=rb-1.1.0&rect=20%2C8%2C1976%2C1320&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Ahh, summer at the beach! The sun on your face, sand between your toes, an ice cream in your hand. </p>
<p>For scientists young and old, a trip to the beach is also a perfect opportunity to explore the peculiar properties of some fascinating fluids. </p>
<h2>Through thick and thin</h2>
<p>Take sunscreen. When you first squeeze sunscreen from the bottle, it spreads easily over your skin, providing an even protective layer against the Sun’s rays. But once on your skin, sunscreen gains a thicker consistency – it has higher <em>viscosity</em> – preventing it from dripping off. </p>
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Read more:
<a href="https://theconversation.com/explainer-how-does-sunscreen-work-what-is-spf-and-can-i-still-tan-with-it-on-88869">Explainer: how does sunscreen work, what is SPF and can I still tan with it on?</a>
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<p>Viscosity is the ability of a fluid to keep its shape when a force is applied. Sunscreen is what’s called a <em>shear-thinning fluid</em>, which means rubbing it makes its viscosity decrease so it flows more freely.</p>
<p>This effect typically occurs in fluids containing chain-like molecules called polymers. At rest, the polymers are tangled up in an irregular pattern; but when they are pushed around, they rearrange themselves into layers that slide past each other more easily. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/435199/original/file-20211202-23-klmz1g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/435199/original/file-20211202-23-klmz1g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/435199/original/file-20211202-23-klmz1g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/435199/original/file-20211202-23-klmz1g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/435199/original/file-20211202-23-klmz1g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/435199/original/file-20211202-23-klmz1g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/435199/original/file-20211202-23-klmz1g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Sunscreen is a ‘shear-thinning fluid’, which means it flows more easily under pressure.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Shear-thinning fluids are quite common. Ketchup is a classic example: it has high viscosity at rest, making it stick to the sides of the bottle until you shake it so its viscosity decreases and it flows out the nozzle. </p>
<p>When the ketchup lands on your plate, its viscosity increases again so it forms a satisfying dollop. (If this is starting to make your mouth water, you’ll be interested to know that saliva is also a shear-thinning fluid.)</p>
<h2>Footprints in the sand</h2>
<p>The opposite of a shear-thinning fluid is a <em>shear-thickening fluid</em>, a material whose viscosity increases with applied force. </p>
<p>A familiar example is very wet sand: if you pick up a handful, it will flow between your fingers like grainy custard. When you squeeze it, however, the sand becomes firm and, counter-intuitively, appears dry. </p>
<p>This behaviour, called the <em>wet-sand effect</em>, occurs because the compressive force of your hand pushes apart tiny grains of sand, creating space that lets water drain away from the surface. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/435201/original/file-20211202-19-wox09w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/435201/original/file-20211202-19-wox09w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=551&fit=crop&dpr=1 600w, https://images.theconversation.com/files/435201/original/file-20211202-19-wox09w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=551&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/435201/original/file-20211202-19-wox09w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=551&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/435201/original/file-20211202-19-wox09w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=692&fit=crop&dpr=1 754w, https://images.theconversation.com/files/435201/original/file-20211202-19-wox09w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=692&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/435201/original/file-20211202-19-wox09w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=692&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Wet sand is a ‘shear-thickening fluid’: under pressure (like from a footstep) it becomes firmer and less runny.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>The same effect allows you to run on wet sand, producing firm and dry patches where your feet land. But if you stand still and gently wiggle your toes, the wet sand reverts to a liquid state, allowing your feet to sink in – and make a pleasing slurp when you pull them out. </p>
<h2>Newton on the beach</h2>
<p>Simpler fluids, such as water, have a more or less constant viscosity. These are called <em>Newtonian fluids</em>, after Isaac Newton, who first wrote down the mathematical law to describe them in his famous 1687 book Principia. </p>
<p>To understand viscosity, imagine drinking water through a straw. When you suck, you create lower pressure at the top of the straw than the bottom, drawing water upwards.</p>
<p>The fluid near the walls of the straw experiences friction, so it flows more slowly than fluid near the centre. Newton reasoned the fluid separates into thin layers that slide over each other with a relative speed that depends on the applied force. </p>
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Read more:
<a href="https://theconversation.com/kitchen-science-the-many-wonders-of-humble-flour-59310">Kitchen Science: the many wonders of humble flour</a>
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<p>The viscosity measures the amount of friction between these different layers. The greater the viscosity (think of a milkshake), the more force you must apply to suck the fluid up the straw. </p>
<p>Newton’s law of viscosity, as it is known, is a mathematical ideal. No real fluid behaves exactly this way, but common fluids like water, alcohol, and vegetable oil come pretty close. </p>
<p>By contrast, <em>non-Newtonian fluids</em> — including shear-thinning and shear-thickening fluids — do not obey Newton’s law of viscosity: their viscosity changes depending on how much force is applied to them. </p>
<h2>The scoop on ice cream</h2>
<p>Time for some ice cream. Ice cream is a frozen mixture of cream, milk, sugar, and flavourings, but it is the unique behaviour of cream that is responsible for the dribbly joy of really good ice cream. </p>
<p>Cream is peculiar stuff. It is the fat-enriched portion of milk, separated from its watery base. </p>
<p>The resulting <em>emulsion</em> of fat globules and a small amount of liquid gives cream its silkiness. When cream is whisked, the applied force breaks the membranes of the fat globules, which glom together around trapped air, producing a suspension of bubbles and cream: whipped cream. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/435202/original/file-20211202-15-7eey1l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/435202/original/file-20211202-15-7eey1l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/435202/original/file-20211202-15-7eey1l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/435202/original/file-20211202-15-7eey1l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/435202/original/file-20211202-15-7eey1l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/435202/original/file-20211202-15-7eey1l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/435202/original/file-20211202-15-7eey1l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The light, silky texture of ice cream is all due to tiny air bubbles trapped inside little globules of cream.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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</figure>
<p>Whipped cream is a type of non-Newtonian fluid called a <em>Bingham plastic</em>: at rest, it is semi-solid, forming stiff peaks that are perfect for spooning onto strawberries or scones. But under sufficient force, it can flow like a liquid: through the nozzle of a can of instant whipped cream, for example. </p>
<p>As anyone who has made whipped cream by hand knows, the key ingredient is <em>time</em>. The transformation from liquid to semi-solid is caused by applying force over a period of time.</p>
<p>Air bubbles trapped in the cream give ice cream its pillowy softness. In fact, air can make up to 50% of the total volume of ice cream, which explains why it is less dense than water – and why you can use it to make an ice cream float. </p>
<h2>Fantastic fluids</h2>
<p>Non-Newtonian fluids are found in all sorts of useful substances from biofuels to body armour to blood plasma, and there is still much about them to discover. As Isaac Newton said: </p>
<blockquote>
<p>To myself I seem to have been only like a boy playing on the sea-shore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.</p>
</blockquote>
<p>What better way to spend a summer day? </p>
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<strong>
Read more:
<a href="https://theconversation.com/the-story-of-a-wave-from-wind-blown-ripples-to-breaking-on-the-beach-128458">The story of a wave: from wind-blown ripples to breaking on the beach</a>
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<img src="https://counter.theconversation.com/content/169155/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Shane Keating does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A trip to the beach is a perfect opportunity to explore the peculiar properties of some fascinating fluids.Shane Keating, Senior Lecturer in Mathematics and Oceanography, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1541582021-02-10T18:13:47Z2021-02-10T18:13:47ZWe need beach access for everyone, and that includes people with a disability<figure><img src="https://images.theconversation.com/files/382959/original/file-20210208-17-c13196.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2620%2C2136&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock/myphotobank</span></span></figcaption></figure><p>Beach trips are a traditional part of our summers, but for some Kiwis and their family members living with a disability it can be a <a href="https://www.nzherald.co.nz/hawkes-bay-today/news/community-beach-wheelchair-option-explored-by-central-hawkes-bay-district-council/RQ3H4JMJ52IKOHCHH7ESX56KKM/">limiting experience</a>.</p>
<p>Around <a href="https://www.stats.govt.nz/information-releases/disability-survey-2013">1 in 4</a> New Zealanders have a disability. Their <a href="https://www.odi.govt.nz/assets/New-Zealand-Disability-Strategy-files/pdf-nz-disability-strategy-2016.pdf">disability</a> arises not from their impairments but from having to live in world designed by people who think everyone is the same.</p>
<p>It is society, not the individual’s impairment, that is disabling. Thus, it is society that should be enabling.</p>
<p>Examples of enabling measures are seen in efforts to provide beach access for those with disabilities with the installation of <a href="https://www.newshub.co.nz/home/new-zealand/2020/12/takapuna-beach-installs-auckland-s-first-wheelchair-access-mat.html">beach mats</a> for wheelchairs, or the provision of <a href="https://www.nzherald.co.nz/bay-of-plenty-times/news/waihi-beach-has-its-first-beach-wheelchair/G35J5G6ZVKMON7PXZNZVAMZSUY/">beach wheelchairs</a>.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1335493311742660609"}"></div></p>
<p>But after an able-bodied woman suffered a significant leg injury on a beach mat, there are now <a href="https://www.stuff.co.nz/national/300205955/woman-calls-for-removal-of-disability-beach-mat-after-injuring-foot-advocates-defend-it">concerns</a> that Auckland City Council, and other councils across the country, might review the provision of such such mats.</p>
<h2>Disabled rights</h2>
<p>Any such decisions must take the rights of people with disabilities into account. These rights are to be found in international human rights law, and New Zealand’s own law.</p>
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Read more:
<a href="https://theconversation.com/bilingual-road-signs-in-aotearoa-new-zealand-would-tell-us-where-we-are-as-a-nation-150438">Bilingual road signs in Aotearoa New Zealand would tell us where we are as a nation</a>
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<p>The rights of people with disabilities are protected by international human rights law <a href="https://www.ohchr.org/documents/publications/factsheet2rev.1en.pdf">generally</a>, which recognises that everyone is born equal and all have to the right to be free from discrimination.</p>
<p>More dedicated protection is found in the United Nations <a href="https://www.odi.govt.nz/united-nations-convention-on-the-rights-of-persons-with-disabilities/read-the-convention/">Convention on the Rights of Persons with Disabilities 2006</a>, which New Zealand accepted in 2008. </p>
<p>The convention prohibits discrimination on the basis of disability, which it describes as the interaction of people with disabilities and attitudinal and environmental barriers.</p>
<p>It also requires countries should take action to ensure accessibility to a range of spaces and services for people with disabilities on an equal basis with those of non-disabled people.</p>
<h2>Let’s be reasonable</h2>
<p>These rights, like most other rights, must be weighed up with other considerations. A key concept here is <a href="https://www.odi.govt.nz/united-nations-convention-on-the-rights-of-persons-with-disabilities/read-the-convention/">reasonable accommodation</a>.</p>
<p>This means that necessary and appropriate changes should be made that allow people with disabilities to enjoy their rights on an equal basis with others. But such changes should not impose a disproportionate or undue burden.</p>
<p>An <a href="https://www.odi.govt.nz/united-nations-convention-on-the-rights-of-persons-with-disabilities/optional-protocol/read-the-optional-protocol/">Optional Protocol</a> to the convention was also adopted in 2006, which means complaints can be made by individuals to the UN. New Zealand accepted this agreement in 2016.</p>
<p>The <a href="https://www.mfat.govt.nz/assets/Peace-Rights-and-Security/Human-rights/NZ-Human-Rights-Action-Plan.pdf">New Zealand International Human Rights Action Plan 2019-2023</a> also prioritises the country’s leadership role in advocacy for the rights of people with disabilities. </p>
<p>At the domestic level, the <a href="https://www.legislation.govt.nz/act/public/1990/0109/latest/DLM225519.html">New Zealand Bill of Rights Act 1990</a> says everyone has the right to be free from discrimination and the <a href="https://www.legislation.govt.nz/act/public/1993/0082/latest/DLM304475.html">Human Rights Act 1993</a> prohibits discrimination on the grounds of disability.</p>
<p>Domestic law also includes the <a href="https://www.legislation.govt.nz/act/public/1994/0088/49.0/DLM333584.html">Health and Disability Commissioner Act 1994</a>, which established both the role of the Health and Disability Commissioner and a <a href="https://www.hdc.org.nz/your-rights/about-the-code/code-of-health-and-disability-services-consumers-rights/">Code of Health and Disability Services Consumers’ Rights</a>.</p>
<p>One of the purposes of the <a href="https://www.legislation.govt.nz/act/public/2000/0091/latest/DLM80057.html">New Zealand Public Health and Disability Act 2000</a> is to promote the inclusion, societal participation and independence of people with disabilities. The <a href="https://www.legislation.govt.nz/act/public/2008/0064/latest/DLM1404012.html">Disability (United Nations Convention on the Rights of Persons with Disabilities) Act 2008</a> was passed with the aim of giving effect to New Zealand’s obligations under the UN Convention. </p>
<p>The <a href="https://www.odi.govt.nz/assets/New-Zealand-Disability-Strategy-files/pdf-nz-disability-strategy-2016.pdf">New Zealand Disability Strategy 2016-2026</a> guides the work of government agencies on disability issues.</p>
