tag:theconversation.com,2011:/africa/topics/seasons-24605/articlesSeasons – The Conversation2024-03-22T12:34:47Ztag:theconversation.com,2011:article/2221082024-03-22T12:34:47Z2024-03-22T12:34:47ZClimate change is shifting the zones where plants grow – here’s what that could mean for your garden<figure><img src="https://images.theconversation.com/files/583569/original/file-20240321-20-wkg9tp.jpg?ixlib=rb-1.1.0&rect=6%2C0%2C4019%2C2474&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Climate change complicates plant choices and care. Early flowering and late freezes can kill flowers like these magnolia blossoms.</span> <span class="attribution"><span class="source">Matt Kasson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>With the <a href="https://www.pbs.org/newshour/science/the-vernal-equinox-marks-the-first-day-of-spring-what-does-that-mean">arrival of spring</a> in North America, many people are gravitating to the gardening and landscaping section of home improvement stores, where displays are overstocked with eye-catching seed packs and benches are filled with potted annuals and perennials. </p>
<p>But some plants that once thrived in your yard may not flourish there now. To understand why, look to the U.S. Department of Agriculture’s recent update of its <a href="https://planthardiness.ars.usda.gov/">plant hardiness zone map</a>, which has long helped gardeners and growers figure out which plants are most likely to thrive in a given location. </p>
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<a href="https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A U.S. map divided into colored geographic zones with a numbered key." src="https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?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 2023 USDA plant hardiness zone map shows the areas where plants can be expected to grow, based on extreme winter temperatures. Darker shades (purple to blue) denote colder zones, phasing southward into temperate (green) and warm zones (yellow and orange).</span>
<span class="attribution"><a class="source" href="https://planthardiness.ars.usda.gov/">USDA</a></span>
</figcaption>
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<p>Comparing the 2023 map to the previous version from 2012 clearly shows that as climate change warms the Earth, plant hardiness zones are shifting northward. On average, the coldest days of winter in our current climate, based on temperature records from 1991 through 2020, are 5 degrees Fahrenheit (2.8 Celsius) warmer than they were between 1976 and 2005. </p>
<p>In some areas, including the central Appalachians, northern New England and north central Idaho, winter temperatures have warmed by 1.5 hardiness zones – 15 degrees F (8.3 C) – over the same 30-year window. This warming changes the zones in which plants, whether annual or perennial, will ultimately succeed in a climate on the move.</p>
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<a href="https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="U.S. map showing large areas colored tan, denoting a 5-degree increase in average winter minimum temperatures." src="https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=464&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=464&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=464&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=583&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=583&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=583&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This map shows how plant hardiness zones have shifted northward from the 2012 to the 2023 USDA maps. A half-zone change corresponds to a tan area. Areas in white indicate zones that experienced minimal change.</span>
<span class="attribution"><a class="source" href="https://site.extension.uga.edu/climate/2023/11/new-usda-plant-hardiness-zone-map-shows-most-of-southeast-has-gotten-one-half-zone-warmer/">Prism Climate Group, Oregon State University</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>As a <a href="https://scholar.google.com/citations?user=frEPl6IAAAAJ&hl=en">plant pathologist</a>, I have devoted my career to understanding and addressing plant health issues. Many stresses not only shorten the lives of plants, but also affect their growth and productivity. </p>
<p>I am also a gardener who has seen firsthand how warming temperatures, pests and disease affect my annual harvest. By understanding climate change impacts on plant communities, you can help your garden reach its full potential in a warming world.</p>
<h2>Hotter summers, warmer winters</h2>
<p>There’s no question that the temperature trend is upward. From 2014 through 2023, the world experienced the <a href="https://www.noaa.gov/news/world-just-sweltered-through-its-hottest-august-on-record">10 hottest summers ever recorded</a> in 174 years of climate data. Just a few months of sweltering, unrelenting heat can significantly affect plant health, especially <a href="https://extension.psu.edu/cool-season-vs-warm-season-vegetables">cool-season garden crops</a> like broccoli, carrots, radishes and kale. </p>
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<a href="https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Radishes sprouting in a garden bed." src="https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=302&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=302&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=302&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=380&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=380&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=380&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Radishes are cool-season garden crops that cannot withstand the hottest days of summer.</span>
<span class="attribution"><span class="source">Matt Kasson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>Winters are also warming, and this matters for plants. The USDA defines plant hardiness zones based on the coldest average annual temperature in winter at a given location. Each zone represents a 10-degree F range, with zones numbered from 1 (coldest) to 13 (warmest). Zones are divided into 5-degree F half zones, which are lettered “a” (northern) or “b” (southern). </p>
<p>For example, the coldest hardiness zone in the lower 48 states on <a href="https://planthardiness.ars.usda.gov/">the new map</a>, 3a, covers small pockets in the northernmost parts of Minnesota and has winter extreme temperatures of -40 F to -35 F. The warmest zone, 11b, is in Key West, Florida, where the coldest annual lows range from 45 F to 50 F. </p>
<p>On the <a href="https://planthardiness.ars.usda.gov/system/files/US_Map_2012.jpg">2012 map</a>, northern Minnesota had a much more extensive and continuous zone 3a. North Dakota also had areas designated in this same zone, but those regions now have shifted completely into Canada. Zone 10b once covered the southern tip of mainland Florida, including Miami and Fort Lauderdale, but has now been pushed northward by a rapidly encroaching zone 11a. </p>
<p>Many people buy seeds or seedlings without thinking about hardiness zones, planting dates or disease risks. But when plants have to contend with temperature shifts, heat stress and disease, they will eventually struggle to survive in areas where they once thrived. </p>
<p>Successful gardening is still possible, though. Here are some things to consider before you plant:</p>
<h2>Annuals versus perennials</h2>
<p>Hardiness zones matter far less for <a href="https://www.britannica.com/science/annual">annual plants</a>, which germinate, flower and die in a single growing season, than for <a href="https://www.britannica.com/science/perennial">perennial plants</a> that last for several years. Annuals typically avoid the lethal winter temperatures that define plant hardiness zones. </p>
<p>In fact, most annual seed packs don’t even list the plants’ hardiness zones. Instead, they provide sowing date guidelines by geographic region. It’s still important to follow those dates, which help ensure that frost-tender crops are not planted too early and that cool-season crops are not harvested too late in the year.</p>
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<a href="https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Orange flowers blooming with other plants and grasses." src="https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.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">California poppies are typically grown as annuals in cool areas, but can survive for several years in hardiness zones 8-10.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/FWtHc">The Marmot/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<h2>User-friendly perennials have broad hardiness zones</h2>
<p>Many perennials can grow across wide temperature ranges. For example, hardy fig and hardy kiwifruit grow well in zones 4-8, an area that includes most of the Northeast, Midwest and Plains states. Raspberries are hardy in zones 3-9, and blackberries are hardy in zones 5-9. This eliminates a lot of guesswork for most gardeners, since a majority of U.S. states are dominated by two or more of these zones. </p>
<p>Nevertheless, it’s important to pay attention to plant tags to avoid selecting a variety or cultivar with a restricted hardiness zone over another with greater flexibility. Also, pay attention to instructions about proper sun exposure and planting dates after the last frost in your area. </p>
<h2>Fruit trees are sensitive to temperature fluctuations</h2>
<p>Fruit trees have two parts, the rootstock and the scion wood, that are <a href="https://extension.unh.edu/sites/default/files/migrated_unmanaged_files/Resource003733_Rep5323.pdf">grafted together to form a single tree</a>. Rootstocks, which consist mainly of a root system, determine the tree’s size, timing of flowering and tolerance of soil-dwelling pests and pathogens. Scion wood, which supports the flowers and fruit, determines the fruit variety. </p>
<p>Most commercially available fruit trees can tolerate a wide range of hardiness zones. However, stone fruits like peaches, plums and cherries are more sensitive to temperature fluctuations within those zones – particularly abrupt swings in winter temperatures that create unpredictable freeze-thaw events. </p>
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<a href="https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Packages for hardy fig and kiwi seedlings." src="https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=467&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=467&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=467&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=587&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=587&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=587&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Following planting instructions carefully can maximize plants’ chances of success.</span>
<span class="attribution"><span class="source">Matt Kasson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>These seesaw weather episodes affect all types of fruit trees, but stone fruits appear to be more susceptible, possibly because they flower earlier in spring, have fewer hardy rootstock options, or have bark characteristics that make them more vulnerable to winter injury. </p>
<p>Perennial plants’ hardiness increases through the seasons in a process called <a href="https://extension.umd.edu/resource/hardening-vegetable-seedlings-home-garden/">hardening off</a>, which conditions them for harsher temperatures, moisture loss in sun and wind, and full sun exposure. But a too-sudden autumn temperature drop can cause plants to die back in winter, an event known as <a href="https://extension.psu.edu/winterkill-of-turfgrasses">winter kill</a>. Similarly, a sudden spring temperature spike can lead to premature flowering and subsequent frost kill.</p>
<h2>Pests are moving north too</h2>
<p>Plants aren’t the only organisms constrained by temperature. With milder winters, southern insect pests and plant pathogens are expanding their ranges northward. </p>
<p>One example is <a href="https://www.britannica.com/science/blight">Southern blight</a>, a stem and root rot disease that affects 500 plant species and is caused by a fungus, <em>Agroathelia rolfsii</em>. It’s often thought of as affecting hot Southern gardens, but has become more commonplace recently in the Northeast U.S. on tomatoes, <a href="https://theconversation.com/how-to-keep-your-jack-o-lantern-from-turning-into-moldy-maggoty-mush-before-halloween-190526">pumpkins and squash</a>, and other crops, including <a href="https://extension.psu.edu/apple-disease-southern-blight">apples in Pennsylvania</a>. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A stem dotted with small round growths." src="https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.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">Southern blight (small round fungal structures) at the base of a tomato plant.</span>
<span class="attribution"><a class="source" href="https://ag.purdue.edu/department/arge/swpap/southern-blight-tomato.html">Purdue University</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Other plant pathogens may take advantage of milder winter temperatures, which leads to prolonged saturation of soils instead of freezing. Both plants and microbes are less active when soil is frozen, but in wet soil, microbes have an opportunity to colonize dormant perennial plant roots, leading to more disease.</p>
<p>It can be challenging to accept that climate change is stressing some of your garden favorites, but there are thousands of varieties of plants to suit both your interests and your hardiness zone. Growing plants is an opportunity to <a href="https://theconversation.com/take-a-break-from-your-screen-and-look-at-plants-botanizing-is-a-great-way-to-engage-with-life-around-you-210616">admire their flexibility</a> and the features that enable many of them to thrive in a world of change.</p><img src="https://counter.theconversation.com/content/222108/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matt Kasson receives funding from the US Department of Agriculture.</span></em></p>The US Department of Agriculture has updated its plant hardiness zone map, which shows where various plants will grow across the country. Gardeners should take note.Matt Kasson, Associate Professor of Mycology and Plant Pathology, West Virginia UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2256972024-03-15T13:32:00Z2024-03-15T13:32:00ZHaiku has captured the essence of seasons for centuries – new poems contain a trace of climate change<p>A successful haiku could be described as a half-finished poem. Originating in Japan <a href="https://www.britannica.com/art/haiku">in the 17th century</a>, the haiku uses a combination of sensory language, seasonal references, a sense of contrast and a focus on the present tense to share an experience between writer and reader. </p>
<p>It relies on the reader to “finish” the poem by employing their recollections of sensations and emotions to connect to the moment described as vividly as they do their own experiences.</p>