<p>The strategy is informed by the the UN Convention. It is also informed by Te Tiriti o Waitangi, reflecting the cultural importance of whānau and a whānau-centred approach of concepts of family and disability.</p>
<p>The <a href="https://www.odi.govt.nz/disability-action-plan-2/">Disability Action Plan 2019-2023</a> seeks to implement the Disability Strategy and the UN Convention.</p>
<h2>Design public spaces for all</h2>
<p>These legal obligations and policy measures also extend to local authorities. The decisions of such authorities regarding access to public spaces can have a profound impact on the rights of people with disabilities.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/383185/original/file-20210209-15-uo4dmz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A long pathway mat on a beach with a disabled access sign." src="https://images.theconversation.com/files/383185/original/file-20210209-15-uo4dmz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/383185/original/file-20210209-15-uo4dmz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/383185/original/file-20210209-15-uo4dmz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/383185/original/file-20210209-15-uo4dmz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/383185/original/file-20210209-15-uo4dmz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/383185/original/file-20210209-15-uo4dmz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/383185/original/file-20210209-15-uo4dmz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A typical beach mat to help with wheelchair access to the beach.</span>
<span class="attribution"><span class="source">Shutterstock/Tabatha Del Fabbro</span></span>
</figcaption>
</figure>
<p>The provision of beach mats and/or wheelchairs is one practical example that provides people with disabilities with access to the sand and the sea.</p>
<p>But councils can think bigger by also providing mobility spaces that fits all users, appropriately designed footpaths and kerb ramps that lead to accessible seating, shade areas and picnic areas, as well as public toilets that can be used by those with disabilities and their carers.</p>
<p>There is particular room for improvement with the latter and calls for councils to build <a href="https://www.newshub.co.nz/home/new-zealand/2021/01/hamilton-mother-takes-on-mission-to-roll-out-fully-accessible-bathrooms-across-country.html">fully accessible bathrooms</a> to cater to people with multiple or complex disabilities. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-aotearoa-new-zealands-early-polynesian-settlement-should-be-recognised-with-world-heritage-site-status-149981">Why Aotearoa New Zealand's early Polynesian settlement should be recognised with World Heritage Site status</a>
</strong>
</em>
</p>
<hr>
<p>Cost may well be a concern but access to the beach for people with disabilities should not be presented as an optional extra. Ensuring the safety of all beach users will be a paramount consideration, as will the protection of the natural environment.</p>
<p>A diverse and inclusive society means everyone should be treated with dignity and respect at all times. A failure to do so brings its own costs.</p>
<p>New Zealand Herald readers just voted <a href="https://www.whakatane.com/discover/destinations/ohope-beach">Ōhope beach</a> as New Zealand’s <a href="https://www.nzherald.co.nz/nz/new-zealands-best-beach-2021-winner-revealed-ohope-bay-of-plenty/H666CKN4P3E4DFDM2I7PGMJXUA/">best beach</a> in 2021. One of the reasons given was that everyone — from paddleboarders to kitesurfers to those in wheelchairs — is welcome at Ōhope. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1350948601384599555"}"></div></p>
<p>For many New Zealanders, a dip in the ocean on summer days is a simple pleasure but for some, it is simply <a href="https://www.newshub.co.nz/home/new-zealand/2020/12/takapuna-beach-installs-auckland-s-first-wheelchair-access-mat.html">life-changing</a>.</p><img src="https://counter.theconversation.com/content/154158/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Claire Breen does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A trip to the beach is off limits for some people with a disability. We need to change that, and the law supports it.Claire Breen, Professor of Law, University of WaikatoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1501792020-11-24T18:59:51Z2020-11-24T18:59:51ZOne of Australia’s most famous beaches is disappearing, and storms aren’t to blame. So what’s the problem?<figure><img src="https://images.theconversation.com/files/370768/original/file-20201123-15-42rerh.jpg?ixlib=rb-1.1.0&rect=56%2C0%2C7493%2C2795&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source"> Shutterstock</span></span></figcaption></figure><p><a href="https://theconversation.com/explainer-the-wild-storms-that-lash-australias-east-coast-40564">Storms</a> or <a href="https://theconversation.com/our-new-model-shows-australia-can-expect-11-tropical-cyclones-this-season-146318">tropical cyclones</a> usually get the blame when Australia’s beaches suffer severe erosion. But on the New South Wales north coast at Byron Bay, another force is at play.</p>
<p>Over the past six months, tourists and locals have been shocked to see Byron’s famous Main Beach literally <a href="https://www.abc.net.au/news/2020-10-19/yron-bay-emergency-beach-erosion-work-begins-nsw-beaches/12780162">disappearing</a>, inundated with water and debris. In October, lifesavers were forced to temporarily close the beach because they <a href="https://www.theguardian.com/australia-news/2020/oct/20/a-lot-of-the-beach-is-gone-erosion-closes-byron-bays-main-beach">couldn’t get rescue equipment</a> onto the sand. Resident Neil Holland, who has lived in the area for 47 years, told the ABC:</p>
<blockquote>
<p>It’s the first time I’ve seen it this bad in all the time that I’ve been here, and it hasn’t stopped yet. The sand is just being taken away by the metre.</p>
</blockquote>
<p>So what’s happening? To find the answer, we combined a brief analysis of <a href="https://apps.sentinel-hub.com/eo-browser/?zoom=14&lat=-28.63595&lng=153.60191&themeId=DEFAULT-THEME">satellite imagery</a> with previous knowledge about the <a href="https://www.sciencedirect.com/science/article/pii/B9780081029275000230">process behind the erosion</a> and how it has been occurring at <a href="https://www.sciencedirect.com/science/article/pii/S0025322713000807">Byron Bay</a>. The erosion is due to a process known as “<a href="https://www.sciencedirect.com/science/article/pii/B9780081029275000230">headland bypassing</a>”, and it is quite different to erosion from storms.</p>
<figure>
<iframe src="https://player.vimeo.com/video/444063224" width="500" height="281" frameborder="0" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen=""></iframe>
</figure>
<h2>What is headland bypassing?</h2>
<p><a href="https://www.sciencedirect.com/science/article/pii/B9780081029275000230%22%22">Headland bypassing</a> occurs when sand moves from one beach to another around a solid obstruction, such as a rocky headland or cape. This process is mainly driven by wave energy. Along the coast of southeast Australia, waves generate currents that move sand mostly northward along the northern NSW coastline, and on towards Queensland.</p>
<p>However, sand does not flow evenly or smoothly along the coast: when sand arrives at a beach just before a rocky headland, it builds up against the rocks and the beach grows wider. When there is too much sand for the headland to hold, or there’s a change in wave conditions, some sand will be pushed around the headland – <a href="https://www.sciencedirect.com/science/article/pii/S0025322716300780?via%3Dihub">bypassing it</a> – before continuing its journey up the coast. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/king-tides-and-rising-seas-are-predictable-and-were-not-doing-enough-about-it-91318">King tides and rising seas are predictable, and we're not doing enough about it</a>
</strong>
</em>
</p>
<hr>
<p>This large lump of moving sand is called a “sand pulse” or “sand slug”. The sand pulse needs the right wave conditions to move towards the shore. Without these conditions, the beach in front of the pulse is deprived of sand and the waves and currents near the shore erode the beach.</p>
<p>Headland bypassing was first described in the 1940s. However, only about <a href="https://www.wiley.com/en-us/Handbook+of+Beach+and+Shoreface+Morphodynamics-p-9780471965701">20 years ago</a> was it recognised as an important part of the process controlling sand moving along the coast. Since then, with better technology and more data, researchers have studied the process <a href="https://www.sciencedirect.com/science/article/pii/B9780081029275000230">in more detail</a>, and helped to shed light on how headland bypassing might affect long-term coastal planning.</p>
<p>Recent studies have shown wave direction is <a href="https://www.sciencedirect.com/science/article/pii/S0169555X18301375%22%22">particularly important</a> to headland bypassing. Importantly, <a href="https://www.sciencedirect.com/science/article/pii/S0278434315000461">weather patterns that produce waves</a> are affected by <a href="https://theconversation.com/meet-el-ninos-cranky-uncle-that-could-send-global-warming-into-hyperdrive-72360">climate drivers</a> including the El Niño Southern Oscillation and the Interdecadal Pacific Oscillation. So, future changes in the way these drivers behave will affect the waves and currents that move sand along our coast, which in turn affects headland bypassing and beach erosion.</p>
<figure class="align-center ">
<img alt="Man sitting near eroded beach" src="https://images.theconversation.com/files/370979/original/file-20201124-19-15btrs9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/370979/original/file-20201124-19-15btrs9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/370979/original/file-20201124-19-15btrs9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/370979/original/file-20201124-19-15btrs9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/370979/original/file-20201124-19-15btrs9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/370979/original/file-20201124-19-15btrs9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/370979/original/file-20201124-19-15btrs9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Byron Bay’s beaches have badly eroded in recent months.</span>
<span class="attribution"><span class="source">Byron Shire Council</span></span>
</figcaption>
</figure>
<h2>What’s happening at Byron Bay?</h2>
<p>In October and November this year, a large amount of sand was present just north of Cape Byron, from <a href="https://beachsafe.org.au/beach/nsw/byron/byron-bay/wategos">Wategos Beach</a> to <a href="https://beachsafe.org.au/beach/nsw/byron/byron-bay/the-pass">The Pass Beach</a>. As this sand pulse grew, <a href="https://beachsafe.org.au/beach/nsw/byron/byron-bay/clarks">Clarkes Beach</a>, and then <a href="https://beachsafe.org.au/beach/nsw/byron/byron-bay/main-byron-bay">Main Beach</a>, were starved of their usual sand supply and began to erode. </p>
<p>The sand pulse is visible on satellite images from around April 2020. Each month, it slowly moves westward into the bay. As the sand pulse grows, the beach ahead of the pulse gradually erodes. At present Main Beach is at the eroding stage.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/la-nina-will-give-us-a-wet-summer-thats-great-weather-for-mozzies-147180">La Niña will give us a wet summer. That's great weather for mozzies</a>
</strong>
</em>
</p>
<hr>
<p>Similar erosion was observed at Main Beach in the early <a href="http://nsw-coastal-explorer.domorewithmaps.com/documents/BEACH%20BEHAVIOUR%20IN%20RESPONSE%20TO%20CHANGES%20IN%20WIND,%20WAVE%20AND%20TIDAL%20CHARACTERISTICS%20AT%20BYRON%20BAY%20NSW%20-%20INTEGR.pdf">1990s</a>. The beach became wider again from 1995 to 2007. From 2009 onwards, the shoreline erosion slowly began again, and became very noticeable in the past six months.</p>
<p>The effect of sand pulses on beach erosion is not exclusive to Byron Bay. It has been described <a href="https://meridian.allenpress.com/jcr/article-abstract/32/4/863/48588">previously</a> in other locations, such as NSW’s <a href="https://www.tweed.nsw.gov.au/Documents/Environment/Tweed%20Coast/TSC04436_Coastal_Erosion_at_Kingscliff_December_2011.pdf">Kingscliff Beach</a> in 2011. In that case, the erosion risked damaging a nearby holiday park and bowling club. </p>
<figure class="align-center ">
<img alt="Satellite images showing sand movement around Cape Byron" src="https://images.theconversation.com/files/370255/original/file-20201119-17-gmf34j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/370255/original/file-20201119-17-gmf34j.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=455&fit=crop&dpr=1 600w, https://images.theconversation.com/files/370255/original/file-20201119-17-gmf34j.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=455&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/370255/original/file-20201119-17-gmf34j.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=455&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/370255/original/file-20201119-17-gmf34j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=572&fit=crop&dpr=1 754w, https://images.theconversation.com/files/370255/original/file-20201119-17-gmf34j.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=572&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/370255/original/file-20201119-17-gmf34j.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=572&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Satellite images showing sand movement around Cape Byron.</span>
<span class="attribution"><span class="source">Author provided</span></span>
</figcaption>
</figure>
<h2>When will this end?</h2>
<p>Mild waves from the east to northeast, which usually occur from October to April each year, will help some of the sand pulse move onto Clarkes Beach and then further along to Main Beach. This normally happens over several months to a year. But it’s hard to say exactly when the beach will be fully restored. </p>
<p>This uncertainty underscores the need to better <a href="https://www.mdpi.com/2077-1312/6/3/94">forecast these processes</a>. This would help us to predict when bypassing sand pulses will occur and to manage beach erosion. </p>
<p>Climate change is <a href="https://www.sciencedirect.com/science/article/pii/S0921818118301073">expected</a> to affect wave conditions, although the exact impact on the headland bypassing process remains unclear. However, better predictions would allow the community to be informed early about expected impacts, and officials could better manage and plan for future erosion. </p>
<p>Meanwhile, Byron Bay waits and watches – knowing at least that the erosion problem will eventually improve.</p>
<figure class="align-center ">
<img alt="People walking along Main Beach" src="https://images.theconversation.com/files/370705/original/file-20201123-19-1elrzfw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/370705/original/file-20201123-19-1elrzfw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/370705/original/file-20201123-19-1elrzfw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/370705/original/file-20201123-19-1elrzfw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/370705/original/file-20201123-19-1elrzfw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/370705/original/file-20201123-19-1elrzfw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/370705/original/file-20201123-19-1elrzfw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=505&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The sand at Main Beach at Byron Bay, pictured here under good conditions, will eventually return.</span>
<span class="attribution"><span class="source">AAP</span></span>
</figcaption>
</figure><img src="https://counter.theconversation.com/content/150179/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Over the past six months, tourists and locals have been shocked to see Byron’s famous Main Beach literally disappearing. Satellite imagery and local knowledge has revealed what’s going on.Thomas Murray, Research Fellow (Coastal Management), Griffith UniversityAna Paula da Silva, PhD Candidate, Griffith UniversityDarrell Strauss, Senior Research Fellow, Griffith UniversityGuilherme Vieira da Silva, Research Fellow, Griffith UniversityRodger Tomlinson, Director - Griffith Centre for Coastal Management, Griffith UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1324122020-05-03T15:26:47Z2020-05-03T15:26:47ZRoving bandits and looted coastlines: How the global appetite for sand is fuelling a crisis<figure><img src="https://images.theconversation.com/files/320244/original/file-20200312-111249-1iul55j.jpg?ixlib=rb-1.1.0&rect=58%2C76%2C1446%2C1054&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A sand mine in Nepal. Growing urbanization and its need for concrete is fuelling a global sand crisis. </span> <span class="attribution"><span class="source">(Michael Hoffmann)</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Next to water, sand is our most consumed natural resource. The global demand for sand and gravel stands between <a href="https://www.unenvironment.org/news-and-stories/press-release/rising-demand-sand-calls-resource-governance">40 billion and 50 billion tonnes annually</a>, according to the United Nations Environment Program (UNEP), and its <a href="https://doi.org/10.1038/d41586-019-02042-4">scarcity</a> is an emerging global crisis. </p>
<p>The world may <a href="https://www.theguardian.com/global/2018/jul/01/riddle-of-the-sands-the-truth-behind-stolen-beaches-and-dredged-islands">run out of sand</a> if we do not start paying attention to sand as a resource that needs research, management and governance.</p>
<p>The demand for sand is only expected to rise. Sand is also needed to manufacture <a href="https://fivethirtyeight.com/features/how-covid-19-is-wreaking-havoc-on-our-ability-to-make-things-including-vaccines/">medical-grade glass vials</a>, which are used to hold vaccines. The industry already faced shortages even before researchers began developing a coronavirus vaccine. And <a href="https://www.theguardian.com/us-news/2019/oct/25/surfside-florida-beaches-climate-crisis-sea-levels">conflicts over sand</a> are emerging in Florida and other seemingly sand-rich areas. </p>
<p>But urbanization and its need for <a href="https://www.rgs.org/schools/teaching-resources/why-is-sand-a-powerful-natural-resource/">concrete, land infill, asphalt and glass</a> is fuelling sand exploitation the most. The global urban population, expected to grow to 5.2 billion by 2030 from 4.4 billion today, will sustain the <a href="https://www.un.org/en/events/citiesday/assets/pdf/the_worlds_cities_in_2018_data_booklet.pdf">global construction boom</a>, where sand is the key ingredient for concrete. </p>
<p>As sand markets boom, entrepreneurs, organized crime and other groups have emerged to cash in, often using cheap labour and driving widespread habitat destruction and coastal, riverbank and delta erosion. </p>
<h2>Violent economies, precarious work</h2>
<p>Work conditions for sand miners vary starkly. In Cambodia and southwest China, highly mechanized sand mines offer little local employment. In Nepal, labour-intensive sand mines may employ hundreds of people. And, in Myanmar, households living along rivers may be involved in informal river sand collection. </p>
<p>Sand mining can be dangerous. Miners may drown as they harvest sand by hand underwater, and hundreds of sand miners, grassroots activists, journalists, police officers, government officials and others have been <a href="https://www.youtube.com/watch?v=f12SSCUfOhk">killed in clashes over sand</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/320184/original/file-20200312-111253-1lwdjx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/320184/original/file-20200312-111253-1lwdjx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/320184/original/file-20200312-111253-1lwdjx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/320184/original/file-20200312-111253-1lwdjx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/320184/original/file-20200312-111253-1lwdjx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/320184/original/file-20200312-111253-1lwdjx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/320184/original/file-20200312-111253-1lwdjx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Workers empty a sand barge near Phnom Penh, Cambodia.</span>
<span class="attribution"><span class="source">(Lukas Van Arragon)</span></span>
</figcaption>
</figure>
<p>A diverse set of players including <a href="https://doi.org/10.1177/1477370816649627">organized crime</a> are involved in the sand mining industry. <a href="https://doi.org/10.1126/science.1122804">Roving bandits</a> hunt for sand deposits to dredge, and operations may be hidden from port authorities using <a href="https://www.technologyreview.com/s/614689/ghost-ships-crop-circles-and-soft-gold-a-gps-mystery-in-shanghai/">high-tech GPS spoofing devices</a>. Local mafia-like structures — in <a href="https://www.uclpress.co.uk/products/109083">India</a> and likely in at least 70 countries — control entire sand mines and districts. </p>
<p>We know these sites are characterized by violence, secrecy and a lack of trust, but <a href="https://doi.org/10.1080/01924036.2015.1082486">sand’s shadow economy</a> remains largely unknown. This limits our understanding of the financial flows that fuel sand mining, the barriers to trade regulation and sand governance, and the criminal aspects of sand operations.</p>
<h2>Carbon emissions, land loss</h2>
<p>Unsustainable or illegal sand extraction from marine, coastal and freshwater ecosystems has led to serious sustainability challenges, including carbon emissions and land loss. These environmental impacts will likely be further compounded: data on sand extraction are incomplete, with global sand imports exceeding global exports. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/321182/original/file-20200318-60894-iz7o3l.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/321182/original/file-20200318-60894-iz7o3l.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/321182/original/file-20200318-60894-iz7o3l.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=329&fit=crop&dpr=1 600w, https://images.theconversation.com/files/321182/original/file-20200318-60894-iz7o3l.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=329&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/321182/original/file-20200318-60894-iz7o3l.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=329&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/321182/original/file-20200318-60894-iz7o3l.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=413&fit=crop&dpr=1 754w, https://images.theconversation.com/files/321182/original/file-20200318-60894-iz7o3l.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=413&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/321182/original/file-20200318-60894-iz7o3l.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=413&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Global sand trade, as reported by exporting and importing countries.</span>
<span class="attribution"><span class="source">(UN Comtrade)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The case of sand exports <a href="https://doi.org/10.1080/24694452.2018.1541401">from Cambodia</a> illustrates this. Singapore imported 80.2 million tonnes of sand from Cambodia between 2007 and 2016, representing a third of the city-state’s sand imports. Yet, most of this trade is absent in Cambodia’s official trade logs — Cambodia registered only 2.77 million tonnes of sand exports to Singapore, disguising how important this commodity is to the country’s development. </p>
<p>Infrastructure demands for housing and development fuels the concrete sector, which now contributes <a href="https://www.chathamhouse.org/publication/making-concrete-change-innovation-low-carbon-cement-and-concrete">eight per cent of global carbon dioxide emissions</a>. This is a serious issue from a carbon emissions perspective. That means sand, by way of concrete, is tied to our climate futures — and vice versa, as the recent interest in mining the sand emerging from <a href="https://doi.org/10.1038/s41893-018-0218-6">Greenland’s melting ice sheet</a> demonstrates. </p>
<p>Scientists have also confirmed <a href="https://doi.org/10.1038/s41893-019-0455-3">river bank instability</a> from sand mining in the Mekong, Yangtze and other large rivers. Sand dredging impacts river flow, erosion levels and aquatic habitats. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/331531/original/file-20200429-51495-25qp01.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/331531/original/file-20200429-51495-25qp01.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=459&fit=crop&dpr=1 600w, https://images.theconversation.com/files/331531/original/file-20200429-51495-25qp01.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=459&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/331531/original/file-20200429-51495-25qp01.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=459&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/331531/original/file-20200429-51495-25qp01.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=577&fit=crop&dpr=1 754w, https://images.theconversation.com/files/331531/original/file-20200429-51495-25qp01.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=577&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/331531/original/file-20200429-51495-25qp01.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=577&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Riverbank erosion along the Mekong River, Cambodia.</span>
<span class="attribution"><span class="source">(Lukas Van Arragon)</span></span>
</figcaption>
</figure>
<p>In Myanmar, <a href="https://www.reuters.com/article/us-myanmar-sand-singapore-insight/as-myanmar-farmers-lose-their-land-sand-mining-for-singapore-is-blamed-idUSKBN20R0C1">river-bed farmers</a> are losing their land as sand mining intensifies. Across the Mekong Delta, people are struggling to find fish, which are affected by the noise of sand dredging, as <a href="https://www.nationalgeographic.com/news/2018/03/vietnam-mekong-illegal-sand-mining/">homes and roads further crumble into rivers</a>. </p>
<h2>Mobilizing a sand agenda</h2>
<p>An important starting point for mobilizing a sand agenda is the <a href="https://wedocs.unep.org/bitstream/handle/20.500.11822/28163/SandSust.pdf?sequence=1&isAllowed=y">2019 UNEP sand governance</a> report, focusing on accountability and transparency in sand value chains. Global sand governance is critical. </p>
<p><a href="https://www.gatesnotes.com/Energy/Buildings-are-good-for-people-and-bad-for-the-climate">Changing how we build our cities</a> is another part of how we face the sand and climate crises. We need to ask ourselves why we have been so seduced by concrete. If we do not change our habits, and encourage the development of “green concrete” and alternative building materials or innovations such as using bacterial species in <a href="https://doi.org/10.1080/19648189.2020.1713899">bio-concrete</a>, the world built from sand may be pulled down by its own weight. </p>
<p>To further mobilize a sand agenda, researchers and campaigners could focus on narratives that draw on the climate crisis or other <a href="https://www.theguardian.com/environment/2018/aug/31/trade-of-coastal-sand-is-damaging-wildlife-of-poorer-nations-study-finds">ecological dimensions</a>, such as directing attention to how sand dredging is linked to landslides and poorer water quality, or how sand infill leads to the <a href="https://www.tecsea.info/post/destruction-of-critical-urban-wetland-risks-the-end-of-urban-farming-and-wastewater-treatment">loss of wetland habitat</a>. </p>
<p>Others could unpack labour regimes, advocate for better working conditions, or explore the involvement of political groups in financing sand extraction. We need to delve deeper into how the sand mining sector relies on cheap labour, fast-moving money, some of it illicit, and criminal activities. </p>
<p>This sand agenda, through the consideration of working conditions and ecological dimensions, enables us to imagine a global future that is greener and more just.</p><img src="https://counter.theconversation.com/content/132412/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Melissa Marschke received funding from the Research Impact Competition, FSS, Ottawa, which funded a Fall 2019 workshop that all authors participated in. We greatly appreciate Vince Beiser's engaging sand plenary, which sparked many fruitful discussions.</span></em></p><p class="fine-print"><em><span>Jean-François Rousseau receives funding from the Research Group Program at the University of Ottawa, and from SSHRC (Insight Development Program). </span></em></p><p class="fine-print"><em><span>Laura Schoenberger receives funding from Canada's Banting Fellowship</span></em></p><p class="fine-print"><em><span>Michael Hoffmann receives funding from DFG (German Research Foundation).</span></em></p>As sand markets boom, entrepreneurs, organized crime and others are cashing in — leaving widespread environmental damage in their wake.Melissa Marschke, Associate Professor, School of International Development and Global Studies, L’Université d’Ottawa/University of OttawaJean-François Rousseau, Assistant Professor, School of International Development and Global Studies, L’Université d’Ottawa/University of OttawaLaura Schoenberger, Postdoctoral research fellow, School of International Development and Global Studies, L’Université d’Ottawa/University of OttawaMichael Hoffmann, Research officer, Centre for Interdisciplinary Regional Studies (ZIRS), Martin Luther University Halle-WittenbergLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1326882020-03-02T16:16:53Z2020-03-02T16:16:53ZHalf of world’s sandy beaches could disappear due to sea level rise by 2100<figure><img src="https://images.theconversation.com/files/318022/original/file-20200302-18308-w8cexq.jpg?ixlib=rb-1.1.0&rect=0%2C233%2C3985%2C2300&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A crowded Copacabana Beach in Rio de Janeiro, Brazil.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/rio-de-janeiro-brazil-aerial-view-1293099220">R.M. Nunes/Shutterstock</a></span></figcaption></figure><p>Up to half of the world’s sandy beaches are at risk of disappearing by the end of this century if no action is taken to limit greenhouse gas emissions. That’s according to <a href="https://nature.com/articles/s41558-020-0697-0">a new study, published in Nature Climate Change</a>. Even assuming a better outcome for action on climate change, where global emissions peak around 2040, well over one-third (37%) of the world’s beaches would be lost by 2100.</p>
<p>Researchers had previously analysed satellite images showing shoreline change from 1984 to 2016. They found that a quarter of sandy beaches worldwide had already <a href="https://www.nature.com/articles/s41598-018-24630-6">eroded at a rate of more than 0.5m per year</a>, shedding over <a href="https://www.nature.com/articles/s41598-018-30904-w">28,000 square kilometres of land</a> to the sea.</p>
<p>The rate at which sea levels are rising is accelerating by <a href="https://www.pnas.org/content/115/9/2022.short">about 0.1mm per year each year</a>. But sea level rise won’t be even across the globe. The term “sea level” can be misleading – the sea surface is not flat. Much like the atmosphere, it has high and low pressure areas which create mounds and troughs. Some of these are created by major currents, so changes that will take place as the oceans warm will change the topography of the sea surface. Some areas will receive less than the predicted average sea level rise, but many will see more.</p>