<p>Haiku often depict moments in a particular season by describing the behaviour of animals, the weather and the appearance of plants. With a new generation of haiku poets, there’s a whole new collection of work that reflects how seasons are changing as a result of rising global temperatures.</p>
<p>Could haiku poetry written more recently contain a trace of the changes wrought by our warming climate? That’s something one of us (Jasmin) set out to investigate by analysing haiku published in English over the last 30 years. </p>
<p>First, let’s learn how to read haiku.</p>
<hr>
<p><em>Do the seasons feel increasingly weird to you? You’re not alone. Climate change is distorting nature’s calendar, causing plants to flower early and animals to emerge at the wrong time.</em></p>
<p><em>This article is part of a series, <a href="https://theconversation.com/uk/topics/wild-seasons-152175?utm_source=InArticleTop&utm_medium=TCUK&utm_campaign=WS">Wild Seasons</a>, on how the seasons are changing – and what they may eventually look like.</em></p>
<hr>
<p>What enables this brief poetic form to achieve its resonance is its use of negative space. A haiku is a poem in two parts – a fragment (one line) and a phrase (two lines), divided by a pause (signified by a line break or punctuation). </p>
<p>Related to the concept of <a href="https://new.uniquejapan.com/ikebana/ma/"><em>ma</em></a> in Japanese visual arts, which perceives empty space in an artwork as a positive entity, the negative space in haiku is a way in to the contemplative experience of the poem.</p>
<p>The following by Japanese poet <a href="https://en.wikipedia.org/wiki/Matsuo_Bash%C5%8D">Matsuo Basho</a> (1644-94) is the most famous haiku ever composed:</p>
<blockquote>
<p>old pond –</p>
<p>a frog leaps in</p>
<p>water’s sound</p>
</blockquote>
<figure class="align-center ">
<img alt="A frog in a pond surrounded by spawn." src="https://images.theconversation.com/files/581926/original/file-20240314-28-a0jjk9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/581926/original/file-20240314-28-a0jjk9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581926/original/file-20240314-28-a0jjk9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581926/original/file-20240314-28-a0jjk9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581926/original/file-20240314-28-a0jjk9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581926/original/file-20240314-28-a0jjk9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581926/original/file-20240314-28-a0jjk9.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">Frogspawn is a harbinger of spring in the UK.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/common-frog-frogspawn-uk-1328083865">Lesley Andrew/Shutterstock</a></span>
</figcaption>
</figure>
<p>To write a different account of this same event, you could say something like a frog leapt into an old pond and made a sound. But the key distinction between the two is the negative space that follows Basho’s first line. It encourages the reader to pause, breathe and contemplate the old pond before they encounter the frog leaping and the sound of the water. </p>
<p>When our minds become still, and reflective, like the old pond, we witness the action of an animal living simply according to its nature. We perceive things just as they are. The result is an experience of interconnectedness: a realisation that we are not separate from the natural world, but a part of it.</p>
<p>In the following haiku by Basho we experience the season as both a physical setting and as a metaphor for emotional experience:</p>
<blockquote>
<p>no-one walks</p>
<p>along this road but I</p>
<p>autumn evening</p>
</blockquote>
<figure class="align-center ">
<img alt="A tree-lined urban path in the evening." src="https://images.theconversation.com/files/581927/original/file-20240314-30-dpj1lj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/581927/original/file-20240314-30-dpj1lj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581927/original/file-20240314-30-dpj1lj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581927/original/file-20240314-30-dpj1lj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581927/original/file-20240314-30-dpj1lj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581927/original/file-20240314-30-dpj1lj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581927/original/file-20240314-30-dpj1lj.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">Autumn’s arrival can be felt in falling leaves and earlier sunsets.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/autumn-city-night-maple-trees-alley-1950393067">S_Oleg/Shutterstock</a></span>
</figcaption>
</figure>
<p>In a world of increasing anxiety and distraction, the negative space in a haiku affords us moments of reflection and invites us into a dialogue with the rest of the natural world. </p>
<p>It requires a sensitivity on the part of the reader, but its effect is to instil an appreciation for what surrounds us. Through a meaningful, felt awareness of the seasonal cycles, the reading and writing of haiku inspires a deeper connection to our environment.</p>
<h2>How haiku is changing</h2>
<p>I spent the summer of 2022 in my home office, consuming decades of haiku journals and anthologies, trying not to leave sweaty fingerprints on their ancient covers in the unnatural 40°C heat. As that year’s researcher-in-residence for the British Haiku Society, working on a project called <a href="http://britishhaikusociety.org.uk/wp-content/uploads/2016/10/Twisting-Point.pdf">Twisting Point</a>, I was searching for tell-tale traces of climate change in the English-language haiku archives.</p>
<p>My goal was to contrast present-day haiku against older archival ones, using the differences between them to make readers sensitive to nature’s decline and to suggest how the English-language haiku form might be evolving due to climate change. </p>
<p>I was looking at 30 years’ worth of haiku. In the UK during this time flying insect populations have <a href="https://www.nhm.ac.uk/discover/news/2022/may/uks-flying-insects-have-declined-60-in-20-years.html">fallen by over 60%</a>, 41% of wildlife species have <a href="https://www.theguardian.com/environment/2019/oct/03/populations-of-uks-most-important-wildlife-have-plummeted-since-1970#:%7E:text=In%2520addition%2520to%2520the%2520214,%252C%2520habitat%2520loss%2520and%2520degradation.">decreased in abundance</a> and the frequency of heatwaves, floods and other extreme weather have <a href="https://www.metoffice.gov.uk/about-us/press-office/news/weather-and-climate/2022/uk-climate-continues-to-change-in-2021#:%7E:text=The%2520latest%2520annual%2520report%2520shows,the%2520year%2520across%2520the%2520UK.">all increased</a>. More than enough change has occurred in these three decades to manifest in the archives.</p>
<p>Yet, these changes emerge in a strange fashion. It’s hard to write about nature’s losses, and writers tend to do so unconsciously. Rather than tracking population declines in concrete terms, then, the language used around certain species has altered, becoming soaked in grief.</p>
<p>For example, over 25 years numbers of curlews, a wading bird, have <a href="https://www.bto.org/our-science/projects/breeding-bird-survey/bbs-publications/bbs-reports">halved</a> in the UK. Earlier haiku described their powerful cry “lengthen[ing] the hill[s]”; a poem written in 2022 found them “calling across wintry mudflats, haunting the wind”. Similarly, since 2000, <a href="https://butterfly-conservation.org/sites/default/files/2023-01/State%20of%20UK%20Butterflies%202022%20Report.pdf">declining butterflies</a> have moved from being a “cloud” common in the background of haiku to lone survivors “pushing against time”.</p>
<figure class="align-center ">
<img alt="A wading bird in shallow water with a long, slender, curved beak." src="https://images.theconversation.com/files/582070/original/file-20240314-26-b83fcc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/582070/original/file-20240314-26-b83fcc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/582070/original/file-20240314-26-b83fcc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/582070/original/file-20240314-26-b83fcc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/582070/original/file-20240314-26-b83fcc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/582070/original/file-20240314-26-b83fcc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/582070/original/file-20240314-26-b83fcc.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">Curlews use their crescent beaks to probe the soft intertidal mud for worms.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/curlew-blue-nature-background-bird-eurasian-393557542">Emutan/Shutterstock</a></span>
</figcaption>
</figure>
<p>The archetypal seasonal words used in haiku are shifting too, disrupting centuries-long traditions of meaning and emotion. As winter has been squeezed into weeks, spring arrives earlier and frosts become tardier, snowdrops have become a symptom of the changing haiku form.</p>
<p>Here is a haiku published in the 1990s in the spring seasonal category (the traditional haiku date for spring’s beginning is February 4):</p>
<blockquote>
<p>song of a greenfinch</p>
<p>a ray of sun on cold steps </p>
<p>and a few snowdrops</p>
</blockquote>
<p>By 2022, snowdrops are emerging in December in this tanka (a slightly longer poem variety) by Ruth Parker:</p>
<blockquote>
<p>Omicron triumphs</p>
<p>and sends Christmas packing – but in the garden</p>
<p>the delicate white hope</p>
<p>of snowdrops</p>
</blockquote>
<figure class="align-center ">
<img alt="Small white flowers." src="https://images.theconversation.com/files/581929/original/file-20240314-24-rorauy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/581929/original/file-20240314-24-rorauy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581929/original/file-20240314-24-rorauy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581929/original/file-20240314-24-rorauy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581929/original/file-20240314-24-rorauy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581929/original/file-20240314-24-rorauy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581929/original/file-20240314-24-rorauy.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">Snowdrops are flowering earlier as the climate warms.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/snowdrop-common-galanthus-nivalis-flowers-1319256830">Daniel Chetroni/Shutterstock</a></span>
</figcaption>
</figure>
<p>I was struck by how few haiku seemed to address climate change. Twisting Point became my call to arms for haiku writers. Haiku are about intense moments of perception, in which <a href="http://britishhaikusociety.org.uk/wp-content/uploads/2016/10/Twisting-Point.pdf">“the vast is perceived in one thing”</a>. But in addressing climate change so little, are English-language haiku really depicting “the vast”?</p>
<p>Since 2022 the issue has come to the fore, with The Guardian describing how Japanese haiku writers are <a href="https://www.theguardian.com/environment/2023/nov/14/lost-to-the-climate-crisis-japan-haiku-poets">“lost for words”</a> in the face of climate change. Meanwhile, Twisting Point is to be <a href="https://poetrysociety.org.nz/affiliates/haiku-nz/haiku-poems-articles/">republished in a journal</a> of the New Zealand Poetry Society. The call to haiku arms is growing: the vast climate crisis is upon us, and we should write about it.</p><img src="https://counter.theconversation.com/content/225697/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jasmin Kirkbride is a member of the British Haiku Society, the Association for the Study of Literature and the Environment (ASLE-UKI) and the Haiku Foundation Registry. She is also a member of the Society of Authors and Mensa.</span></em></p><p class="fine-print"><em><span>Paul Chambers 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>Haiku poems chart flowers appearing earlier and species retreating to the margins.Jasmin Kirkbride, Lecturer in Publishing, University of East AngliaPaul Chambers, PhD Candidate in Creative Writing, University of BristolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2218932024-03-06T17:45:12Z2024-03-06T17:45:12ZClimate change is warping the seasons<figure><img src="https://images.theconversation.com/files/580225/original/file-20240306-26-bvdh70.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5666%2C3766&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/snowdrop-wild-flowers-base-tree-february-2262926611">Shawnwil23/Shutterstock</a></span></figcaption></figure><p>The seasons aren’t what they used to be. </p>
<p>People who live in Earth’s middle latitudes are accustomed to a spring, summer, autumn and winter. If you’re in the northern hemisphere, you may have noticed plants flowering earlier than usual. It’s not your imagination: a 2022 study revealed that spring blooms are <strong><a href="https://theconversation.com/plants-are-flowering-a-month-earlier-heres-what-it-could-mean-for-pollinating-insects-176324">arriving a month sooner</a></strong> in the UK due to climate change.</p>
<p>For <strong><a href="https://theconversation.com/introducing-wild-seasons-a-new-series-on-how-a-warming-world-is-warping-natures-calendar-224811">a new series</a></strong> on the seasons and how they’re being warped by a warming climate, over the coming months we’ll be examining the consequences of these wrinkles in nature’s calendar.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.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">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em><strong>This roundup of The Conversation’s climate coverage comes from our <a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeTop">weekly climate action newsletter</a>.</strong> Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. <a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeBottom">Join the 30,000+ readers who’ve subscribed.</a></em></p>
<hr>
<h2>How plants sense the seasons</h2>
<p>Other species can’t coordinate their activities around a date and time. Plants, the bedrock of most ecosystems, stay up to date by paying close attention to changes in light and temperature says Paul Ashton, head of biology at Edge Hill University.</p>
<p>Plants are among the first to know when the days start to contract in autumn, as they use a pigment called phytochrome to detect changes in red light.</p>
<p>“While this subtle shift escapes humans (our eyes are not sensitive to this part of the spectrum) a plant can detect this transition and start to change.”</p>
<figure class="align-center ">
<img alt="Sun shining through the gap in a tree at dusk." src="https://images.theconversation.com/files/580227/original/file-20240306-20-8u8mly.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/580227/original/file-20240306-20-8u8mly.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/580227/original/file-20240306-20-8u8mly.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/580227/original/file-20240306-20-8u8mly.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/580227/original/file-20240306-20-8u8mly.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/580227/original/file-20240306-20-8u8mly.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/580227/original/file-20240306-20-8u8mly.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">Trees sense the onset of autumn by detecting subtle changes in red light.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/warm-autumnal-evening-mountains-lovely-atmospheric-2192857717">Brum/Shutterstock</a></span>
</figcaption>
</figure>
<p>“Just as the autumn can engineer a drop in the level of the hormone serotonin in our blood, a plant that has sensed winter’s approach will increase the production of a hormone called abscisic acid,” Ashton says. Abscisic acid makes deciduous trees shed their leaves and grow tough winter buds that are resistant to frost.</p>
<p>Temperature tells many plants <a href="https://theconversation.com/plants-are-flowering-earlier-than-ever-heres-how-they-sense-the-seasons-223930">when to start growing</a> in the spring. Ashton says it isn’t clear how plants sense this, but again, pigments in their cells probably play a role.</p>
<p>“[Plants] sense the days getting warmer and alter their spring development in a manner akin to humans feeling warmth on their skin and so stepping out with fewer layers of clothing,” he says.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/plants-are-flowering-earlier-than-ever-heres-how-they-sense-the-seasons-223930">Plants are flowering earlier than ever – here’s how they sense the seasons</a>
</strong>
</em>
</p>
<hr>
<p>That’s where climate change has complicated things: rising air temperatures have yielded shorter, milder winters. Since 1986, plants in the UK now greet spring 26 days earlier, on average.</p>
<p>This relatively rapid shift has severed an arrangement plants and animals have negotiated over thousands of years.</p>
<p>“Insects that are used to feasting on April-flowering plants may find themselves arriving a month late if warmer temperatures mean that the plants now flower in March,” say Chris Wyver and Laura Reeves, PhD candidates who study pollination and climate change at the University of Reading.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/plants-are-flowering-a-month-earlier-heres-what-it-could-mean-for-pollinating-insects-176324">Plants are flowering a month earlier – here's what it could mean for pollinating insects</a>
</strong>
</em>
</p>
<hr>
<h2>Out of the loop</h2>
<p>Hungry bugs are bad enough. But if insects are emerging too late to visit expectant flowers then it’s <a href="https://theconversation.com/climate-breakdown-is-knocking-the-natural-world-out-of-sync-and-we-should-all-be-worried-123892">the entire ecosystem that suffers</a>.</p>
<p>“Take, for example, the birds of European oak woods, such as the blue tit, great tit and pied flycatcher,” says Charlie Gardner, a lecturer in conservation biology at the University of Kent. Caterpillars are emerging earlier than they did in the past, and the birds that eat them can’t keep up.</p>
<p>“For every ten-day advance in caterpillar emergence, the birds are only able to bring forward their egg laying by three to five days, depending on the species,” he says.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/climate-breakdown-is-knocking-the-natural-world-out-of-sync-and-we-should-all-be-worried-123892">Climate breakdown is knocking the natural world out of sync – and we should all be worried</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="A bird with a beak full of insect prey." src="https://images.theconversation.com/files/580228/original/file-20240306-18-wxjrwp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/580228/original/file-20240306-18-wxjrwp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/580228/original/file-20240306-18-wxjrwp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/580228/original/file-20240306-18-wxjrwp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/580228/original/file-20240306-18-wxjrwp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/580228/original/file-20240306-18-wxjrwp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/580228/original/file-20240306-18-wxjrwp.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">Birds can only adapt so much to seasonal shifts in the emergence of their prey.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/crested-lark-galerida-cristata-breeding-season-2319794185">Rudmer Zwerver/Shutterstock</a></span>
</figcaption>
</figure>
<p>Freak weather, a more common feature of our heating climate, can also confuse the finely calibrated senses of wildlife and trick some species into thinking the season shifted while they weren’t paying attention. </p>
<p>Stuart Thompson, a senior lecturer in plant biochemistry at the University of Westminster, highlights how the drought that parched Europe in 2022 convinced some trees to lose their leaves – giving the impression of <a href="https://theconversation.com/drought-why-some-uk-trees-are-losing-their-leaves-in-august-188576">autumn in mid-August</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/drought-why-some-uk-trees-are-losing-their-leaves-in-august-188576">Drought: why some UK trees are losing their leaves in August</a>
</strong>
</em>
</p>
<hr>
<p>Across the broader trends that scientists have documented at least one thing is consistent: winter is being squeezed from both sides as the world heats up. </p>
<p>“Climate researchers now have nearly five decades of satellite observations at their disposal,” says Jadu Dash, a professor of remote sensing at the University of Southampton.</p>
<p>“Analysis of this data reveals that spring has advanced by approximately 15 days, while <a href="https://theconversation.com/how-climate-change-is-affecting-the-seasons-213590">autumn has been delayed</a> by a similar amount.”</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-climate-change-is-affecting-the-seasons-213590">How climate change is affecting the seasons</a>
</strong>
</em>
</p>
<hr>
<p>But climate change won’t simply usher in seasons where everything happens either a month earlier or later. Some species will delay hibernation and emerge in spring sooner, but others will stick to their original schedule, taking their cues from day length rather than temperature. </p>
<p>The result will be chaos, says Gardner:</p>
<p>“If we are to have any chance of preserving the living planet and avoiding the extinction of a million species, then we need to do more than stop climate breakdown. We need to invest in conservation too, to help wild plants and animals adapt to the changes we’ve already locked in. Not doing so would be bad news for all of us.”</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.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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<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
<br><em><a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeTop">Get a weekly roundup in your inbox instead.</a> Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. <a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeBottom">Join the 30,000+ readers who’ve subscribed so far.</a></em></p>
<hr><img src="https://counter.theconversation.com/content/221893/count.gif" alt="The Conversation" width="1" height="1" />
A new series will investigate what’s happening to nature’s calendar.Jack Marley, Environment + Energy Editor, UK editionLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2239302024-02-29T17:37:28Z2024-02-29T17:37:28ZPlants are flowering earlier than ever – here’s how they sense the seasons<p>Hedgerows in mid-February might have traditionally appeared white with snow; this year the white was the work of blackthorn blossoms – a harbinger of spring. Although a welcome sign after a wet and gloomy winter, the early flowering brings unease for experienced season watchers. Has this plant always flowered in mid-February, I wondered, or is something changing?</p>
<p>Fortunately, the science of recording and understanding seasonal events, phenology, has a long history in Britain. <a href="https://www.robertmarsham.co.uk/">Robert Marsham</a>, an 18th-century naturalist, kept records of the appearance of the flowers, birds and insects in his Norfolk village as far back as 1736. Marsham’s descendants continued the recording until 1958. The Woodland Trust maintains the tradition with <a href="https://naturescalendar.woodlandtrust.org.uk/">Nature’s Calendar</a>, a scheme in which members of the public are invited to record various seasonal events.</p>
<p><a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2021.2456">Detailed analysis</a> of almost half a million plant records by scientists in 2022 showed that when all species were considered together the average flowering time in the UK had advanced by a month over the last 40 years. There was variation between species. Hawthorn, the common hedgerow plant, is generally flowering 13 days earlier than it did in the early 1980s while the flowers of the horse chestnut tree appear ten days earlier.</p>
<p>The climate has warmed rapidly since the 1980s. By flowering earlier, plants recognise that winters are becoming shorter and milder. They sense the days getting warmer and alter their spring development in a manner akin to humans feeling warmth on their skin and so stepping out with fewer layers of clothing. The precise mechanisms for detecting these cues differ between plants and animals, but both are responding to the climate as it changes. </p>
<h2>Detecting light and heat without eyes and skin</h2>
<p>Plants detect the shortening days of autumn with a pigment called phytochrome that is particularly sensitive to wavelengths in the red region of the electromagnetic spectrum. The longer autumn nights alter the quality of this red light. While this subtle shift escapes humans (our eyes are not sensitive to this part of the spectrum) a plant can detect this transition and start to change.</p>
<figure class="align-center ">
<img alt="A bench next to a woodland at sunset." src="https://images.theconversation.com/files/578640/original/file-20240228-18-qoad8t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/578640/original/file-20240228-18-qoad8t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/578640/original/file-20240228-18-qoad8t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/578640/original/file-20240228-18-qoad8t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/578640/original/file-20240228-18-qoad8t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/578640/original/file-20240228-18-qoad8t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/578640/original/file-20240228-18-qoad8t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Plants detect subtle changes in red light and instigate dormancy as autumn descends.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/romantic-autumn-mood-sunset-lake-ammersee-690569119">Art180/Shutterstock</a></span>
</figcaption>
</figure>
<p>Just as the autumn can engineer a drop in the level of the hormone serotonin in our blood, a plant that has sensed winter’s approach will increase the production of a hormone called abscisic acid. This has multiple effects. In deciduous trees, twigs stop growing and develop tough winter buds capable of surviving frost and snow and leaves fall off.</p>
<p>Growth in spring is determined by similar triggers of light length and temperature, but temperature typically has the more significant role. If plants only paid attention to light, they’d run the risk of starting growth when fatal frosts are still a threat or of missing good growing time in mild early spring days. Temperature detection determines when spring flowers appear. This is why global heating is evident in the earlier appearance of these flowers.</p>
<hr>
<p><em>Do the seasons feel increasingly weird to you? You’re not alone. Climate change is distorting nature’s calendar, causing plants to flower early and animals to emerge at the wrong time.</em></p>
<p><em>This article is part of a series, <a href="https://theconversation.com/uk/topics/wild-seasons-152175?utm_source=InArticleTop&utm_medium=TCUK&utm_campaign=WS">Wild Seasons</a>, on how the seasons are changing – and what they may eventually look like.</em></p>
<hr>
<p>It isn’t fully understood how plants detect temperature. Some of it may be due to a growth-stalling hormone in its cells breaking down when the air falls below a certain temperature, which in turn allows a growth hormone to increase. </p>
<p>While humans have nerves in their skin to detect temperature, plants probably rely on pigments, though the mechanism isn’t fully understood. Heat is part of the same electromagnetic spectrum that phytochrome is sensitive to, so possibly this pigment is involved. Whatever mechanisms are responsible for initiating growth, temperature also determines how fast plants grow.</p>
<h2>Flowers and pollinators out of sync</h2>
<p>Insect pollinators like bees must synchronise their life cycles so that they are on the wing when the blossoms on which they feed emerge. The timing of their emergence from winter is also determined by the effects of temperature and day length and mediated by hormones. </p>
<p>Evolution working on many generations of pollinators has generated a tight link between the emergence of flowers and that of their pollinators. If the appearance of flowers and pollinators isn’t synchronised, the insects have no nectar and the plants aren’t fertilised. </p>
<p>A similar link exists between the emergence of leaves and the insect herbivores that graze on them. The rapidity of climate change and slight differences in how the two groups respond risk breaking this synchrony with serious consequences for both sides.</p>
<p><a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2021.2142">A large study</a> by German scientists looking at when flowers and their pollinators emerged between 1980 and 2020 found a complex picture. Both responded to climate change with earlier flowering and appearances, but the plants had made a greater shift. </p>
<p>There was variation between insect groups, bees and butterflies had shifted in synchrony with the plants, but this wasn’t observed in hoverflies. There was also variation between species of these insects.</p>
<figure class="align-center ">
<img alt="A white butterfly on a purple flower." src="https://images.theconversation.com/files/578642/original/file-20240228-30-erxph1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/578642/original/file-20240228-30-erxph1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=409&fit=crop&dpr=1 600w, https://images.theconversation.com/files/578642/original/file-20240228-30-erxph1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=409&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/578642/original/file-20240228-30-erxph1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=409&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/578642/original/file-20240228-30-erxph1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=513&fit=crop&dpr=1 754w, https://images.theconversation.com/files/578642/original/file-20240228-30-erxph1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=513&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/578642/original/file-20240228-30-erxph1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=513&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Plants and insects co-evolved to emerge at roughly the same time in Spring.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/blackveined-white-butterfly-aporia-crataegi-perfect-79443766">Marek Mierzejewski/Shutterstock</a></span>