<p>More than 60% of sandy beaches in Gambia and Guinea-Bissau may be lost to erosion by rising seas, while Australia is expected to lose nearly 12,000 km of sandy coastline. For small island states such as Kiribati, the Marshall Islands and Tuvalu, losing 300m of land – as predicted for some – would be catastrophic.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/318059/original/file-20200302-18295-1sxqkml.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/318059/original/file-20200302-18295-1sxqkml.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/318059/original/file-20200302-18295-1sxqkml.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/318059/original/file-20200302-18295-1sxqkml.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/318059/original/file-20200302-18295-1sxqkml.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/318059/original/file-20200302-18295-1sxqkml.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/318059/original/file-20200302-18295-1sxqkml.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">An aerial view of Funafuti atoll, Tuvalu, shows the airstrip of Vaiaku international airport. There is little space for the coast to retreat as sea levels rise.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/tuvalu-under-wing-airplane-aerial-view-1221046468">Maloff/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Nowhere to go</h2>
<p>Sandy beaches occupy more than one-third of the global coastline and of all the different types of beaches, sandy beaches are the most heavily used by people. Many coastal areas have been built on, for industry, housing and tourist resorts. </p>
<p>These “softer” parts of the shoreline have always been at the mercy of ocean storms and the tides. But the predicted sea level rise on top of these daily inundations pushes the boundary between coast and sea inland, a process known as coastal retreat. </p>
<p>The build-up of people and concrete at the landward fringe of sandy beaches has created an abrupt barrier to coastal retreat, preventing beaches from moving inland as sea levels rise. Instead, sandy stretches of coastline are at risk of being eroded and washed away entirely.</p>
<p>Warming seas also promise more intense and frequent storms, which are capable of moving entire beaches overnight. Porthleven Beach in Cornwall, UK <a href="https://theconversation.com/why-beaches-lose-their-sand-and-then-suddenly-reappear-77503">lost all of its sand</a> during a storm in January 2015, to be returned by the tide a few days later.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"563449499339591681"}"></div></p>
<p>Soft sandy beaches are continuously moved by waves and currents – depleting them in certain areas and depositing them in others. This transport of sand is normal, but the combined force of higher sea levels and stronger storms could spell extinction for many beaches.</p>
<p>All of this is very worrying for the millions of people who call these regions home. The world’s sandy coastlines tend to be densely populated, and are <a href="https://journals.plos.org/plosone/article%3Fid%3D10.1371/journal.pone.0118571">becoming more so</a> over time. In <a href="https://www.sciencedirect.com/science/article/pii/S0921818113002026?via%3Dihub">other research</a>, it was found that sea level rise by 0.8m could erase 17,000 square km of land and force up to 5.3 million people to migrate, with an associated cost of USD$300-1,000 billion globally. In <a href="https://link.springer.com/article/10.1007%2Fs10113-011-0249-2">Africa alone</a>, up to 40,000 people per year could be forced to migrate due to land loss by coastal erosion if no adaptive measures are in place by 2100.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/climate-change-sea-level-rise-could-displace-millions-of-people-within-two-generations-116753">Climate change: sea level rise could displace millions of people within two generations</a>
</strong>
</em>
</p>
<hr>
<p>But it isn’t just climate change. Humans are actively accelerating coastal erosion by removing sand from beaches in enormous quantities and at much faster rates than it can be naturally renewed. Gravel and sand is extracted from rivers and on beaches for use in construction – and at a faster rate than fossil fuel extraction in some areas. </p>
<p>Coastal ecosystems that bind and trap sediment, like mangrove swamps, are also being destroyed. The world <a href="https://www.iucn.org/sites/dev/files/content/documents/mangroveloss-brief-4pp-19.10.low_.pdf">lost almost 10,000 square kilometres</a> of these habitats between 1996 and 2016. Meanwhile, sediment supply to the coast is also affected by building dams and irrigation systems upstream.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/318064/original/file-20200302-18279-17jg971.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/318064/original/file-20200302-18279-17jg971.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/318064/original/file-20200302-18279-17jg971.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/318064/original/file-20200302-18279-17jg971.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/318064/original/file-20200302-18279-17jg971.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/318064/original/file-20200302-18279-17jg971.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/318064/original/file-20200302-18279-17jg971.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Mangroves are effective buffers against storms and help trap more sand around the coast.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/tanaman-bakau-shrub-small-tree-that-1541915537">Ibenk_88/Shutterstock</a></span>
</figcaption>
</figure>
<p>Sea level rise is inevitable, but <a href="https://theconversation.com/sea-level-rise-is-inevitable-but-what-we-do-today-can-still-prevent-catastrophe-for-coastal-regions-124129">how bad it will be is still not certain</a>. Replenishing the most endangered beaches by pumping sand onto them – a process called “coastal nourishment” – <a href="https://www.sciencedirect.com/science/article/pii/S0921818113002026?via%3Dihub">could cost USD$65–220 billion in total</a>, but that’s still less than one-fifth of the economic cost of taking no action at all on sea level rise. It could reduce land loss by up to 14%, lower the number of people that might be forced to migrate by up to 68%, and shrink the cost of forced migration by up to 85% by 2100. </p>
<p>Even “<a href="https://nature.com/articles/s41558-020-0697-0">moderate emission mitigation policy</a>”, as the new study calls it, in which global emissions peak around 2040, could prevent 40% of the landward retreat of shorelines by 2100. On average, this would save more than 40m width of sandy beach around the world, from an average loss of around 250m.</p>
<p>Coastal nourishment can have its own ecological problems, so it would have to be done with careful attention to the local environment. But much of what needs to be done to save the world’s sandy beaches lies within our grasp already – if we can just reduce the rate at which we’re consuming sand and burning fossil fuels. By doing that – and expanding and protecting coastal habitats – the terrible predictions from this new research might never come to pass.</p>
<hr>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/263883/original/file-20190314-28475-1mzxjur.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/263883/original/file-20190314-28475-1mzxjur.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=140&fit=crop&dpr=1 600w, https://images.theconversation.com/files/263883/original/file-20190314-28475-1mzxjur.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=140&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/263883/original/file-20190314-28475-1mzxjur.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=140&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/263883/original/file-20190314-28475-1mzxjur.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=176&fit=crop&dpr=1 754w, https://images.theconversation.com/files/263883/original/file-20190314-28475-1mzxjur.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=176&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/263883/original/file-20190314-28475-1mzxjur.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=176&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em><a href="https://theconversation.com/imagine-newsletter-researchers-think-of-a-world-with-climate-action-113443?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=Imagineheader1132688">Click here to subscribe to our climate action newsletter. Climate change is inevitable. Our response to it isn’t.</a></em></p><img src="https://counter.theconversation.com/content/132688/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Simon Boxall receives funding from NERC and the EU. </span></em></p><p class="fine-print"><em><span>Abiy S. Kebede does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Sandy beaches are densely populated and occupy more than one third of the global coastline.Simon Boxall, Senior Lecturer in Ocean and Earth Science, University of SouthamptonAbiy S. Kebede, Lecturer in Flood and Coastal Engineering, Brunel University LondonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1263232019-12-19T13:52:00Z2019-12-19T13:52:00ZWhere does beach sand come from?<figure><img src="https://images.theconversation.com/files/307544/original/file-20191217-58292-121izfm.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4052%2C2692&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">This started as a mountain range.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/white-sand-on-beach-dunes-summertime-29294035">Bas Meelker/Shutterstock.com</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
<hr>
<blockquote>
<p><strong>Where does beach sand come from? – Sly M., age 6, Cambridge, Massachusetts</strong></p>
</blockquote>
<hr>
<p>There’s more to beach sand than meets the eye. It has stories to tell about the land, and an epic journey to the sea. That’s because mountains end their lives as sand on beaches. </p>
<p>Over time, mountains erode. The mud, sand, gravel, cobbles and boulders they shed are washed into streams, which come together to form rivers. As they flow down to the sea, all this sediment is ground up and worn down in nature’s version of a rock tumbler. </p>
<p>Big rocks break down into smaller pieces, so most of what reaches the sea is mud. These silt and clay particles are too small to perceive with the naked eye. But you can see individual grains of sand, which are just bigger bits of rock. </p>
<p>Next time you’re at the beach, pick up a handful of sand and look closely at it. Are all the grains the same color, or a rainbow assortment? Are they jagged and angular, or smooth and round? </p>
<p>Different colors of sand come from different minerals, like khaki <a href="https://en.wiktionary.org/wiki/feldspar#/media/File:Feldspar_1659.jpg">feldspar</a>, smoky white <a href="https://en.wikipedia.org/wiki/Quartz#/media/File:Quartz,_Tibet.jpg">quartz</a>, green <a href="https://geology.com/minerals/olivine.shtml">olivine</a> or black <a href="https://en.wikipedia.org/wiki/Basalt#/media/File:BasaltUSGOV.jpg">basalt</a>. The mix of colors in beach sand tells you what kinds of rocks produced it. </p>
<p>The shape of sand grains also provides clues about where they come from. Angular grains of the same type of sand have not traveled as far as smooth round grains, which have been more worn down. And weak rocks break down to mud faster than hard rocks, so sand tends to be made of the harder types that break down slowly. </p>
<p>About a tenth of the supply of sediment that reaches the sea is sand. These particles are between about half a millimeter and 2 millimeters in size – roughly as thick as a penny. These particles are large enough that they don’t flow right out to the deep sea. </p>
<p>But the beach is just a temporary stop for sand. Big waves pull it offshore, and smaller waves push it along the coast. So keeping a beach nourished with sand is essential for keeping it sandy. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/5ZBeMzWMubA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Many beach towns spend millions of dollars to rebuild eroded beaches with new sand.</span></figcaption>
</figure>
<p>Yet today many beaches are starving. Many dams trap the sand that flows down rivers, piling it up in reservoirs. All in all, human activity has cut off about <a href="http://dx.doi.org/10.1126/science.1109454">half the sand</a> that would otherwise end up on the world’s beaches. </p>
<p>But humans haven’t turned the waves off, so as beach sand washes away and isn’t replenished, the shoreline erodes. That means that many beaches around the world are shrinking, slowly but surely. </p>
<p>So next time you dig your toes into beach sand think about the epic journey it took to arrive beneath your feet. Take a moment to think about where the sand came from and where it’s going. </p>
<hr>
<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>. Please tell us your name, age and the city where you live.</em></p>
<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/126323/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David R. Montgomery does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Sand may seem abundant when your toes are buried in it, but it’s becoming scarce along many coastlines around the world.David R. Montgomery, Professor of Earth and Space Sciences, University of WashingtonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1235462019-09-22T09:14:36Z2019-09-22T09:14:36ZAncient humans may have made patterns and sculptures on South Africa’s beaches<figure><img src="https://images.theconversation.com/files/293200/original/file-20190919-22446-voc66e.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A rock surface containing a circular pattern with a central depression. The scale bar = 10 cm.</span> <span class="attribution"><span class="source">Images modified from: Helm, C.W.; Cawthra, H.C.; De Vynck, J.C.; Helm, C.J.; Rust, R.; Stear. W. Patterns in the Sand: A Pleistocene hominin signature along the South African coastline? Proceedings of the Geologists’ Association (2019)</span></span></figcaption></figure><p>One of the first things many kids – or even adults – may do when they are on a beach or dune is to make patterns in the sand, or sculptures in the form of sandcastles.</p>
<p>Many generations of humans have enjoyed these activities. But until now there has been no reported evidence to suggest how far back in human history this may have occurred. Now my colleagues and I believe we may have <a href="https://doi.org/10.1016/j.pgeola.2019.08.004">found such evidence</a> at sites along South Africa’s Cape south coast. </p>
<p>Southern Africa boasts <a href="https://www.mdpi.com/2076-0752/2/1/6">an extensive record of palaeo-art</a>, and South Africa’s Cape south coast, stretching eastward along the coast from Cape Town, contains one of the richest <a href="https://www.researchgate.net/publication/285273001_Stone_Age_People_in_a_Changing_South_African_Greater_Cape_Floristic_Region">Middle Stone Age archaeological records</a> in the world. This includes <a href="https://science.sciencemag.org/content/334/6053/219">an engraved piece of ochre</a> and the <a href="https://www.nature.com/articles/s41586-018-0514-3">oldest reported example of rock painting</a>. Evidence suggests that the area may have been critical to <a href="https://www.nature.com/articles/nature06204">the survival</a> of the human species. </p>
<p>This coastal region now contains extensive aeolianites (cemented dune deposits) and cemented foreshore deposits. These rocks are the cemented remains of the dune and beach surfaces that existed when our distant ancestors and many other vertebrates were <a href="https://www.livescience.com/40311-pleistocene-epoch.html">making tracks</a> in the region in the Middle-Late Pleistocene, approximately 158,000 to 70,000 years ago. We know the ages of the rocks from <a href="https://doi.org/10.1016/j.quascirev.2010.10.003">the results</a> of previous <a href="https://www.sciencedirect.com/science/article/pii/S0031018207004476?">dating studies</a>. </p>
<p>It may seem that tracks and patterns made in the sand are ephemeral, destined to be covered by the effects of the next wind storm or tide. However, perhaps surprisingly, many of these records are preserved, ready to be identified when they are re-exposed through cliff collapse or through forces of erosion. Our team has identified more than <a href="https://doi.org/10.1016/j.quascirev.2019.07.039">140 vertebrate tracksites</a> along this coastline. For example, as many as 40 footprints made by hominins travelling down a dune surface, and estimated as being 90,000 years old, <a href="https://www.nature.com/articles/s41598-018-22059-5">were identified</a> at one site by members of our research team in 2016. </p>