</figcaption>
</figure>
<p>Even when plants and their dependent insects change timings in synchrony, the next stage of the food chain may not be so flexible. Oak leaves are fed upon by the oak moth caterpillar. This, in turn, is the primary food of the chicks of birds such as blue tits and pied flycatchers <a href="https://www.nature.com/articles/s41559-018-0543-1">link text</a>. Chicks have hatched at roughly the same time, while oak leaves and caterpillars have appeared earlier and so far remain in synchrony. But for how long?</p>
<p>Blackthorn blossoms remain a welcome relief from winter and a sign that spring is on its way. But they are also a sign of climate change: an unfolding experiment on the timing and synchrony of plants and animals – and the intricate food chains that they are part of.</p><img src="https://counter.theconversation.com/content/223930/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul Ashton 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>Rising air temperatures mean shorter winters and earlier springs.Paul Ashton, Professor of Botany, Edge Hill UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2183302024-02-19T13:36:56Z2024-02-19T13:36:56ZWhy does a leap year have 366 days?<figure><img src="https://images.theconversation.com/files/575717/original/file-20240214-24-h6q6if.jpg?ixlib=rb-1.1.0&rect=38%2C23%2C5137%2C3422&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Leap Day is coming.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/calendar-on-february-29-on-a-leap-year-leap-day-royalty-free-image/1196849410">Marvin Samuel Tolentino Pineda/iStock, via Getty images</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>Why does a leap year have 366 days? Does the Earth move slower every four years? – Aarush, age 8, Milpitas, California</p>
</blockquote>
<hr>
<p>You may be used to hearing that it takes the Earth 365 days to make a full lap, but that journey actually lasts about 365 and a quarter days. Leap years help to keep the 12-month calendar matched up with Earth’s movement around the Sun. </p>
<p>After four years, those leftover hours add up to a whole day. In a leap year, we add this extra day to the month of February, making it 29 days long instead of the usual 28.</p>
<p>The idea of an annual catch-up dates back to ancient Rome, where people had a calendar with 355 days instead of 365 because it was based on cycles and phases of the Moon. They noticed that their calendar was getting out of sync with the seasons, so they began adding an extra month, <a href="https://www.britannica.com/science/Roman-republican-calendar">which they called Mercedonius</a>, every two years to catch up with the missing days.</p>
<p>In the year 45 B.C.E., Roman emperor Julius Caesar introduced a solar calendar, based on one developed in Egypt. Every four years, February received an extra day to keep the calendar in line with the Earth’s journey around the Sun. In honor of Caesar, this system is still known as the Julian calendar.</p>
<p>But that wasn’t the last tweak. As time went on, people realized that the Earth’s journey wasn’t exactly 365.25 days – it <a href="https://airandspace.si.edu/stories/editorial/science-leap-year">actually took 365.24219 days</a>, which is about 11 minutes less. So adding a whole day every four years was actually a little more correction than was needed. </p>
<p>In 1582, Pope Gregory XIII signed an order that made a small adjustment. There would still be a leap year every four years, except in “century” years – years divisible by 100, like 1700 or 2100 – unless they were also divisible by 400. It might sound a bit like a puzzle, but this adjustment made the calendar <a href="https://airandspace.si.edu/stories/editorial/science-leap-year">even more accurate</a> – and from that point on, it was known as the Gregorian calendar.</p>
<h2>What if we didn’t have leap years?</h2>
<p>If the calendar didn’t make that small correction every four years, it would gradually fall out of alignment with the seasons. Over centuries, this could lead to the <a href="https://www.britannica.com/story/whats-the-difference-between-a-solstice-and-an-equinox">solstices and equinoxes</a> occurring at different times than expected. Winter weather might develop in what the calendar showed as summer, and farmers could become confused about when to plant their seeds.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/YTOr8_ILqGw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Without leap years, our calendar would gradually become disconnected from the seasons.</span></figcaption>
</figure>
<p>Other calendars around the world have their own ways of keeping time. The Jewish calendar, which is regulated by <a href="https://www.britannica.com/topic/Jewish-religious-year">both the Moon and the Sun</a>, is like a big puzzle with a 19-year cycle. Every now and then, it adds a leap month to make sure that special celebrations happen at just the right time. </p>
<p>The <a href="https://ing.org/resources/for-all-groups/calendar-of-important-islamic-dates/">Islamic calendar</a> is even more unusual. It follows the <a href="https://spaceplace.nasa.gov/moon-phases/en/">phases of the Moon</a> and doesn’t add extra days. Since a lunar year is only about 355 days long, key dates on the Islamic calendar move 10 to 11 days earlier each year on the solar calendar. </p>
<p>For example, Ramadan, the <a href="https://ing.org/resources/for-all-groups/calendar-of-important-islamic-dates/">Islamic month of fasting</a>, falls in the ninth month of the Islamic calendar. In 2024, it will run from March 11 to April 9; in 2025, it will occur from March 1-29; and in 2026, it will be celebrated from Feb. 18 to March 19.</p>
<h2>Learning from the planets</h2>
<p>Astronomy originated as a way to make sense of our daily lives, linking the events around us to celestial phenomena. The concept of leap years exemplifies how, from early ages, humans found order in conditions that seemed chaotic. </p>
<p>Simple, unsophisticated but effective tools, born from creative ideas of ancient astronomers and visionaries, provided the first glimpses into understanding the nature that envelops us. Some <a href="https://www.britannica.com/science/astronomy/History-of-astronomy">ancient methods</a>, such as <a href="https://sci.esa.int/web/gaia/-/53196-the-oldest-sky-maps">astrometry and lists of astronomical objects</a>, persist even today, revealing the timeless essence of our quest to understand nature. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/575719/original/file-20240214-30-of8z7y.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photograph of an intricate schematic guide to the night sky." src="https://images.theconversation.com/files/575719/original/file-20240214-30-of8z7y.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/575719/original/file-20240214-30-of8z7y.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=356&fit=crop&dpr=1 600w, https://images.theconversation.com/files/575719/original/file-20240214-30-of8z7y.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=356&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/575719/original/file-20240214-30-of8z7y.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=356&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/575719/original/file-20240214-30-of8z7y.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=447&fit=crop&dpr=1 754w, https://images.theconversation.com/files/575719/original/file-20240214-30-of8z7y.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=447&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/575719/original/file-20240214-30-of8z7y.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=447&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Ancient Egyptians were dedicated astronomers. This section from the ceiling of the tomb of Senenmut, a high court official in Egypt, was drawn sometime circa 1479–1458 B.C.E. It shows constellations, protective gods and 24 segmented wheels for the hours of the day and the months of the year.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Senenmut-Grab.JPG">NebMaatRa/Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>People who do research in physics and astronomy, the <a href="https://scholar.google.com/citations?user=t4L_D18AAAAJ&hl=en">field that I study</a>, are inherently curious about the workings of the universe and our origins. This work is exciting, and also extremely humbling; it constantly shows that in the grand scheme, our lives occupy a mere second in the vast expanse of space and time – even in leap years when we add that extra day.</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/218330/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bhagya Subrayan 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>Humans have synced their calendars to the sun and moon for centuries, but every so often, these systems need a little correction.Bhagya Subrayan, PhD Student in Physics and Astronomy, Purdue UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2168742024-01-10T13:28:57Z2024-01-10T13:28:57ZEarth isn’t the only planet with seasons, but they can look wildly different on other worlds<figure><img src="https://images.theconversation.com/files/561980/original/file-20231127-27-h9xkjy.jpg?ixlib=rb-1.1.0&rect=0%2C6%2C2055%2C1445&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Nearby planets can affect how one planet 'wobbles' on its spin axis, which contributes to seasons. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/orbits-of-planets-in-the-solar-system-royalty-free-illustration/1148112202?phrase=planets+orbit&adppopup=true">Mark Garlick/Science Photo Library via Getty Images</a></span></figcaption></figure><p>Spring, summer, fall and winter – the seasons on Earth change every few months, around the same time every year. It’s easy to take this cycle for granted here on Earth, but not every planet has a regular change in seasons. So why does Earth have regular seasons when other planets don’t? </p>
<p><a href="https://scholar.google.com/citations?user=vxyrNXoAAAAJ&hl=en">I’m an astrophysicist</a> who studies the movement of planets and the causes of seasons. Throughout my research, I’ve found that Earth’s regular pattern of seasons is unique. The <a href="https://theconversation.com/how-the-earths-tilt-creates-short-cold-january-days-173403">rotational axis that Earth spins on</a>, along the North and South poles, <a href="https://en.wikipedia.org/wiki/Axial_tilt">isn’t quite aligned</a> with the vertical axis perpendicular to Earth’s orbit around the Sun. </p>
<p>That slight tilt has big implications for everything from seasons to glacier cycles. The magnitude of that tilt can even determine whether a planet is habitable to life. </p>
<h2>Seasons on Earth</h2>
<p>When a planet has perfect alignment between the axis it orbits on and the rotational axis, the amount of sunlight it receives is fixed as it orbits around the Sun – assuming its orbital shape is a circle. Since seasons come from variations in how much sunlight reaches the planet’s surface, a planet that’s perfectly aligned wouldn’t have seasons. But Earth isn’t perfectly aligned on its axis.</p>
<p>This small misalignment, called an obliquity, is <a href="https://en.wikipedia.org/wiki/Axial_tilt">around 23 degrees</a> from vertical for Earth. So, the Northern Hemisphere experiences more intense sunlight during the summer, when the Sun is positioned more directly above the Northern Hemisphere.</p>
<p>Then, as the Earth continues to orbit around the Sun, the amount of sunlight the Northern Hemisphere receives gradually decreases as the Northern Hemisphere tilts away from the Sun. This causes winter. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/566402/original/file-20231218-21-biar6k.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A diagram showing the Earth as a blue circle on the left and on the right, with a blue arrow tilted a few degrees towards the right cutting through it, and a green arrow tilted up cutting through it. The angle between the two arrows is red, labeled 'obliquity.' In the middle is a drawing of the Sun." src="https://images.theconversation.com/files/566402/original/file-20231218-21-biar6k.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566402/original/file-20231218-21-biar6k.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566402/original/file-20231218-21-biar6k.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566402/original/file-20231218-21-biar6k.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566402/original/file-20231218-21-biar6k.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566402/original/file-20231218-21-biar6k.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566402/original/file-20231218-21-biar6k.png?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">The obliquity marks the difference between the Earth’s spin axis (blue) and the vertical from orbit (green). The Northern Hemisphere experiences summer when the tilt lines it up directly with light from the Sun.</span>
<span class="attribution"><span class="source">Gongjie Li</span></span>
</figcaption>
</figure>
<p>The planets spinning on their axes and orbiting around the Sun look kind of like spinning tops – they spin around and wobble because of gravitational pull from the Sun. As a top spins, you might notice that it doesn’t just stay perfectly upright and stationary. Instead, it may start to tilt or wobble slightly. This tilt is what astrophysicists call <a href="https://www.britannica.com/science/precession-of-the-equinoxes">spin precession</a>.</p>
<p>Because of these wobbles, Earth’s obliquity isn’t perfectly fixed. These small variations in tilt can have <a href="https://www.jstor.org/stable/1746691">big effects on the Earth’s climate</a> when combined with small changes to Earth’s orbit shape. </p>
<p>The wobbling tilt and any natural variations to the shape of Earth’s orbit can change the amount and distribution of sunlight reaching Earth. These small changes contribute to the planet’s larger temperature shifts over thousands to hundreds of thousands of years. This can, in turn, <a href="https://climate.nasa.gov/news/2948/milankovitch-orbital-cycles-and-their-role-in-earths-climate/">drive ice ages and periods of warmth</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/DD_8Jm5pTLk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Earth’s seasons result from a variety of factors, including orbit and axial tilt.</span></figcaption>
</figure>
<h2>Translating obliquity into seasons</h2>
<p>So how do obliquity variations affect the seasons on a planet? Low obliquity, meaning the rotational spin axis is aligned with the planet’s orientation as it orbits around the Sun, <a href="https://climate.nasa.gov/news/2948/milankovitch-orbital-cycles-and-their-role-in-earths-climate/">leads to</a> stronger sunlight on the equator and low sunlight near the pole, like on Earth. </p>
<p>On the other hand, a high obliquity – meaning the planet’s rotational spin axis points toward or away from the Sun – <a href="https://climate.nasa.gov/news/2948/milankovitch-orbital-cycles-and-their-role-in-earths-climate/">leads to</a> extremely hot or cold poles. At the same time, the equator gets cold, as the Sun does not shine above the equator all year round. This leads to drastically varying seasons at high latitudes and low temperatures at the equator. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/566405/original/file-20231218-19-pudn6j.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A planet with a reversed zonation is represented by a blue circle next to a drawing of a sun, with a green oval representing the planet's orbit around the sun. A blue arrow pointing towards the sun represents the planet's spin axis, and a green arrow point up represents the planet's orbit direction." src="https://images.theconversation.com/files/566405/original/file-20231218-19-pudn6j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566405/original/file-20231218-19-pudn6j.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566405/original/file-20231218-19-pudn6j.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566405/original/file-20231218-19-pudn6j.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566405/original/file-20231218-19-pudn6j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566405/original/file-20231218-19-pudn6j.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566405/original/file-20231218-19-pudn6j.png?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">When a planet’s spin axis is tilted far from the vertical axis, it has a high obliquity. That means the equator barely gets any sunlight and the North Pole faces right at the Sun.</span>
<span class="attribution"><span class="source">Gongjie Li</span></span>
</figcaption>
</figure>
<p>When a planet has an obliquity of more than 54 degrees, that planet’s equator grows icy and <a href="https://doi.org/10.1016/0012-8252(93)90004-Q">the pole becomes warm</a>. This is called <a href="https://doi.org/10.1016/0012-8252(93)90004-Q">a reversed zonation</a>, and it’s the opposite of what Earth has. </p>
<p>Basically, if an obliquity has large and unpredictable variations, the seasonal variations on the planet become wild and hard to predict. A dramatic, large obliquity variation can turn the whole planet into a snowball, <a href="https://doi.org/10.1093/mnras/stab3179">where it’s all covered by ice</a>. </p>
<h2>Spin orbit resonances</h2>
<p>Most planets are not the only planets in their solar systems. Their planetary siblings can disturb each other’s orbit, which can lead to variations in the shape of their orbits and their orbital tilt. </p>
<p>So, planets in orbit look kind of like tops spinning on the roof of a car that’s bumping down the road, where the car represents the orbital plane. When the rate – or frequency, as scientists call it – at which the tops are precessing, or spinning, matches the frequency at which the car is bumping up and down, something called a <a href="https://doi.org/10.1038/361615a0">spin-orbit resonance</a> occurs.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/561691/original/file-20231126-23-xe830c.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A diagram showing a planet, shown as a blue circle with an arrow through it representing a tilted, spinning axis, orbiting around the Sun, with another planet's orbit overlapping with it, causing the orbit to tilt up and down." src="https://images.theconversation.com/files/561691/original/file-20231126-23-xe830c.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/561691/original/file-20231126-23-xe830c.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/561691/original/file-20231126-23-xe830c.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/561691/original/file-20231126-23-xe830c.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/561691/original/file-20231126-23-xe830c.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/561691/original/file-20231126-23-xe830c.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/561691/original/file-20231126-23-xe830c.png?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">The orbits of planets close by and the precession motion of a planet on its axis can affect seasonal patterns.</span>
<span class="attribution"><span class="source">Gongjie Li</span></span>
</figcaption>
</figure>
<p>Spin-orbit resonances can cause these obliquity variations, which is when a planet wobbles on its axis. Think about pushing a kid on a swing. When you push at just the right time – or at the resonant frequency – they’ll swing higher and higher.</p>
<p>Mars wobbles more on its axis than Earth does, even though the two are tilted about the same amount, and that actually has to do with the Moon orbiting around Earth. Earth and Mars have a <a href="https://doi.org/10.1038/361608a0">similar spin precession frequency</a>, which matches the orbital oscillation – the ingredients for a spin-orbit resonance. </p>
<p>But Earth has a massive Moon, which pulls on Earth’s spin axis and drives it to precess faster. This slightly faster precession prevents it from experiencing spin orbit resonances. So, the Moon stabilizes Earth’s obliquity, and Earth doesn’t wobble on its axis as much as Mars does. </p>
<h2>Exoplanet seasons</h2>
<p><a href="https://theconversation.com/are-there-any-planets-outside-of-our-solar-system-164062">Thousands of exoplanets</a>, or planets outside our solar system, have been discovered over the past few decades. My research group wanted to understand how habitable these planets are, and whether these exoplanets also have wild obliquities, or whether they have moons to stabilize them like Earth does. </p>
<p>To investigate this, my group has led the first investigation on <a href="https://doi.org/10.3847/1538-3881/aabfd1">the spin-axis variations of exoplanets</a>. </p>
<p>We investigated <a href="https://doi.org/10.3847/1538-3881/aabfd1">Kepler-186f</a>, which is the first discovered Earth-sized planet in a habitable zone. <a href="https://theconversation.com/an-earth-sized-planet-found-in-the-habitable-zone-of-a-nearby-star-129290">The habitable zone</a> is an area around a star where liquid water can exist on the surface of the planet and life may be able to emerge and thrive.</p>
<p>Unlike Earth, Kepler-186f is located far from the other planets in its solar system. As a result, these other planets have only a weak effect on its orbit and movement. So, Kepler-186f generally <a href="https://doi.org/10.3847/1538-3881/aabfd1">has a fixed obliquity</a>, similar to Earth. Even without a large moon, it doesn’t have wildly changing or unpredictable seasons like Mars.</p>
<p>Looking forward, more research into exoplanets will help scientists understand what seasons look like throughout the vast diversity of planets in the universe.</p><img src="https://counter.theconversation.com/content/216874/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gongjie Li receives funding from NASA.</span></em></p>You might hate winter, but at least you know what to expect every year. Other planets have wobbly axes that lead to wild, unpredictable seasons.Gongjie Li, Assistant Professor of Physics, Georgia Institute of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2169312023-11-14T13:02:09Z2023-11-14T13:02:09ZThis is the world’s hottest autumn on record – and it’s impacting the climate system and human society<p>We are still getting used to a “new normal” of devastating summer heatwaves. But the effects of a warming climate are being felt throughout the year, and recent autumn months have been further off the charts than ever.</p>
<p>In fact, climate change and an <a href="https://theconversation.com/four-possible-consequences-of-el-nino-returning-in-2023-198105">El Niño</a> have both contributed to the world in 2023 having its <a href="https://www.theguardian.com/environment/2023/oct/01/autumn-heat-continues-in-europe-after-record-breaking-september">hottest autumn</a> since records began in 1850. <a href="https://climate.copernicus.eu/copernicus-september-2023-unprecedented-temperature-anomalies">September</a> was 0.93°C above the 1991-2020 average, and a whole <a href="https://theconversation.com/heres-whats-driving-the-record-autumn-heat-its-not-just-carbon-emissions-215097">1.75°C</a> above the 1850-1900 pre-industrial reference period. October was also the hottest on record, at <a href="https://climate.copernicus.eu/copernicus-october-2023-exceptional-temperature-anomalies-2023-virtually-certain-be-warmest-year#:%7E:text=October%202023%20was%20the%20warmest,previous%20warmest%20October%2C%20in%202019.">0.85°C</a> above the recent average.</p>
<p>This hot autumn has already meant stronger storms and more intense rainfall and droughts. And this in turn affects farming, energy, tourism and other sectors that depend on reliable seasons. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1709911218641666550"}"></div></p>
<h2>A global system but local effects</h2>
<p>Warmer oceans have been linked to <a href="https://www.nature.com/articles/s41467-022-29379-1">intensification of storms</a> in the Atlantic. One of these, <a href="https://theconversation.com/storm-babet-caused-dangerous-floods-as-the-dry-side-of-scotland-isnt-used-to-such-torrential-rain-216103">Storm Babet</a>, recently broke UK rainfall records <a href="https://www.metoffice.gov.uk/binaries/content/assets/metofficegovuk/pdf/weather/learn-about/uk-past-events/interesting/2023/2023_08_storm_babet.pdf">dating back to 1881</a>. Babet was soon followed by <a href="https://www.theguardian.com/environment/2023/oct/30/weather-tracker-storm-ciaran-rain-uk-france">Storm Ciarán</a>, bringing more extreme winds and heavy rainfall to still-saturated lands.</p>
<p>The UK is no stranger to Atlantic storm systems, but they primarily occur during the winter months. The fact that these severe storms are occurring in autumn is unusual. </p>
<p>Partly this is because an <a href="https://climate.copernicus.eu/record-high-global-sea-surface-temperatures-continue-august">abnormally warm Atlantic Ocean</a> is generating stronger storms (in <a href="https://www.ncei.noaa.gov/access/monitoring/monthly-report/global/202309#:%7E:text=September%202023%20tied%20August%202023,in%20NOAA's%20174%2Dyear%20record.">174 years of data</a>, August and September 2023 were the two months where sea surface temperatures were furthest above the long-term average). Warmer oceans release more moisture into the atmosphere and carry more energy which effectively acts as fuel for storms. </p>
<p>When the tropical Atlantic is warm, storms generated there also change direction, tending to <a href="https://www.nature.com/articles/s41467-019-08496-4">track northward across the ocean before bending to the east</a>. In future, warmer autumns are likely to mean more of these storms <a href="https://theconversation.com/atlantic-hurricane-season-2023-el-nino-and-extreme-atlantic-ocean-heat-are-about-to-clash-204670">sustaining themselves</a> across the Atlantic to hit Western Europe.</p>
<p>Storms are getting stronger elsewhere too. <a href="https://www.theguardian.com/environment/2023/oct/27/hurricane-otis-the-eastern-pacifics-first-inland-category-5-storm">Hurricane Otis</a> recently devastated the Mexican city of Acapulco, for instance. Otis developed from a regular storm into a huge hurricane in record time, and was the first time in history that a hurricane in the Eastern Pacific made landfall and sustained itself as a the strongest “Category 5” storm. <a href="https://www.theguardian.com/environment/2023/oct/23/weather-tracker-tropical-cyclone-tej-approaches-yemen">Tropical Cyclone Tej</a> hit the Arabian Peninsula the week before with 480mm of rainfall in the Al–Ghaydah region in Yemen – eight times the annual average.</p>
<h2>Problems for farms and energy generation</h2>
<p>In unusually warm autumns, extended periods of <a href="https://www.nature.com/articles/s43016-021-00341-6">heat and low rainfall</a> can impact late-season crops such as apples, pears, berries and brassicas. In November 2022, warm and dry weather resulted in the <a href="https://joint-research-centre.ec.europa.eu/jrc-news-and-updates/exceptionally-warm-autumn-raises-concerns-south-europe-2022-11-21_en">early emergence of some winter crops</a> across many European regions. In 2022, China experienced a shock to its autumn yields of <a href="https://www.theguardian.com/world/2022/aug/24/china-issues-alert-drought-heatwave-put-crops-at-risk">wheat and some vegetables</a> following an extended period of drought and elevated temperatures into the Autumn harvesting season.</p>
<p>Energy generation is also increasingly vulnerable to autumn heat. In 2022, a warm autumn meant Europeans used less natural gas for heating, and instead used electricity <a href="https://www.nytimes.com/2022/08/18/world/europe/drought-heat-energy.html">for cooling</a>. Drought adds a <a href="https://www.sciencedirect.com/science/article/pii/S2589004223001074">compounding</a> challenge, as less power can be generated through hydroelectric dams, while less reliable reservoir levels make it harder to schedule generation in advance to <a href="https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/met.2047">coincide with periods of peak demand</a>. In late summer and autumn last year in France, rivers became so warm they were less able to <a href="https://www.theguardian.com/business/2022/aug/03/edf-to-reduce-nuclear-power-output-as-french-river-temperatures-rise">cool down nuclear reactors</a>.</p>
<h2>Autumn as the new summer?</h2>
<p>Tourism is just as vulnerable to unseasonal temperatures. While numbers are often dictated by external factors such as school holidays, extreme summer temperatures will increasingly see people going away <a href="https://joint-research-centre.ec.europa.eu/jrc-news-and-updates/global-warming-reshuffle-europes-tourism-demand-particularly-coastal-areas-2023-07-28_en">in spring and autumn instead</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/559323/original/file-20231114-23-vz69ea.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="White church surrounded by autumn coloured trees" src="https://images.theconversation.com/files/559323/original/file-20231114-23-vz69ea.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559323/original/file-20231114-23-vz69ea.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559323/original/file-20231114-23-vz69ea.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559323/original/file-20231114-23-vz69ea.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559323/original/file-20231114-23-vz69ea.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559323/original/file-20231114-23-vz69ea.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559323/original/file-20231114-23-vz69ea.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">Colourful autumn in New England.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/fall-foliage-stowe-community-church-vermont-208811707">Don Landwehrle / shutterstock</a></span>