<p>So, given that we know humans moved across these landscapes, we wondered whether there might also be evidence of other forms of human activity on these surfaces of sand, such as patterns, symbols, sculptures, or foraging. If so, could such ancient canvases have left evidence of human activity that can be discerned and interpreted today? Indeed, could such evidence form a previously undocumented form of Middle Stone Age hominin expression and activity? Our findings suggest the answer to these questions may be “yes”. </p>
<h2>A plethora of patterns</h2>
<p>At one site we found a large almost perfectly circular groove, along with a depression in the centre of the circle. Beside this feature was a pair of oval shapes that may represent knee impressions. If this circle was generated by a human, then a possible mechanism could have involved the use of a forked stick, in the same way that a compass is used by kids in maths classes. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/293202/original/file-20190919-22408-r85cy1.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/293202/original/file-20190919-22408-r85cy1.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=722&fit=crop&dpr=1 600w, https://images.theconversation.com/files/293202/original/file-20190919-22408-r85cy1.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=722&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/293202/original/file-20190919-22408-r85cy1.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=722&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/293202/original/file-20190919-22408-r85cy1.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=908&fit=crop&dpr=1 754w, https://images.theconversation.com/files/293202/original/file-20190919-22408-r85cy1.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=908&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/293202/original/file-20190919-22408-r85cy1.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=908&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The author demonstrates how a forked stick may have been used by a kneeling human to create a circular pattern in the sand.</span>
<span class="attribution"><span class="source">Linda Helm</span></span>
</figcaption>
</figure>
<p>Other patterns included groove features beside possible human footprints, and a “hashtag” pattern that <a href="http://dx.doi.org/10.1126/science.1211535">resembles known palaeo-art in the region</a>. We also identified two possible animal images, one of which may conceivably have taken the form of a sculpture of a sting-ray. We have proposed a new term to describe patterns made in sand by humans, which become lithified over time through a natural cementation process: ammoglyph (“ammos” being Greek for “sand”, and “glyph” being Greek for a carving, image or symbol).</p>
<p>If our interpretations are accurate, these findings represent two important things. Firstly, evidence of a human presence on these ancient dunes and beaches is more substantial than has been thought. Secondly, this evidence would buttress that of other avenues <a href="https://www.nature.com/articles/nature06204">of research</a> that <a href="https://www.sciencedirect.com/science/article/pii/S0047248404001307?via%3Dihub">attest to</a> the <a href="https://science.sciencemag.org/content/325/5942/859">cognitive abilities</a> of early humans <a href="https://www.ncbi.nlm.nih.gov/pubmed/23135405">in this region</a>.</p>
<h2>Varying interpretations</h2>
<p>There is a multitude of lines, grooves, patterns and shapes on these rock surfaces. </p>
<p>One of our challenges therefore lay in identifying whether a hominin “signature” could reasonably be inferred among this plethora of forms. We outlined other possible agents that may have caused such patterns (such as wind, water, fossil roots and branches, and traces made by invertebrates, reptiles, birds and other mammals). We also considered how to distinguish between ancient patterns made in sand and more recent patterns etched in rock – that is, graffiti.</p>
<p>In some of the cases we described we simply pointed out features that appeared puzzling, that may possibly have been created by humans, but where other causes could not be reasonably excluded. One site contained patterns that we had never encountered before, and that do not appear anywhere in the ichnological (trace fossil) literature. After due consideration we interpreted this as possibly representing a seal tracksite, and will be reporting on this elsewhere. </p>
<p>In other cases, such as the circular feature with the central depression, the presence of grooves beside possible human footprints, and the “hashtag” pattern, the evidence for a human origin appeared more compelling. However, we took a cautious approach, acknowledging that absolute certainty is elusive. </p>
<h2>Next steps</h2>
<p>Samples have been taken for dating, adjacent to a number of the sites we described. We eagerly await these results. Non-invasive imaging studies may aid in the investigation of the rocks with patterns that suggest foraging behaviour. </p>
<p>We hope that other scientists will critically examine the findings and interpretations that we have presented. Recognising that ancient sand surfaces were not all “perishable”, but that some of them have preserved an extraordinary record of what transpired on them, suggests a previously under-appreciated means of interpreting ancient human expression. </p>
<p>The resulting search for ammoglyphs on the Cape south coast has the potential to become a new field of study, at a meeting point of archaeology, art, ichnology, palaeoanthropology, pattern recognition and sedimentology.</p><img src="https://counter.theconversation.com/content/123546/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Charles Helm does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Given that we know humans moved across these landscapes, we wondered whether there might also be evidence of other forms of human activity on these surfaces of sand.Charles Helm, Research Associate, African Centre for Coastal Palaeoscience, Nelson Mandela UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/971642018-06-06T10:37:16Z2018-06-06T10:37:16ZMicroplastics may heat marine turtle nests and produce more females<figure><img src="https://images.theconversation.com/files/221652/original/file-20180604-175438-1xw21lj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Green sea turtle. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/loggerhead-turtle-caretta-421631590">Miroslav Halama/shutterstock.com</a></span></figcaption></figure><p>Have you ever considered that small pieces of plastic less than 5 millimeters long, or smaller than a pencil eraser head, called microplastics, can affect large marine vertebrates like sea turtles?</p>
<p><a href="https://scholar.google.com/citations?user=REJWJQgAAAAJ&hl=en&oi=ao">My research team</a> first discovered this disturbing fact when we started to quantify the amount and type of microplastic at loggerhead nesting grounds in the northern Gulf of Mexico, between St. Joseph State Park and Alligator Point in Florida.</p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/221654/original/file-20180604-175414-2iexaq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/221654/original/file-20180604-175414-2iexaq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/221654/original/file-20180604-175414-2iexaq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/221654/original/file-20180604-175414-2iexaq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/221654/original/file-20180604-175414-2iexaq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/221654/original/file-20180604-175414-2iexaq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/221654/original/file-20180604-175414-2iexaq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Mircoplastic littering the beach.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/microplastics-on-beach-1085783144?src=fdLKSjkHNqW4WQvXzINYZg-1-11">Loretta Sze/shutterstock.com</a></span>
</figcaption>
</figure>
<p>Microplastics, which are created by the breakdown of larger plastic pieces into smaller ones, or manufactured as <a href="https://theconversation.com/tiny-beads-big-problem-easy-fix-why-scientific-evidence-supports-a-ban-on-microbeads-42511">microbeads</a> or fibers for consumer products, can change the composition of sandy beaches where marine turtles nest. Marine turtles, which are listed under the <a href="https://www.fws.gov/endangered/laws-policies/">Endangered Species Act</a>, lay their eggs in coastal areas, and the environment in which their eggs incubate can influence hatching success, the gender and size of hatchlings. </p>
<p>In particular, the sex of marine turtle eggs is determined by the sand temperature during egg incubation. Warmer sand produces more females and cooler sand, more males. Temperatures between approximately 24-29.5 degrees C produce males and above 29.5 to 34 degrees C, females. Since plastics warm up when exposed to heat, when combined with sand, microplastics may increase the sand temperature, especially if the pigment of the plastic is dark. This could potentially affect the nesting environment of marine turtles, biasing the sex ratio of turtles toward producing only females and affecting the future reproductive success of the species. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/221780/original/file-20180605-119850-982dvu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/221780/original/file-20180605-119850-982dvu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/221780/original/file-20180605-119850-982dvu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/221780/original/file-20180605-119850-982dvu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/221780/original/file-20180605-119850-982dvu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/221780/original/file-20180605-119850-982dvu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/221780/original/file-20180605-119850-982dvu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A nest filled with sea turtle eggs.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/sea-turtle-eggs-577336417?src=xzXkXrxjFfDT1FswsqDB7Q-2-84">Kalaeva/shutterstock.com</a></span>
</figcaption>
</figure>
<p>Coastal areas and consequently marine turtle nesting environment exposed to microplastic may also be harmed by toxic chemicals that leach out of the microplastics when they are heated. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/221781/original/file-20180605-119875-1mqi4sk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/221781/original/file-20180605-119875-1mqi4sk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/221781/original/file-20180605-119875-1mqi4sk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/221781/original/file-20180605-119875-1mqi4sk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/221781/original/file-20180605-119875-1mqi4sk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1131&fit=crop&dpr=1 754w, https://images.theconversation.com/files/221781/original/file-20180605-119875-1mqi4sk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1131&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/221781/original/file-20180605-119875-1mqi4sk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1131&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Newly hatched baby loggerhead turtle emerge from their nests and head straight toward the ocean.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/newly-hatched-baby-loggerhead-turtle-toward-150163562">foryouinf/shutterstock.com</a></span>
</figcaption>
</figure>
<p>Given the potential impacts of microplastic on marine turtle incubating environment, we did a study to determine the microplastic exposure of the 10 most important nesting sites in Florida for the Northern Gulf of Mexico <a href="https://ecos.fws.gov/ecp0/profile/speciesProfile?spcode=C00U">loggerhead</a> subpopulation. <a href="http://doi.org/10.1016/j.marpolbul.2018.04.001">Microplastic was found at all nesting sites</a>, with the majority of pieces located at the dunes, the primary site where turtles nest. </p>
<p>We took several samples of sand at each nesting site during the Northern Hemisphere summer months, May to August, which is when turtles are nesting in the region.</p>
<p>We are still unsure what the implications of these exposures are, and how much microplastic is needed to change the temperature of the nesting grounds. So, this summer we are expanding our experiments to explore how different densities and types of microplastic can affect the temperature of nesting grounds. </p>
<p>Regardless of the implications, it is important to consider that any alteration to our natural environment may be detrimental to species that rely on then. The good news is that there are several <a href="http://theconversation.com/ten-stealth-microplastics-to-avoid-if-you-want-to-save-the-oceans-90063">easy ways to reduce microplastic</a>.</p>
<p><em>The research was conducted by undergraduate student Valencia Beckwith and Mariana Fuentes.</em></p><img src="https://counter.theconversation.com/content/97164/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mariana Fuentes does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Little chunks of plastic are now scattered throughout the oceans and pollute most beaches around the world, including the nesting sites of threatened and endangered sea turtles.Mariana Fuentes, Assistant Professor in the Department of Earth, Ocean and Atmospheric Science, Florida State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/868262018-02-22T19:10:45Z2018-02-22T19:10:45ZOur acid oceans will dissolve coral reef sands within decades<figure><img src="https://images.theconversation.com/files/207421/original/file-20180222-132650-xoo39k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Researchers studied reef sands at Heron Island, Hawaii, Bermuda and Tetiaroa. In this photo, white areas show the predominance of sand on reefs. </span> <span class="attribution"><span class="source">Southern Cross University</span></span></figcaption></figure><p>Carbonate sands on coral reefs will start dissolving within about 30 years, on average, as oceans become more acidic, <a href="http://science.sciencemag.org/content/359/6378/908">new research</a> published today in Science shows.</p>
<p>Carbonate sands, which accumulate over thousands of years from the breakdown of coral and other reef organisms, are the <a href="https://www.nature.com/articles/nclimate2380">building material</a> for the frameworks of coral reefs and shallow reef environments like lagoons, reef flats and coral sand cays. </p>
<p>But these sands are sensitive to the chemical make-up of sea water. As oceans absorb carbon dioxide, they acidify – and at a certain point, carbonate sands simply start to dissolve. </p>
<p>The world’s oceans have absorbed around one-third of <a href="http://science.sciencemag.org/content/305/5682/362">human-emitted carbon dioxide</a>.</p>
<h2>Carbonate sand is vulnerable</h2>
<p>For a coral reef to grow or be maintained, the rate of carbonate production (plus any external sediment supply) must be greater than the loss through physical, chemical and biological erosion, transport and dissolution.</p>
<p>It is well known that ocean acidification <a href="http://onlinelibrary.wiley.com/doi/10.1111/gcb.12011/full">reduces the amount of carbonate material produced by corals</a>. Our work shows that reefs face a double-whammy: the amount of carbonate material produced will decrease, and the newly produced and stored carbonate sands will also dissolve.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/207430/original/file-20180222-132680-np0pcf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/207430/original/file-20180222-132680-np0pcf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/207430/original/file-20180222-132680-np0pcf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/207430/original/file-20180222-132680-np0pcf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/207430/original/file-20180222-132680-np0pcf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/207430/original/file-20180222-132680-np0pcf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/207430/original/file-20180222-132680-np0pcf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/207430/original/file-20180222-132680-np0pcf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Researchers used benthic chambers (pictured) to test how different levels of seawater acidity affect reef sediments.</span>