</figcaption>
</figure>
<p>Yet even autumn destinations are finding things are changing. New England in the US is known for its spectacular colourful trees at this time of year, yet warming conditions are changing the <a href="https://eu.usatoday.com/story/graphics/2023/09/16/fall-2023-colors-foliage-less-vibrant/70840309007/">timing and vibrancy</a> of its leaf fall. Autumn heat <a href="https://www.science.org/doi/10.1126/science.adf5098">variation</a> could impact the volume of visitors, threatening a <a href="https://www.uvm.edu/news/gund/how-extreme-weather-impacts-fall-foliage#:%7E:text=With%20trees%20set%20to%20reveal,%24800%20million%20in%20Vermont%20alone.">billion dollar</a> tourism industry. </p>
<p>Something similar is being observed in <a href="https://www.sciencedirect.com/science/article/abs/pii/S0261517718301997">Japan</a>, where leaves are staying on trees until later in the year. This can create further hazards, as when trees have <a href="https://www.telegraph.co.uk/environment/2021/11/24/trees-likely-topple-winter-have-not-enough-leaves-warn-forecasters/">more leaf surface area</a> they’re more exposed to destructive wind storms.</p>
<p>These are just some of the effects of an unusually warm autumn, even by current standards. But with summers being extended and more storms and extreme weather in the autumn months seemingly the new norm, we need to start rethinking what weather we can expect at this time of year.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.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">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
<br><em><a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeTop">Get a weekly roundup in your inbox instead.</a> Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. <a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeBottom">Join the 20,000+ readers who’ve subscribed so far.</a></em></p>
<hr><img src="https://counter.theconversation.com/content/216931/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Scott McGrane is affiliated with The British Hydrological Society (Honorary Treasurer).</span></em></p><p class="fine-print"><em><span>Christopher White receives funding from the European Commission through Horizon Europe, the Natural Environment Research Council (NERC), the Engineering and Physical Sciences Research Council (EPSRC), the Scottish Funding Council/Scottish Government and Innovate UK. He is Deputy Editor of the RMetS/Wiley International Journal of Climatology and is an Ordinary Member of the British Hydrological Society.</span></em></p>Relative to the long-term average, this autumn has been even hotter than summer.Scott McGrane, Senior Lecturer in Environmental Change, Department of Economics, University of Strathclyde Christopher J White, Head of the Centre for Water, Environment, Sustainability and Public Health, University of Strathclyde Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2135902023-10-25T10:49:23Z2023-10-25T10:49:23ZHow climate change is affecting the seasons<figure><img src="https://images.theconversation.com/files/555566/original/file-20231024-29-a074ma.jpg?ixlib=rb-1.1.0&rect=8%2C0%2C3686%2C3637&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/beautiful-autumnal-scenery-tree-tunnel-regents-747085630">I Wei Huang/Shutterstock</a></span></figcaption></figure><p>Autumn has finally arrived in the UK following an <a href="https://www.metoffice.gov.uk/binaries/content/assets/metofficegovuk/pdf/weather/learn-about/uk-past-events/interesting/2023/2023_05_september_heatwave.pdf">unusually sunny September</a>. The days are growing shorter, the temperature cooler, and the leaves are changing colour. </p>
<p>The delayed onset of autumn in 2023 is not a one off. It’s actually part of a broader trend in which the shift from summer to winter is happening later in the year. My <a href="https://www.researchgate.net/publication/259844410_C_Jeganathan_J_Dash_and_PM_Atkinson_2014_Remotely_sensed_trends_in_the_phenology_of_northern_high_latitude_terrestrial_vegetation_controlling_for_land_cover_change_and_vegetation_type_Remote_Sensing_o">own research</a> that I’ve carried out over the past 13 years points towards climate change as the likely culprit.</p>
<p>One of the most noticeable effects of climate change is the changing patterns of vegetation seasonality around us. This includes the timing of important biological events such as bud burst, the appearance of the first leaves, flowering and leaf fall.</p>
<p>In general, the appearance of the first leaf marks the arrival of spring, while leaf fall signals the beginning of autumn. The timing of these events is changing, particularly in the northern hemisphere, where spring appears to be starting earlier and autumn’s onset is being delayed.</p>
<p>Traditionally, monitoring vegetation seasonality involved meticulously documenting these seasonal events year after year. The earliest records of spring events in the UK date back to 1736, when naturalist <a href="https://www.britannica.com/science/phenology#:%7E:text=Robert%20Marsham%E2%80%99s%20observations">Robert Marsham</a> began recording the timing of spring events in Norwich, England. </p>
<p>Today, satellite data has become an essential tool for tracking changes in vegetation seasonality. This data can be used to estimate vegetation vigour (an indicator of vegetation’s condition, strength and lushness). Changes can then be used to identify the start and end of each growing season.</p>
<h2>Longer growing seasons</h2>
<p>Climate researchers now have nearly five decades of satellite observations at their disposal. Analysis of this data reveals that spring has advanced by approximately 15 days, while autumn has been delayed by a similar amount. The overall outcome has been the extension of the growing season by an entire month over the past three decades.</p>
<p>The shift in the timing of the seasons is particularly pronounced at higher latitudes. Vegetation situated more than 55° north of the equator, such as in the larch forests of northern Russia, has shown a trend towards an extended growing season, increasing by up to one day per year.</p>
<p>A longer growing season is not necessarily a bad thing. It means a longer period of photosynthesis, which theoretically could boost <a href="https://www.britannica.com/technology/carbon-sequestration">net carbon uptake</a> – although there is <a href="https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2022JG006900">no concrete evidence</a> for this yet.</p>
<p>But an earlier onset of the growing season exposes plants to the risk of damage from spring frosts and an increased vulnerability to summer drought. <a href="https://www.science.org/doi/10.1126/sciadv.aba2724">Research</a> has found that an early spring in central and northern Europe in 2018 promoted increased vegetation growth. This, in turn, contributed to soil losing its moisture quickly, amplifying summer drought conditions.</p>
<figure class="align-center ">
<img alt="A view of a coniferous forest with a sea bay and hills in the distance." src="https://images.theconversation.com/files/555571/original/file-20231024-29-9r2jaf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/555571/original/file-20231024-29-9r2jaf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/555571/original/file-20231024-29-9r2jaf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/555571/original/file-20231024-29-9r2jaf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/555571/original/file-20231024-29-9r2jaf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/555571/original/file-20231024-29-9r2jaf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/555571/original/file-20231024-29-9r2jaf.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 shift in the timing of the seasons is particularly pronounced at higher latitudes.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/beautiful-autumn-landscape-view-larch-trees-2207472441">Andrei Stepanov/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Role of climate change</h2>
<p>Temperature is <a href="https://www.nature.com/articles/nclimate3277">one of the primary factors</a> influencing vegetation growth at high northerly latitudes. So, an earlier onset of spring and a later arrival of autumn are probably driven by the rising global mean temperature. Since 1981, the global mean temperature has increased by <a href="https://www.ncei.noaa.gov/access/monitoring/monthly-report/global/202213">0.18°C per decade</a>.</p>
<p>Nonetheless, the influence of temperature on the duration of the growing season may change depending on the type of vegetation. In ecosystems primarily dominated by forests, a warmer climate <a href="https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2022JG006900">can lead to</a> more photosynthesis and increased vegetation productivity. </p>
<p>On the other hand, in a warmer climate, more water evaporates from the Earth’s surface, drying out the soil. This could adversely affect the growth of plants with shallow roots, such as grasses and herbaceous plants.</p>
<p>Another consequence of climate change is the increased frequency of droughts during the peak of the growing season. Drought conditions result in severe water stress for plants, leading to the premature shedding of leaves or a change in their colour, a phenomenon often referred to as a “false autumn”. </p>
<p>The UK <a href="https://www.bbc.co.uk/news/science-environment-62582186">experienced such conditions</a> in August 2022, when there was an early leaf fall and the browning of leaves, as the country grappled with an <a href="https://www.reuters.com/world/uk/extreme-weather-warning-force-britain-new-heatwave-hits-2022-08-11/">extreme heatwave</a>.</p>
<p>A longer and drier growing season can also increase the risk of forest fires. A <a href="https://www.science.org/doi/10.1126/science.1128834">US study</a> from 2006 revealed a significant surge in wildfire activity within the forests of the northern Rockies from the mid-1980s. This change was closely linked to increased spring and summer temperatures and an earlier spring snowmelt.</p>
<figure class="align-center ">
<img alt="Yellow and orange maple leaves on the ground in the sunlight." src="https://images.theconversation.com/files/555574/original/file-20231024-21-pk0kuk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/555574/original/file-20231024-21-pk0kuk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/555574/original/file-20231024-21-pk0kuk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/555574/original/file-20231024-21-pk0kuk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/555574/original/file-20231024-21-pk0kuk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/555574/original/file-20231024-21-pk0kuk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/555574/original/file-20231024-21-pk0kuk.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">Trees sometimes shed their leaves early when under stress.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/yellow-orange-maple-leaves-forest-on-1988839673">MVolodymyr/Shutterstock</a></span>
</figcaption>
</figure>
<p>Climate change is having a clear impact on vegetation growth and seasonality. But the extent and severity of its impact varies depending on the type of plant and where it grows.</p>
<p>The availability of satellite data spanning the past 50 years is a valuable resource for capturing changes in the duration of the vegetation growing season. This data is helping scientists quantify the scale and consequences of these changes, providing insights into how plants are responding to our warming climate.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.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">
<figcaption>
<span class="caption"></span>
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<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
<br><em><a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeTop">Get a weekly roundup in your inbox instead.</a> Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. <a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeBottom">Join the 20,000+ readers who’ve subscribed so far.</a></em></p>
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<p class="fine-print"><em><span>Jadu Dash 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>Autumn is arriving later in the year – climate change is probably to blame.Jadu Dash, Professor of Remote Sensing in Geography and Environmental Science, University of SouthamptonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2136432023-10-01T19:16:32Z2023-10-01T19:16:32ZOur mood usually lifts in spring. But after early heatwaves and bushfires, this year may be different<p>When we think of spring, we might imagine rebirth and renewal that comes with the warmer weather and longer days. It’s usually a time to celebrate, flock to <a href="https://floriadeaustralia.com">spring flower festivals</a> and spend more time in nature.</p>
<p>Spending time in nature or doing things outside, such as <a href="https://journals.sagepub.com/doi/abs/10.1177/1757913915589845">exercising</a> or <a href="https://www.sciencedirect.com/science/article/pii/S2352827321002093">gardening</a>, <a href="https://www.sciencedirect.com/science/article/abs/pii/S0272494419301185">lifts our mood</a>.</p>
<p>But this year, with an <a href="https://twitter.com/Reuters/status/1704325785627050136">early start</a> to the bushfire season, and the <a href="https://theconversation.com/worried-about-heat-and-fire-this-summer-heres-how-to-prepare-212443">promise of</a> long, hot months ahead, we may see our views about the warmer months start to shift.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1704325785627050136"}"></div></p>
<p>For some people, the coming months are not a celebration. They are something to fear, or feel sad about.</p>
<p>In particular, communities and emergency responders who have experienced bushfires or drought in the past may see rising levels of <a href="https://search.informit.org/doi/pdf/10.3316/ielapa.588776016823324">stress and anxiety</a> as they face the months ahead.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/here-comes-the-sun-how-the-weather-affects-our-mood-19183">Here comes the sun: how the weather affects our mood</a>
</strong>
</em>
</p>
<hr>
<h2>How’s this spring different?</h2>
<p>In recent weeks, the Australian Bureau of Meteorology has <a href="http://www.bom.gov.au/climate/enso/">declared</a> two climate events are now under way: <a href="https://theconversation.com/explainer-el-nino-and-la-nina-27719">El Niño</a> and a positive <a href="http://www.bom.gov.au/climate/iod/">Indian Ocean Dipole</a>. </p>
<p>These events predict warmer, drier conditions through to summer, as well as more intense heatwaves, bushfires and droughts.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1703999811136205005"}"></div></p>
<p>In temperate and subtropical regions, our summers are on average <a href="https://australiainstitute.org.au/wp-content/uploads/2020/12/P834-Out-of-Season-WEB.pdf">becoming</a> hotter and longer, and winters are becoming warmer and shorter. Climate change is the <a href="https://www.csiro.au/en/research/environmental-impacts/climate-change/climate-change-information">primary driver</a> of these shifts.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-el-nino-and-la-nina-27719">Explainer: El Niño and La Niña</a>
</strong>
</em>
</p>
<hr>
<h2>What happens to our mood as the temperature rises?</h2>
<p>Hotter temperatures and prolonged heat is linked to <a href="https://link.springer.com/article/10.1007/s40641-019-00121-2">aggression</a> and <a href="https://link.springer.com/article/10.1007/s00420-010-0534-2">higher rates</a> of emergency hospital admissions due to health conditions, heat-related injuries, and mental health concerns. </p>
<p>After an extreme weather event or disaster, rates of anxiety, depression and post-traumatic stress <a href="https://pubmed.ncbi.nlm.nih.gov/33227944/">rise</a>. </p>
<p>Many Australians have already experienced the psychological and physical <a href="https://journals.sagepub.com/doi/abs/10.1177/00048674221107872">impacts</a> of bushfires, droughts, floods and heatwaves. </p>
<p>For some communities and individuals, experiencing these types of events may mean they are <a href="https://www.sciencedirect.com/science/article/pii/S0887618520301110">more</a> resilient or prepared for the future. For others, the anticipation of rising heat or other climatic threats may cause <a href="https://www.mdpi.com/1660-4601/10/1/1">concern</a>. They may also prompt <a href="https://journals.sagepub.com/doi/full/10.1177/00048674221107872">pre-traumatic stress</a> – the stress that comes ahead of expected loss or trauma.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1466521425888620550"}"></div></p>
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<strong>
Read more:
<a href="https://theconversation.com/worried-about-heat-and-fire-this-summer-heres-how-to-prepare-212443">Worried about heat and fire this summer? Here's how to prepare</a>
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<h2>Anxiety, anger and sadness</h2>
<p>As climate-related events become more widespread, people may also become increasingly affected by feelings such as anxiety, anger and sadness.</p>
<p><a href="https://www.nature.com/articles/s41558-021-01251-y">Climate anxiety</a> refers to the fear, dread and worry about climate change. Anxiety can be a helpful response as it allows us to prepare and respond to future threats. For instance, climate anxiety <a href="https://www.sciencedirect.com/science/article/pii/S0272494422001323">may help prompt</a> pro-environmental behaviour and climate action, such as attending a protest. But this type of anxiety can also become <a href="https://www.sciencedirect.com/science/article/pii/S0887618520300773">overwhelming</a>.</p>
<p>The loss of wildlife and nature due to bushfires can leave people feeling <a href="https://www.mdpi.com/1660-4601/19/4/2461">grief</a> over what’s lost, and <a href="https://www.sciencedirect.com/science/article/pii/S2667278221000018">anger</a> about the lack of action to prevent these losses.</p>
<p>Losses could also be more personal, including damage to health, livelihoods, homes, or even the ability to do enjoyable outdoor activities, such as playing sports or exercising outside.</p>
<p>Another experience, solastalgia, is the “homesickness you have when you are still at home”. <a href="https://pubmed.ncbi.nlm.nih.gov/18027145/#:%7E:text=As%20opposed%20to%20nostalgia%2D%2D,connected%20to%20their%20home%20environment.">Researchers suggest</a> solastalgia is a type of distress when someone perceives negative changes and gradual deterioration to their own home environment. These feelings could arise when we notice seasonal and environmental changes to the places we love and call home.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/youre-not-the-only-one-feeling-helpless-eco-anxiety-can-reach-far-beyond-bushfire-communities-129453">You're not the only one feeling helpless. Eco-anxiety can reach far beyond bushfire communities</a>
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</p>
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<h2>But there are things you can do</h2>
<p>Heading into the hotter months, strong <a href="https://www.sciencedirect.com/science/article/pii/S0887618520301110">community</a> support, cohesion and preparedness may be especially important. There are also things you can do to maintain and manage your mental health and wellbeing. Though more research is needed to understand which strategies work best, health professionals <a href="https://headspace.org.au/assets/Factsheets/headspace_how-to-cope-with-the-stress-of-natural-disasters_Fact-Sheet_FA01_DIGI-1.pdf">suggest</a>:</p>
<ul>
<li><p>connecting with others, especially people you trust and who support your wellbeing </p></li>
<li><p>finding ways to connect with your community either in person (for example, through <a href="https://theconversation.com/how-community-gardening-could-ease-your-climate-concerns-211316">community gardening</a>) or online (for example, via discussion groups)</p></li>
<li><p>being mindful of your physical and psychological safety (for instance, especially during climate-related events) and, if you need it, seeking professional support</p></li>
<li><p>taking a break from distressing media content when needed. </p></li>
</ul>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/keeping-your-cool-in-a-warming-world-8-steps-to-help-manage-eco-anxiety-212174">Keeping your cool in a warming world: 8 steps to help manage eco-anxiety</a>
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</em>
</p>
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<p>Understandably, people may continue to be anxious about the seasons to come with the ongoing threat of climate change.</p>
<p>To avoid becoming overwhelmed, you can also respond to and channel your distressing feelings. You can <a href="https://link.springer.com/article/10.1007/s12144-022-02735-6">take part in</a> community-led climate action projects, and <a href="https://www.sciencedirect.com/science/article/abs/pii/S0272494419301185">spend time outdoors</a> and in nature (even for <a href="https://www.tandfonline.com/doi/abs/10.1080/17439760.2018.1557242">short bursts of time</a>). </p>
<p>These actions might help uphold the positive links between wellbeing and nature, no matter the season.</p>
<hr>
<p><em>If this article has raised issues for you, or if you’re concerned about someone you know, call Lifeline on 13 11 14.</em></p><img src="https://counter.theconversation.com/content/213643/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tara Crandon receives funding from the Child and Youth Mental Health group at QIMR Berghofer Medical Research Institute.</span></em></p>We’ve had an early start to the bushfire season and there’s more to come. No wonder spring isn’t always a celebration.Tara Crandon, Psychologist and PhD Candidate, QIMR Berghofer Medical Research InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2081782023-06-21T08:26:19Z2023-06-21T08:26:19ZWhat is a solstice? An astronomer explains the long and short of days, years and seasons<figure><img src="https://images.theconversation.com/files/533057/original/file-20230621-17-1n2qo0.jpeg?ixlib=rb-1.1.0&rect=14%2C2%2C2000%2C1074&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A long-exposure photo reveals the Sun's path in the sky every day for a six-month period.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/bob_81667/3685994101/in/photolist-6BHFCr-69JwxK-268FbmG-aaWQXU-pBcooC-24tFzQY-6BMFhA-v8vL5v-eRGfBK-dRvGXJ-s817GW-eRGfyP-UD8MVM-8sWtp1-UJPkpe-nNm4ee-R8j67L-7ppJ4P-uKwxzV-6EbSfR-Q6QJuR-i2RtXE-84TFpR-24YVJHB-XHctj3-qHscEu-SbRGEU-vpNikh-7xwAmZ-TgV76V-9iyxng-7WuwZJ-7TWser-2ivLNBZ-8ccUBu-95mNez-8pMDw9-sRbs1i-7gJh5w-KE9aZo-93NQ78-obiiEs-25fsiAp-7NdofV-8ccUAS-qYdhiX-sg9cvh-PbbZpP-9uPEaM-sg9jm1">Bob Fosbury / Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Happy solstice everyone! The mid-year solstice in 2023 falls at 2:58 pm UTC on 21 June (or, in more advanced time zones like the one I’m writing from, in the early hours of 22 June).</p>
<p>Depending on where you are reading this, this will either be your winter solstice (for those in the southern hemisphere) or the summer solstice (for our northern readers). </p>
<p>But what is the solstice? What does it mean for our day-to-day lives? Well the answer all boils down to orbits – the way Earth whirls and wobbles as it wends its way around the Sun.</p>
<h2>The seasons: the result of a moving platform</h2>
<p>Earth is a moving platform – orbiting the Sun in a little more than 365 days. Despite our incredible orbital speed (around 30 kilometres per second), we don’t feel this motion. Instead, it appears to us as though the Sun is moving through the year.</p>
<p>Imagine for a moment you could remove Earth’s atmosphere, revealing the background stars at the same time as the Sun. Those stars, incredibly distant, rise and set every 23 hours, 56 minutes and 4 seconds - the true rotation period of Earth. </p>
<p>The Sun, though, rises and sets roughly every 24 hours – making the “solar day” 3 minutes and 56 seconds longer than Earth’s true rotation period.</p>
<p>That difference is the result of the Sun’s apparent motion against the background stars. From our imaginary airless Earth, we would see the Sun gradually sliding through the constellations of the zodiac, making one full lap of the sky in one year.</p>
<p>But things are a little more complicated. You see, our moving platform is tipped over, tilted on its side by about 23.5 degrees. </p>
<p>As we move around the Sun, our planet alternately tilts one hemisphere towards our star, then away again. This is the cause of the seasons.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533048/original/file-20230621-19-qd6khy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A diagram showing the Earth going around the Sun with the equinoxes and solstices marked." src="https://images.theconversation.com/files/533048/original/file-20230621-19-qd6khy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533048/original/file-20230621-19-qd6khy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=440&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533048/original/file-20230621-19-qd6khy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=440&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533048/original/file-20230621-19-qd6khy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=440&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533048/original/file-20230621-19-qd6khy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=553&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533048/original/file-20230621-19-qd6khy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=553&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533048/original/file-20230621-19-qd6khy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=553&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 length of the day changes over the year due to the slight tilt in the Earth’s axis.</span>
<span class="attribution"><a class="source" href="https://media.bom.gov.au/social/blog/1762/solstices-and-equinoxes-the-reasons-for-the-seasons/">Bureau of Meteorology</a></span>
</figcaption>
</figure>
<p>When your hemisphere is tilted towards the Sun, you have summer – long days, with the noonday Sun high in the sky. Six months later, when you are tilted away, you have winter – the noonday Sun is low, days are shorter, and there is a chill in the air.</p>
<p>Between those extremes, the Sun gradually drifts north and south. At the extremes of its motion, it would be overhead from 23.5° north of the Equator (northern hemisphere midsummer) or 23.5° south (southern midsummer).</p>
<p>In total, then, the Sun’s motion moves it between two extremes some 47° apart. Low in the sky in winter, and high in summer.</p>
<h2>So what are the solstices?</h2>
<p>The two solstices are the points at which the Sun is either the farthest north in the sky (which is what we have today), or at its most southerly location.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533097/original/file-20230621-27-8ewjod.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map of the night sky showing the path of the Sun as it movesa against the background stars" src="https://images.theconversation.com/files/533097/original/file-20230621-27-8ewjod.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533097/original/file-20230621-27-8ewjod.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=429&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533097/original/file-20230621-27-8ewjod.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=429&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533097/original/file-20230621-27-8ewjod.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=429&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533097/original/file-20230621-27-8ewjod.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=539&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533097/original/file-20230621-27-8ewjod.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=539&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533097/original/file-20230621-27-8ewjod.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=539&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 map of the entire night sky, like a map of the Earth, showing (in red) the path followed by the Sun through the course of the year - a path known as the ‘ecliptic’.</span>
<span class="attribution"><span class="source">Pablo Carlos Budassi/Wikipedia</span></span>
</figcaption>
</figure>
<p>When the Sun is farthest north in the sky, it will appear lowest in the sky at noon from locations in the southern hemisphere. This also means the shortest period of daylight of the calendar year.</p>
<p>For the northern hemisphere, the situation is reversed – the summer solstice places the noonday Sun high in the sky, with the longest period of daylight of the year.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-the-sunrise-is-still-later-after-the-winter-solstice-shortest-day-77628">Why the sunrise is still later after the winter solstice shortest day</a>
</strong>
</em>
</p>
<hr>
<p>In six months’ time, on December 22 this year, we will have the other solstice – marking the point at which the Sun is at its most southerly point in the sky. That will bring with it the longest day for those in the southern hemisphere, and the shortest for those in the north.</p>
<p>It’s easy to find out when the Sun will rise and set at your location. Many websites provide this information these days - <a href="https://www.timeanddate.com/sun/australia/toowoomba">here, for example, is all that information</a> for my home town – Toowoomba, in southeast Queensland.</p>
<h2>Defining the seasons: climate or cosmology?</h2>
<p>To an astronomer, and to many people around the world, today marks the change of the seasons. In the southern hemisphere, it is the first day of winter. In the north, the first of summer. </p>