<span class="attribution"><span class="source">Steve Dalton/Southern Cross University</span></span>
</figcaption>
</figure>
<p>We measured the impact of acidity on carbonate sands by placing underwater chambers over coral reefs sands at Heron Island, Hawaii, Bermuda and Tetiaroa in the Pacific and Atlantic Oceans. Some of the chambers were then acidified to represent future ocean conditions.</p>
<p>The rate at which the sands dissolve was strongly related to the acidity of the overlying seawater, and was ten times more sensitive than coral growth to ocean acidification. In other words, ocean acidification will impact the dissolution of coral reef sands more than the growth of corals.</p>
<p>This probably reflects the corals’ ability to modify their environment and partially adjust to ocean acidification, whereas the dissolution of sands is a geochemical process that cannot adapt.</p>
<p>Sands on all four reefs showed the same response to future ocean acidification, but the impact of ocean acidification on each reef is different due to different starting conditions. Carbonate sands in Hawaii are already dissolving due to ocean acidification, because this coral reef site is already disturbed by pollution from nutrients and organic matter from the land. The input of nutrients stimulates algal growth on the reef.</p>
<p>In contrast, carbonate sands in Tetiaroa are not dissolving under current ocean acidification because this site is almost pristine.</p>
<h2>What will this mean for coral reefs?</h2>
<p>Our modelling at 22 locations shows that net sand dissolution will vary for each reef. However, by the end of the century all but two reefs across the three ocean basins would on average experience net dissolution of the sands.</p>
<p>A transition to net sand dissolution will result in loss of material for building shallow reef habitats such as reef flats and lagoons and associated coral cays. What we don’t know is whether an entire reef will slowly erode or simply collapse, once the sediments become net dissolving, as the corals will still grow and create reef framework. Although they will most likely just slowly erode.</p>
<p>It may be possible to reduce the impact of ocean acidification on the dissolution of reef sands, by managing the impact of organic matter like algae at local and regional scales. This may provide some hope for some already disturbed reefs, but much more research on this topic is required.</p>
<p>Ultimately, the only way we can stop the oceans acidifying and the dissolving of coral reefs is concerted action to lower CO₂ emissions.</p><img src="https://counter.theconversation.com/content/86826/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bradley Eyre received funding from the Australia Research Council.</span></em></p>Ocean acidification poses an increasing threat to the sediments that form the framework of coral reefs - within around 30 years, these carbonate sands may no longer be able to form.Bradley Eyre, Professor of Biogeochemistry, Director of the Centre for Coastal Biogeochemistry, Southern Cross UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/883932017-12-12T02:39:45Z2017-12-12T02:39:45ZLucky winner: why this beach in WA claims the crown of Australia’s whitest sand<figure><img src="https://images.theconversation.com/files/197087/original/file-20171130-12035-1e1cqvo.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The winner! Lucky Bay, Cape Le Grand National Park, Esperance WA. </span> <span class="attribution"><span class="source">Peter Masters</span></span></figcaption></figure><p>In 2005, when I was chair of the <a href="http://www.soilscienceaustralia.org/ncst">National Committee on Soil and Terrain</a>, I started a debate: where is Australia’s whitest beach? This was a diversion from the committee’s normal business of looking at the sustainable management of Australia’s soils, but it led down a path I hadn’t expected.</p>
<p>What began as a bit of after-hours banter became a serious look across Australia in search of our whitest beaches. New South Wales had already laid claim to the title, arguing that Hyams Beach at Jervis Bay has the <a href="https://open.abc.net.au/explore/28273">whitest sand in the world</a>, purportedly backed up by Guinness World Records. </p>
<p>As it turned out, both claims were false. Guinness World Records has no such category, and the whitest beach (as we found) is actually elsewhere. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/198664/original/file-20171211-9383-1x292qs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/198664/original/file-20171211-9383-1x292qs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/198664/original/file-20171211-9383-1x292qs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/198664/original/file-20171211-9383-1x292qs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/198664/original/file-20171211-9383-1x292qs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/198664/original/file-20171211-9383-1x292qs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/198664/original/file-20171211-9383-1x292qs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/198664/original/file-20171211-9383-1x292qs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Hyams beach in Jervis Bay, NSW, has been rumoured to have the whitest sand in Australia.</span>
<span class="attribution"><span class="source">Kristina Kl./Flickr</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>So we drafted terms of reference, and the search for <a href="http://www.whitestbeach.com">Australia’s Whitest Beach</a> began. Over the next year samples were collected across the nation. The criteria were simple: samples had to be taken from the swash zone (the gently sloping area between the water and the dunes) and the samples could not be treated in any way apart from air-drying. No bleaching. No sieving out of impurities. Marine environment only.</p>
<p>The results of the first judging in 2006 were startling. Of all the states and territories, the much promoted Hyams Beach in New South Wales came in fourth. Third was Victoria, second Queensland, and first Western Australia. </p>
<p>The other states and territories came in at Tasmania fifth, Northern Territory sixth, and South Australia seventh. The ACT didn’t have a beach to sample, although technically some of the Commonwealth lands around our coasts could possibly come in under their banner (but that’s another debate altogether). </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/198662/original/file-20171211-9383-1y7qak8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/198662/original/file-20171211-9383-1y7qak8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/198662/original/file-20171211-9383-1y7qak8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=425&fit=crop&dpr=1 600w, https://images.theconversation.com/files/198662/original/file-20171211-9383-1y7qak8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=425&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/198662/original/file-20171211-9383-1y7qak8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=425&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/198662/original/file-20171211-9383-1y7qak8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=535&fit=crop&dpr=1 754w, https://images.theconversation.com/files/198662/original/file-20171211-9383-1y7qak8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=535&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/198662/original/file-20171211-9383-1y7qak8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=535&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A sample of the main contenders for the whitest beach in Australia. Unfortunately, samples submitted from South Australia didn’t make the final cut.</span>
<span class="attribution"><span class="source">Photo: Noel Schoknecht</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The winning beach was Lucky Bay in Cape Le Grand National Park on WA’s south coast, but in reality any of the beaches in this area could have been winners – Hellfire Bay, Thistle Cove and Wharton’s beach (just to name a few) are all magnificently white.</p>
<p>A quick qualification here: the southwestern end of Lucky Bay, where many people enter the beach, is covered with seaweed – not the whitest bit! I should also note that all of the finalists in the whitest beach challenge were in their own right fabulously white. But when compared side-by-side, some beaches are clearly whiter than others.</p>
<p>The Queensland team felt aggrieved, so in 2007 I carried out a repechage with new samples from Queensland at Whitehaven Beach in the Whitsundays, and Lake McKenzie on Fraser Island. Lake McKenzie was ultimately disallowed as it is a freshwater lake and the rules stipulated a marine environment. Meanwhile, Whitehaven didn’t quite cut the mustard in the judging and Lucky Bay in WA was again the winner.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/198665/original/file-20171211-9416-v5kr92.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/198665/original/file-20171211-9416-v5kr92.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/198665/original/file-20171211-9416-v5kr92.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/198665/original/file-20171211-9416-v5kr92.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/198665/original/file-20171211-9416-v5kr92.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/198665/original/file-20171211-9416-v5kr92.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/198665/original/file-20171211-9416-v5kr92.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/198665/original/file-20171211-9416-v5kr92.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Whitehaven beach in Queensland just missed out on the top spot in the recount.</span>
<span class="attribution"><span class="source">Jared Yeh/Flickr</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<h2>So what makes a beach white, and is it important anyway?</h2>
<p>The assessments were based on a visual comparison, so to remove any possible visual bias after the 2007 challenge all the samples were scanned for their reflectance – how much light bounced off the sand, essentially – in the visible and infrared wavelengths. Our assumption was that higher reflectance throughout the visual spectrum correlates with greater whiteness. </p>
<p>As it turned out, the results from the scanning exactly correlated with the visual assessments. The eye is quite good at discerning small differences in colour and reflectance. (More background and the results from the competition are available <a href="http://www.whitestbeach.com">here</a>.)</p>
<p>So what makes a beach white? Obviously, a pristine environment helps. Another factor is the distance from rivers, which deliver coloured organic and clay contaminants to the coast. </p>
<p>The geology of the area and the source of the sand are also critical, with quartz seemingly a major requirement for fine sands. Most white sandy beaches are derived from granitic, or less commonly sandstone, geologies that weather to produce fine, frosted quartz sand grains. Interestingly, sands made from shell or coral fragments just aren’t as white.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/198671/original/file-20171212-9392-1b85svb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/198671/original/file-20171212-9392-1b85svb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/198671/original/file-20171212-9392-1b85svb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/198671/original/file-20171212-9392-1b85svb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/198671/original/file-20171212-9392-1b85svb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/198671/original/file-20171212-9392-1b85svb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/198671/original/file-20171212-9392-1b85svb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/198671/original/file-20171212-9392-1b85svb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The source of the sand is very important; sand made from shells or coral aren’t as white as quartz.</span>
<span class="attribution"><span class="source">Tracey Croke/Flickr</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Is it important?</h2>
<p>While this competition began in fun, I do believe it’s important. Beaches are places of refuge in this crazy world, and a pristine white beach indicates a cleanliness that is worth striving for. The reflectance of light off these sands through shallow waters near the beach creates a surreal, magical turquoise colour. White beaches are like the canary in the coalmine – once they’re spoiled, we know we’re in trouble.</p>
<p>Even though this study was a first look at some of Australia’s whitest beaches, and sampling was limited, it did highlight the sheer number of wonderful sandy beaches that Australia has. </p>
<p>The story’s not finished though. There are many white beaches out there yet to be sampled, and if you’d like to alert me to your potentially award-winning beach please <a href="whitestbeachinaustralia@gmail.com">email me</a> or leave a comment on the <a href="https://whitestbeach.com/feedback/">whitest beach website</a>.</p>
<p>It’s our responsibility, and I believe honour, to protect these amazing places. I’m sure there are more wonderful beaches out there that we haven’t sampled which may defeat Lucky Bay. </p>
<p>Shelburne Bay in northern Queensland, for example, is a contender yet to be sampled, and there are some magnificent beaches on the east coast of Tasmania. Whatever the outcome, let’s celebrate the natural wonders that surround our country.</p><img src="https://counter.theconversation.com/content/88393/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Noel Schoknecht is affiliated with Soil Science Australia</span></em></p>Lucky Bay on WA’s south coast has been scientifically declared to have the whitest sand in Australia. But if you think your local beach can take the title, we want to hear from you.Noel Schoknecht, Senior research associate, Murdoch UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/835572017-09-07T20:22:02Z2017-09-07T20:22:02ZThe world is facing a global sand crisis<figure><img src="https://images.theconversation.com/files/185180/original/file-20170907-9542-1ye0qul.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sand for use in hydraulic fracturing operations at a processing plant in Chippewa Falls, Wisconsin in 2011.</span> <span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Fracking-Sand-Mining/4e176bf17da14d44af6a83dd00d060b1/23/0">AP Photo/Steve Karnowski)</a>, <span class="license">Author provided</span></span></figcaption></figure><p>When people picture sand spread across idyllic beaches and endless deserts, they understandably think of it as an infinite resource. But as we discuss in a <a href="http://dx.doi.org/10.1126/science.aao0503">just-published perspective</a> in the journal Science, over-exploitation of global supplies of sand is damaging the environment, endangering communities, causing shortages and promoting violent conflict. </p>
<p>Skyrocketing demand, combined with unfettered mining to meet it, is creating the perfect recipe for shortages. Plentiful evidence strongly suggests that sand is becoming increasingly scarce in many regions. For example, in Vietnam domestic demand for sand exceeds the country’s total reserves. If this mismatch continues, the country may run out of construction sand by 2020, according to <a href="http://tuoitrenews.vn/news/society/20170803/vietnam-forecast-to-run-out-of-construction-sand-by-2020/40865.html">recent statements from the country’s Ministry of Construction</a>.</p>
<p>This problem is rarely mentioned in scientific discussions and has not been systemically studied. Media attention drew us to this issue. While scientists are making a great effort to quantify how infrastructure systems such as roads and buildings affect the habitats that surround them, the impacts of extracting construction minerals such as sand and gravel to build those structures have been overlooked. Two years ago we created a working group designed to provide an integrated perspective on global sand use. </p>
<p>In our view, it is essential to understand what happens at the places where sand is mined, where it is used and many impacted points in between in order to craft workable policies. We are analyzing those questions through a <a href="http://dx.doi.org/10.1126/science.1258832">systems integration approach</a> that allows us to better understand socioeconomic and environmental interactions over distances and time. Based on what we have already learned, we believe it is time to develop international conventions to regulate sand mining, use and trade.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/184995/original/file-20170906-9823-1tf131m.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/184995/original/file-20170906-9823-1tf131m.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/184995/original/file-20170906-9823-1tf131m.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/184995/original/file-20170906-9823-1tf131m.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/184995/original/file-20170906-9823-1tf131m.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/184995/original/file-20170906-9823-1tf131m.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/184995/original/file-20170906-9823-1tf131m.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/184995/original/file-20170906-9823-1tf131m.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sand mining on the west side of the Mabukala bridge in Karnataka, India.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:%27sand_mining%27_at_Mabukal.JPG">Rudolph A. Furtado</a></span>
</figcaption>
</figure>
<h2>Skyrocketing demand</h2>
<p>Sand and gravel are now the most-extracted materials in the world, exceeding fossil fuels and biomass (measured by weight). Sand is a key ingredient for <a href="http://matse1.matse.illinois.edu/concrete/bm.html">concrete</a>, roads, <a href="http://www.o-i.com/Why-Glass/How-Glass-Is-Made/">glass</a> and <a href="http://www.popsci.com/diy/article/2005-10/making-silicon-sand">electronics</a>. Massive amounts of sand are mined for <a href="https://www.nytimes.com/2017/04/20/magazine/how-singapore-is-creating-more-land-for-itself.html?mcubz=3&_r=0">land reclamation projects</a>, <a href="http://geology.com/articles/frac-sand/">shale gas extraction</a> and <a href="http://explorebeaches.msi.ucsb.edu/beach-health/beach-nourishment">beach renourishment programs</a>. Recent floods in Houston, India, Nepal and Bangladesh will add to growing global demand for sand.</p>
<p>In 2010, nations mined about 11 billion tonnes of sand <a href="http://www.resourcepanel.org/reports/global-material-flows-and-resource-productivity">just for construction</a>. Extraction rates were highest in the Asia-Pacific region, followed by Europe and North America. In the United States alone, production and use of construction sand and gravel was valued at US$8.9 billion in 2016, and production has <a href="https://minerals.usgs.gov/minerals/pubs/mcs/2017/mcs2017.pdf">increased by 24 percent</a> in the past five years.</p>
<p>Moreover, we have found that these numbers grossly underestimate global sand extraction and use. According to government agencies, uneven record-keeping in many countries <a href="http://onlinelibrary.wiley.com/doi/10.1111/jiec.12471/full">may hide real extraction rates</a>. Official statistics widely underreport sand use and typically do not include nonconstruction purposes such as hydraulic fracturing and beach nourishment. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/185145/original/file-20170907-9549-mopxhj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/185145/original/file-20170907-9549-mopxhj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/185145/original/file-20170907-9549-mopxhj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/185145/original/file-20170907-9549-mopxhj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/185145/original/file-20170907-9549-mopxhj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/185145/original/file-20170907-9549-mopxhj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/185145/original/file-20170907-9549-mopxhj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/185145/original/file-20170907-9549-mopxhj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Dredger pumping sand and water to shore for beach renourishment, Mermaid Beach, Gold Coast, Australia, Aug. 20, 2017.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/XhmVbU">Steve Austin</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Sand traditionally has been a local product. However, regional shortages and sand mining bans in some countries are turning it into a globalized commodity. Its international trade value has skyrocketed, increasing <a href="https://comtrade.un.org/">almost sixfold in the last 25 years</a>.</p>
<p>Profits from sand mining frequently spur profiteering. In response to rampant violence stemming from competition for sand, the government of Hong Kong established a state monopoly over sand mining and trade in the early 1900s <a href="http://www.sciencedirect.com/science/article/pii/S0921800915303979">that lasted until 1981</a>. </p>
<p>Today organized crime groups in India, Italy and elsewhere conduct <a href="https://doi.org/10.1177/1477370816649627">illegal trade in soil and sand</a>. Singapore’s high-volume sand imports have drawn it into disputes with <a href="http://www.nytimes.com/2007/03/16/world/asia/16singapore.html?mcubz=3">Indonesia</a>, <a href="https://www.economist.com/news/asia/21645221-asias-mania-reclaiming-land-sea-spawns-mounting-problems-such-quantities-sand">Malaysia</a> and <a href="http://www.bbc.com/news/business-40590695">Cambodia</a>. </p>
<h2>Sand mining harms humans and the environment</h2>
<p>The negative consequences of overexploiting sand are felt in poorer regions where sand is mined. Extensive sand extraction physically alters rivers and coastal ecosystems, increases suspended sediments and causes erosion.</p>
<iframe frameborder="0" class="juxtapose" width="100%" height="720" src="https://cdn.knightlab.com/libs/juxtapose/latest/embed/index.html?uid=d6b3a49e-93e2-11e7-b263-0edaf8f81e27"></iframe>
<p>Research shows that sand mining operations are affecting numerous animal species, including <a href="http://dx.doi.org/10.1111/sjtg.12150">fish</a>, <a href="https://doi.org/10.1016/j.gecco.2014.09.004">dolphins</a>, <a href="http://dx.doi.org/10.11609/JoTT.o3734.5315-26">crustaceans</a> and <a href="http://dx.doi.org/10.1002/aqc.960">crocodiles</a>. For example, the gharial (<em>Gavialis gangeticus</em>) – a critically endangered crocodile found in Asian river systems – is increasingly threatened by sand mining, which destroys or erodes sand banks where the animals bask.</p>
<p>Sand mining also has serious impacts on people’s livelihoods. Beaches and wetlands buffer coastal communities against surging seas. Increased erosion resulting from extensive mining makes these communities more vulnerable to floods and storm surges. </p>
<p>A recent report by the Water Integrity Network found that sand mining <a href="http://www.waterintegritynetwork.net/2013/10/08/curbing-illegal-sand-mining-in-sri-lanka/">exacerbated the impacts of the 2004 Indian Ocean tsunami in Sri Lanka</a>. In the Mekong Delta, sand mining is reducing sediment supplies as drastically as dam construction, <a href="http://dx.doi.org/10.1038/srep14745">threatening the sustainability of the delta</a>. It also is probably enhancing saltwater intrusion during the dry season, which threatens local communities’ water and food security.</p>
<p>Potential health impacts from sand mining are poorly characterized but deserve further study. Extraction activities create new standing pools of water that can become <a href="https://doi.org/10.1016/S1995-7645(13)60087-5">breeding sites for malaria-carrying mosquitoes</a>. The pools may also play an important role in the spread of emerging diseases such as <a href="https://doi.org/10.1371/journal.pntd.0000911">Buruli ulcer</a> in West Africa, a bacterial skin infection.</p>
<h2>Preventing a tragedy of the sand commons</h2>
<p>Media coverage of this issue is growing, thanks to work by organizations such as the <a href="http://unepineurope.org/index.php?option=com_content&view=article&id=86:unep-global-environmental-alert-service-sand-rarer-than-one-thinks&catid=15&Itemid=101">United Nations Environment Programme</a>, but the scale of the problem is not widely appreciated. Despite huge demand, sand sustainability is rarely addressed in scientific research and policy forums.</p>
<p>The complexity of this problem is doubtlessly a factor. Sand is a common-pool resource – open to all, easy to get and hard to regulate. As a result, we know little about the true global costs of sand mining and consumption.</p>
<p>Demand will increase further as urban areas continue to expand and sea levels rise. Major international agreements such as the <a href="https://sustainabledevelopment.un.org/post2015/transformingourworld">2030 Agenda for Sustainable Development</a> and the <a href="https://www.cbd.int/">Convention on Biological Diversity</a> promote responsible allocation of natural resources, but there are no international conventions to regulate sand extraction, use and trade. </p>
<p>As long as national regulations are lightly enforced, harmful effects will continue to occur. We believe that the international community needs to develop a global strategy for sand governance, along with global and regional sand budgets. It is time to treat sand like a resource, on a par with clean air, biodiversity and other natural endowments that nations seek to manage for the future.</p><img src="https://counter.theconversation.com/content/83557/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Aurora Torres received funding from U.S. National Science Foundation, NASA-MSU Professional Enhancement Awards Program, and US-IALE Foreign Scholar Travel Award Program. </span></em></p><p class="fine-print"><em><span>Jianguo "Jack" Liu receives funding from the National Science Foundation, the NASA-MSU Professional Enhancement Awards Program and Michigan AgBioResearch.</span></em></p><p class="fine-print"><em><span>Kristen Lear received funding from the NASA-MSU Professional Enhancement Awards Program. </span></em></p><p class="fine-print"><em><span>Jodi Brandt does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Overuse of sand for construction and industry is harming the environment and fueling violence around the world. Scientists explain why we need international rules to regulate sand mining and use.Aurora Torres, Postdoctoral Research Fellow in Ecology, German Centre for Integrative Biodiversity ResearchJianguo "Jack" Liu, Rachel Carson Chair in Sustainability, Michigan State UniversityJodi Brandt, Assistant Professor - Human Environment Systems, Boise State UniversityKristen Lear, Ph.D. Candidate, University of GeorgiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/796002017-06-19T10:54:31Z2017-06-19T10:54:31ZHow to build the perfect sandcastle – according to science<figure><img src="https://images.theconversation.com/files/174413/original/file-20170619-12450-ng8uwn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Now you can do it too.</span> <span class="attribution"><span class="source">Matthew Bennett</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Whether we prefer water sports or relaxing with a good book, the humble sandcastle is often a seaside must. But what’s the secret to building a majestic sandcastle that will withstand the tide of time? Luckily, there’s a scientific formula for that.</p>
<p>It all started back in 2004, when a holiday company asked us to <a href="https://research.bournemouth.ac.uk/engagement/the-perfect-sandcastle/">investigate the question</a>. As a sedimentologist, someone who studies fragments of rock, I began pondering what kind of beach would work best for castle building. To find out, I compared the sand from the ten most popular beaches in the UK at the time. Though in truth any sandy beach will do, <a href="https://en.wikipedia.org/wiki/Torquay">Torquay</a> came out top with its delightful red sand, closely followed by <a href="https://en.wikipedia.org/wiki/Bridlington">Bridlington</a>, with <a href="https://en.wikipedia.org/wiki/Bournemouth">Bournemouth</a>, <a href="https://en.wikipedia.org/wiki/Great_Yarmouth">Great Yarmouth</a> and <a href="https://en.wikipedia.org/wiki/Tenby">Tenby</a> tied in third. At the bottom of the league was <a href="https://en.wikipedia.org/wiki/Rhyl">Rhyl</a>. </p>
<p>Having selected a beach one has to find the perfect spot. Now this is a question of taste rather than hard rules. Some might prefer a spot close to the car park with easy access when the rain arrives while others might want to stay next to a cafe. Others yet might hanker after the secluded fringes of the beach, perhaps sheltered by natural promontories of rock that keep the biting wind at bay.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/174429/original/file-20170619-12397-1ve13tf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/174429/original/file-20170619-12397-1ve13tf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/174429/original/file-20170619-12397-1ve13tf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/174429/original/file-20170619-12397-1ve13tf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/174429/original/file-20170619-12397-1ve13tf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/174429/original/file-20170619-12397-1ve13tf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/174429/original/file-20170619-12397-1ve13tf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Torquay harbour.</span>
<span class="attribution"><span class="source">averoxus/wikipedia</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Now a castle should be a symbol of military strength, but to stand proud one needs strong sand. The strength of sand depends on the properties of its individual grains and on the water between them. The more angular the grains, the better they will lock together. The more a grain is transported the more rounded it becomes. Microscopic shell fragments work well in this regard. The finer the grains the more they hold the water. And water matters. </p>
<p>Too much water and your sand will flow, too little and it will crumble. You need to get it just right and your castle will stand proud and last. It’s all down to the surface tension of water – the thing that gives the “meniscus”, or skin, to a glass of water and holds down that glass when placed on a wet bar top. The film of water between individual sand grains is what gives sand its strength, too much and it lubricates one grain over the other, but just right and it binds them strong.</p>
<h2>The magic formula</h2>
<p>Now the experimentation we did suggested that the perfect sandcastle requires one bucket of water to eight buckets of dry sand. Or if you want the magic formula: Water = 0.125 x Sand. So assuming that you don’t have any science gear with you, then you are looking for a spot close to the high tide line – usually marked by a line of seaweed and flotsam – and the low tide line where sand is still visibly wet and the waves are close. But remember that this will change as the tide comes and goes during the day.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/174431/original/file-20170619-27202-7n7u80.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/174431/original/file-20170619-27202-7n7u80.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/174431/original/file-20170619-27202-7n7u80.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/174431/original/file-20170619-27202-7n7u80.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/174431/original/file-20170619-27202-7n7u80.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/174431/original/file-20170619-27202-7n7u80.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/174431/original/file-20170619-27202-7n7u80.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">High tide line.</span>
</figcaption>
</figure>
<p>My next tip refers to quality of your tools. In my experience there is a direct correlation between the age of the builder, spade size and the speed at which boredom sets in. Adult helpers find the smallest spade nothing but frustrating, and while young assistants might aspire to use the biggest spade, it is often too big to handle. A selection of tools will keep the workforce in harmony. The bucket also has to be the perfect size and shape. The best buckets are the simple round ones – not the ones with the fancy turrets which when turned out produce a castle in itself. A round bucket will allow you turn out countless towers and architectural features. A single bucket can be turned out several times to create a large mound from which you carve an amazing tower. </p>
<p>As you build, spare a thought to the story, not just of the castle one is building with its tales of derring-do, but also the story of the sand itself. Each grain is a fragment of rock and contains a story of relict mountains, ancient rivers, <a href="https://theconversation.com/the-top-six-dinosaur-myths-and-how-we-busted-them-59031?sr=1">dinosaur-infested swamps and seas</a>, of <a href="https://theconversation.com/geologists-unveil-how-britain-first-separated-from-europe-and-it-was-catastrophic-75636?sr=13">past climates and events</a> which tell the amazing story of our planet. The red sand of Torquay once blew in giant sandstorms, as the area was once <a href="https://www.bgs.ac.uk/mendips/AncientEnv/triassic.html">part of a desert</a> far greater than that of the Sahara. The sand at Bridlington or Great Yarmouth tells a tale of <a href="http://www.dailymail.co.uk/sciencetech/article-2167731/Britains-Atlantis-North-sea--huge-undersea-kingdom-swamped-tsunami-5-500-years-ago.html">giant ice sheets and drowned lands</a> below the North Sea.</p>
<p>My next tip refers to size. Yes, size matters – at least in the game of sandcastles. The modest castle with perfect towers, battlements and moat is ok, but it is the huge castles which break the beach horizon that inspire awe and wonderment in people that pass by. Think big! Pebbles, shells, driftwood fragments and feathers all enhance a castle. And let’s face it: a castle is about being seen. And although there may be science behind the humble sandcastle, don’t forget to have fun building it.</p><img src="https://counter.theconversation.com/content/79600/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matthew Robert Bennett does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>There is a direct correlation between the age of the builder, spade size and the speed at which boredom sets in.Matthew Robert Bennett, Professor of Environmental and Geographical Sciences, Bournemouth UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/641522016-12-09T02:07:57Z2016-12-09T02:07:57ZCatching lightning in a fossil – and calculating how much energy a strike contains<figure><img src="https://images.theconversation.com/files/149316/original/image-20161208-31402-vgl94l.jpg?ixlib=rb-1.1.0&rect=229%2C9%2C1634%2C1299&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Very powerful, try to avoid.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/rickywilson/2569675373">Rick Wilson</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>For most of human history, people have been terrified by lightning. <a href="http://www.sacred-texts.com/afr/fssn/fsn21.htm">Frightening bolts from above</a>, lightning was a <a href="http://lightningsafety.com/nlsi_info/myths.html">tool of the gods</a> to smite mortals for their hubris (or their unfortunate penchant for seeking shelter from storms under trees). The discovery and implementation of <a href="https://www.fi.edu/history-resources/franklins-lightning-rod">Benjamin Franklin’s lightning rod</a> tamed this once formidable, divine weapon.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/149318/original/image-20161208-31352-1m75vph.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149318/original/image-20161208-31352-1m75vph.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/149318/original/image-20161208-31352-1m75vph.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=897&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149318/original/image-20161208-31352-1m75vph.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=897&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149318/original/image-20161208-31352-1m75vph.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=897&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149318/original/image-20161208-31352-1m75vph.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1127&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149318/original/image-20161208-31352-1m75vph.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1127&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149318/original/image-20161208-31352-1m75vph.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1127&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Will a lightning bolt contain enough energy to blast Marty McFly through time?</span>
</figcaption>
</figure>
<p>Nonetheless, lightning’s strength still lingers in our imagination. Hollywood considers it powerful enough to allow strangely designed cars from the early 1980s to <a href="http://www.imdb.com/title/tt0088763/">break the space-time continuum</a>. In the comic book world, it’s an ingredient in the <a href="https://en.wikipedia.org/wiki/Flash_(Barry_Allen)">formula for developing superpowers</a>. It has also been given the power to <a href="https://en.wikipedia.org/wiki/Frankenstein%27s_monster">return life to the dead</a>, though not always with the intended effect.</p>
<p>Just how much energy actually is in a lightning bolt? It may seem like this question should have been definitively answered before, but it turns out it’s difficult to answer quantitatively. In my research, we <a href="http://doi.org/10.1038/srep30586">tackled this issue in a new way</a>: We deduced how big a bolt of lightning was based on the size of rocks formed by lightning.</p>
<h2>Rough estimates</h2>
<p>Lightning is obviously powerful: One need only look at a tree that it’s splintered down the center for proof. Lightning generates temperatures hotter than the surface of the sun, <a href="http://doi.org/10.1016/0021-9169(64)90113-8">in excess of 20,000 degrees Celsius</a>, a temperature that is otherwise unrelateable to the human experience.</p>
<p>This temperature measurement provides <a href="http://doi.org/10.1029/RG022i004p00363">one way to estimate the energy of lightning</a>. It takes a certain amount of energy to heat air to a high temperature. By measuring the length of a lightning strike, multiplying it by the energy per length required to heat up the air to tens of thousands of degrees, we can calculate lightning’s energy.</p>
<p>Alternatively, we can approach the measurement of lightning energy by considering the voltage of a strike. A volt is a measurement of the amount of energy released as each pack of electrons flows from one side of an object to another – for instance, a battery. When lightning strikes, we can determine the <a href="http://doi.org/10.1109/15.249398">voltage it induces on nearby powerlines</a>; measurements range from hundreds of thousands to millions of volts. From <a href="https://en.wikipedia.org/wiki/Ohm%27s_law">Ohm’s law</a>, we can calculate the power of lightning by multiplying this by the number of electrons that move during the strike, a value known as the current. If we know the duration of this strike, we can then calculate the energy.</p>
<p>These methods have a large range of errors: not calculating the length of the lightning strike correctly, or getting the amount of gas heated per length wrong, or the temperature, or voltage, or number of electrons – all give pretty large errors for these calculations. </p>
<p>Could there be another route to calculating lightning energy that might pare down some of these errors? Florida’s unique geology provided an interesting route to answering this question.</p>
<h2>Fossilized lightning</h2>
<p>Florida tends to be a fairly boring state for a rock enthusiast. There’s sand, and there’s limestone. Not much else, and all of it is young, geologically speaking. Sometimes the sand is on top of the limestone, and sometimes it’s on the side. Sometimes the sand was deposited 15 million years ago, sometimes 5 million years ago. There’s a lot of sand. </p>
<p>Florida’s weather is a bit more interesting; it’s actually the U.S. state <a href="http://www.vaisala.com/VaisalaImages/Lightning/avg_sd_2005-2014_CONUS_2km_grid.png">most often struck by lightning</a>. A lot of times this lightning strikes the sand that covers the state. When it does so, it creates a new type of rock, called a fulgurite – a hollow tube formed as the lightning travels through the sand, vaporizing it and melting its outer edges. When the sand cools down, which happens quickly, the hollow tube is frozen in glass, recording the path the lightning traveled. By definition, a fulgurite is a metamorphic rock, changed by heat and pressure, from sand to something new.</p>
<p>Fulgurites are generally rare, unless you know where to look. Central peninsular Florida hosts several sand mines that supply the raw material for roads and cement, golf courses and playgrounds. At one site, we collected several hundred fulgurites; more than 250 lay in the field, with many more found in spoil piles, filtered out of the sand prior to its being loaded onto trucks.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/149290/original/image-20161208-31383-kx7vxr.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149290/original/image-20161208-31383-kx7vxr.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/149290/original/image-20161208-31383-kx7vxr.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149290/original/image-20161208-31383-kx7vxr.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149290/original/image-20161208-31383-kx7vxr.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149290/original/image-20161208-31383-kx7vxr.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149290/original/image-20161208-31383-kx7vxr.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149290/original/image-20161208-31383-kx7vxr.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The sand mine in Polk County, Florida, from which the fulgurites were collected.</span>
<span class="attribution"><span class="source">Matthew Pasek</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>These sites are not really any different than any place else in Florida – they aren’t some sort of lightning magnet – but the geologic setting was just right for keeping them around for a long time. These sand mines probably have about one million year’s worth of fulgurites buried inside of them. They’re easy to find – since glass isn’t something you want in commercial sand, the mine filters them out.</p>
<p>The fulgurites range in thickness from about the size of a baby’s little finger to about the size of man’s arm in thickness. The thicker ones had to be formed by much more energetic lightning bolts: a thicker fulgurite means more sand had to be vaporized. Most fulgurites we recovered were short fragments, though the longest ones found were a yard or two long.</p>
<h2>Calculating from the fulgurites</h2>
<p>It takes a specific amount of energy to vaporize sand into gas. First the sand has to be heated to around 1700°C, about the temperature of molten lava. At this temperature, the sand melts. The molten sand then has to heat to just shy of 3000°C, when it vaporizes. It takes about 15 megajoules of energy to heat and vaporize a kilogram of sand. That’s about the amount of energy the average U.S. household consumes in six hours, or the kinetic energy an average car would have if it were going 300 miles per hour.</p>
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<a href="https://images.theconversation.com/files/149300/original/image-20161208-31385-xczm6h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149300/original/image-20161208-31385-xczm6h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/149300/original/image-20161208-31385-xczm6h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149300/original/image-20161208-31385-xczm6h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149300/original/image-20161208-31385-xczm6h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149300/original/image-20161208-31385-xczm6h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149300/original/image-20161208-31385-xczm6h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149300/original/image-20161208-31385-xczm6h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The largest fulgurite found during recovery at the sand mine.</span>
<span class="attribution"><span class="source">Matt Pasek</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>After measuring our fulgurites, we determined that on average, the energy required to form these rocks was at least about one megajoule per meter of fulgurite formed. We calculated the energy per meter since, again in most cases, the fulgurites we had collected were broken. </p>
<p>So based on our calculations, how close does Hollywood come, with estimates like in “Back to the Future” of 1.21 gigawatts of power in lightning? Power is energy per time, and our measurements of fulgurites suggest that megajoules of energy make rock in thousandths to millionths of seconds. So a gigawatt is actually on the low side – lightning power may be a thousand times that, reaching into the terawatts, though the average is probably tens of gigawatts.</p>
<p>That’s enough energy to power about a billion houses, albeit only for a few millionths of a second. Unfortunately, given its sporadic and unpredictable nature, no power grid will ever be able to harness lightning effectively. But with that much power, perhaps breaking the space-time continuum in a souped-up Delorean is not so unfeasible after all….</p>
<h2>An oddity in the pattern</h2>
<p>When we looked at these fulgurites in depth, something odd came out of the data. Our energy measurements followed something called a “lognormal” trend.</p>
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<p>Rather than following the bell curve we often see in the distribution of natural phenomena – like, for instance, the heights of American men – the energy curve was less equally balanced. For heights, the same number of men are two inches above average as are two inches below. But for lightning, the large lightning strikes were much larger than the average, while the smaller strikes were not so much smaller than the average. Strikes that were twice the average were as frequent as those that were half the average.</p>
<p>Now why might this be at all interesting or useful? Measuring the energy in lightning is a way of measuring potential damage: A lightning strike can vaporize rock, so what might it do to wood or electronics? Our measurements show that the biggest lightning strikes are multiples of the average lightning strikes: A big one might be 20 times as large as the average. That’s a lot for a <a href="https://en.wikipedia.org/wiki/Lightning_rod#Lightning_protection_system">lightning protection system</a> to handle. The peak energy calculated from our rock-based method may give an idea as to the maximum damage we may expect, and may eventually allow for better preparation against the worst-case scenario.</p><img src="https://counter.theconversation.com/content/64152/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matthew Pasek receives funding from NASA Exobiology and Evolutionary Biology (Grant NNX14AN96G)</span></em></p>Lightning strikes are powerful – but we haven’t had solid estimates of their energy until now. Researchers turned to the hollow stone tubes they create by vaporizing sand for more precise calculations.Matthew Pasek, Associate Professor of Geosciences, University of South FloridaLicensed as Creative Commons – attribution, no derivatives.