<p>Strangely, the solstices are also known as midsummer’s day and midwinter’s day – which leads to the strange idea that winter starts at midwinter!</p>
<p>By this astronomical definition for the seasons, summer runs from midsummer to the autumnal equinox (when the Sun crosses the Equator). Autumn runs from that equinox to midwinter’s day. Winter goes from midwinter to the spring equinox, and spring goes from the spring equinox through to midsummer.</p>
<p><iframe id="XR0EX" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/XR0EX/1/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>In Australia, however, most people are familiar with seasons beginning on the first day of the months of March, June, September and December.</p>
<p>The reason is down to how our climate behaves. In a simple universe, one would expect the longest day to be the hottest (with most time for the Sun to heat the Earth) and the shortest day to be the coldest (the most hours of darkness for things to cool down). </p>
<p>However, things are somewhat more complex. The atmosphere, the ground, and particularly the oceans, take a long time to heat up and to cool down. The result? The warmest time of the year for many places (but not all!) comes a few weeks after midsummer. </p>
<p>While the days are getting shorter, the ocean, ground and air continue to warm up. Similarly, the coldest time in winter is usually a few weeks after midwinter.</p>
<p>Our concept of summer (rather than the astronomer’s definition) is built around this. We think of the middle of summer being the hottest time of year, and the middle of winter being the coldest. </p>
<p><iframe id="txPHo" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/txPHo/3/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<h2>There’s always another secret</h2>
<p>Before I leave you to enjoy the rest of the year’s shortest (or longest) day, there’s one extra cool fact about the seasons that most people don’t appreciate. We imagine the seasons are of equal length - three months of each, in a 12-month year.</p>
<p>But we forget. Not all months are alike. Some are shorter than others (poor February). </p>
<p>Look at a calendar, and add up the days in each astronomical season, and you find something surprising. </p>
<p>The southern hemisphere summer (northern winter), from December 22 to March 21, lasts just 89 days. The southern winter (northern summer), by contrast, is almost 94 days long! </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-messy-history-of-our-modern-western-calendar-170780">The messy history of our modern, Western calendar</a>
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</em>
</p>
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<p>The southern autumn (March to June) is almost 93 days long, while the northern autumn (September to December) is only 90 days.</p>
<p>The reason behind these variations is, once again, all down to Earth’s orbit. As we move around the Sun, the distance to our star varies slightly. </p>
<p>Sometimes, we are closer to our star, and Earth moves faster in its orbit. At other times, we are more distant, and move slower.</p>
<p>In just a couple of weeks time, on July 7, Earth will reach its farthest point from the Sun, which astronomers call “aphelion”. On that date, we will be more than 152 million kilometres from our star. </p>
<p>Six months later, on January 3 2024, we will be at our closest to the Sun – “perihelion” – just over 147 million kilometres distant.</p>
<p>This really highlights one of the beauties of astronomy. Simply put – there’s always another secret – the deeper you look into something, the more beautiful complexity you will find. </p>
<p>So here’s to another 93 days of winter!</p><img src="https://counter.theconversation.com/content/208178/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jonti Horner 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 longest and shortest days of the year are marked by the Sun’s position in the sky – but the seasons lag behind.Jonti Horner, Professor (Astrophysics), University of Southern QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1963442022-12-20T13:37:24Z2022-12-20T13:37:24ZWhy winter solstice matters around the world: 4 essential reads<figure><img src="https://images.theconversation.com/files/501913/original/file-20221219-22-ai6626.jpg?ixlib=rb-1.1.0&rect=3%2C1%2C1019%2C769&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Stonehenge has long been the site of some of the most famous solstice celebrations. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/drone-point-of-view-of-the-sun-rising-over-stonehenge-on-news-photo/1366013168?phrase=winter%20solstice%20stonehenge&adppopup=true">Chris Gorman/Getty Images News</a></span></figcaption></figure><p>If you’ve already spend hours shoveling snow this year, you may be dismayed to realize that technically, it’s not yet winter. According to the astronomical definition, the season will officially begin in the Northern Hemisphere on <a href="https://aa.usno.navy.mil/calculated/seasons?year=2022&tz=5&tz_sign=-1&tz_label=false&dst=false&submit=Get+Data">Dec. 21, 2022</a>: the shortest day of the year, known as the winter solstice.</p>
<p>The weeks leading up to the winter solstice can feel long as days grow shorter and temperatures drop. But it’s also traditionally been a time of renewal and celebration – little wonder that so many cultures mark major holidays just around this time. </p>
<p>Here at The Conversation, we’ve rounded up four of our favorite stories on the solstice: from what it really is to how it’s been commemorated around the world.</p>
<h2>1. Journey of the Sun</h2>
<p>First things first: What is the winter solstice?</p>
<p>For starters, it’s not the day with the latest sunrise or the earliest sunset. Rather, it’s when “the Sun appears the lowest in the Northern Hemisphere sky and is at its farthest southern point over Earth,” <a href="https://theconversation.com/what-you-need-to-know-about-this-years-winter-solstice-and-the-great-conjunction-152224">wrote William Teets</a>, <a href="https://dyer.vanderbilt.edu/about-us/our-staff/">an astronomer</a> at Vanderbilt University. “After that, the Sun will start to creep back north again.” </p>
<p>In the Southern Hemisphere, meanwhile, Dec. 21, 2022 marks the summer solstice. Its winter solstice will arrive June 21, 2023, the same day the Northern Hemisphere celebrates its summer solstice.</p>
<p>“Believe it or not,” Teets added, “we are closest to the Sun in January”: a reminder that seasons come from the Earth’s axial tilt at any given time, not from its distance from our solar system’s star.</p>
<p><img src="https://cdn.theconversation.com/static_files/files/1401/sun_over_here_2.gif?1608652248"></p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-you-need-to-know-about-this-years-winter-solstice-and-the-great-conjunction-152224">What you need to know about this year's winter solstice and the great conjunction</a>
</strong>
</em>
</p>
<hr>
<h2>2. Ancient astronomy</h2>
<p>Many Americans picturing winter solstice celebrations may immediately think of Stonehenge, but cultures have honored the solstice much closer to home. Many Native American communities have long held solstice ceremonies, explained University of Illinois Urbana-Champaign scholar Rosalyn LaPier, <a href="https://history.illinois.edu/directory/profile/rrlapier">an Indigenous writer, ethnobotanist and environmental historian</a>.</p>
<p>“For decades, scholars have studied the astronomical observations that ancient indigenous people made and sought to understand their meaning,” <a href="https://theconversation.com/what-winter-solstice-rituals-tell-us-about-indigenous-people-108327">LaPier wrote</a>. Some societies in North America expressed this knowledge through constructions at special sites, such as Cahokia in Illinois – temple pyramids and mounds, similar to those the Aztecs built, which align with the Sun on solstice days.</p>
<p>“Although some winter solstice traditions have changed over time, they are still a reminder of indigenous peoples’ understanding of the intricate workings of the solar system,” she wrote, and their “ancient understanding of the interconnectedness of the world.”</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-winter-solstice-rituals-tell-us-about-indigenous-people-108327">What winter solstice rituals tell us about indigenous people</a>
</strong>
</em>
</p>
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<h2>3. Dazzling light</h2>
<p>Rubén Mendoza, <a href="https://works.bepress.com/rubn-mendoza/">an archaeologist</a> at California State University, Monterey Bay, made an accidental discovery years ago at a mission church. In this worship space and many others that Catholic missionaries built during the Spanish colonial period, the winter solstice “triggers an extraordinary rare and fascinating event,” <a href="https://theconversation.com/a-sacred-light-in-the-darkness-winter-solstice-illuminations-at-spanish-missions-70250">he explained</a>: “a sunbeam enters each of these churches and bathes an important religious object, altar, crucifix or saint’s statue in brilliant light.”</p>
<figure class="align-center ">
<img alt="A ray of light illuminates golden touches on a tabernacle at the front of a church." src="https://images.theconversation.com/files/150557/original/image-20161216-26123-pe0aox.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/150557/original/image-20161216-26123-pe0aox.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/150557/original/image-20161216-26123-pe0aox.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/150557/original/image-20161216-26123-pe0aox.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/150557/original/image-20161216-26123-pe0aox.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/150557/original/image-20161216-26123-pe0aox.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/150557/original/image-20161216-26123-pe0aox.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">Winter solstice illumination of the main altar tabernacle of the Spanish Royal Presidio Chapel, Santa Barbara, Calif.</span>
<span class="attribution"><span class="source">Rubén G. Mendoza</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>These missions were built to convert Native Americans to Catholicism – people whose cultures had already, for thousands of years, celebrated the solstice Sun’s seeming victory over darkness. Yet the missions incorporated those traditions in a new way, channeling the Sun’s symbolism into a Christian message.</p>
<p>“These events offer us insights into archaeology, cosmology and Spanish colonial history,” Mendoza wrote. “As our own December holidays approach, they demonstrate the power of our instincts to guide us through the darkness toward the light.”</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-sacred-light-in-the-darkness-winter-solstice-illuminations-at-spanish-missions-70250">A sacred light in the darkness: Winter solstice illuminations at Spanish missions</a>
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</em>
</p>
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<h2>4. Victory over darkness</h2>
<p>Our next story goes halfway around the world, describing the Persian solstice festival of Yalda. But it’s also an American story. Growing up in Minneapolis, <a href="https://www.umt.edu/provost/about/about-the-provost.php">anthropologist Pardis Mahdavi</a> explained, she felt a bit left out as neighbors celebrated Hanukkah and Christmas. That’s when her grandmother introduced her to their family’s Yalda traditions.</p>
<p>Millions of people around the world celebrate Yalda, which marks the sunrise after the longest night of the year. “Ancient Persians believed that evil forces were strongest on the longest and darkest night of the year,” <a href="https://theconversation.com/a-persian-festival-yalda-celebrates-the-triumph-of-light-over-darkness-with-pomegranates-poetry-and-sacred-rituals-173969">wrote Mahdavi</a>, who is now provost at the University of Montana. Families stayed up throughout the night, snacking and telling stories, then celebrating “as the light spilled through the sky in the moment of dawn.”</p>
<figure class="align-center ">
<img alt="A photograph from above of two women in headscarves arranging colorful fruit on a blanket." src="https://images.theconversation.com/files/501914/original/file-20221219-16-6hbnxe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/501914/original/file-20221219-16-6hbnxe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/501914/original/file-20221219-16-6hbnxe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/501914/original/file-20221219-16-6hbnxe.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/501914/original/file-20221219-16-6hbnxe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/501914/original/file-20221219-16-6hbnxe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/501914/original/file-20221219-16-6hbnxe.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">Yalda celebrates the sunrise after the longest night of the year.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/two-females-preparing-food-decorated-table-royalty-free-image/857437630?phrase=jasmin%20merdan%20yalda&adppopup=true">Jasmin Merdan/Moment via Getty Images</a></span>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/a-persian-festival-yalda-celebrates-the-triumph-of-light-over-darkness-with-pomegranates-poetry-and-sacred-rituals-173969">A Persian festival, Yalda, celebrates the triumph of light over darkness, with pomegranates, poetry and sacred rituals</a>
</strong>
</em>
</p>
<hr>
<p><em>Editor’s note: This story is a roundup of articles from The Conversation’s archives. The article has been updated to include the date of the summer and winter solstices in the Southern Hemisphere.</em></p><img src="https://counter.theconversation.com/content/196344/count.gif" alt="The Conversation" width="1" height="1" />
The dead of winter, when the longest night of the year takes place, has also traditionally been celebrated as a time of renewal and reverence.Molly Jackson, Religion and Ethics EditorLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1938302022-11-21T19:04:34Z2022-11-21T19:04:34ZWhat planting tomatoes shows us about climate change<figure><img src="https://images.theconversation.com/files/496342/original/file-20221121-14-xam3br.jpg?ixlib=rb-1.1.0&rect=56%2C96%2C5321%2C3499&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>There’s a piece of gardening lore in my hometown which has been passed down for generations: never plant your tomatoes before Show Day, which, in Tasmania, is the fourth Saturday in October. If you’re foolhardy enough to plant them earlier, your tomato seedlings will suffer during the cold nights and won’t grow.</p>
<p>But does this kind of seasonal wisdom still work as the climate warps? We often talk about climate change in large-scale ways – how much the global average surface temperature will increase. </p>
<p>Nations are trying to keep the temperature rise well under 2°C. Taken as an average, that sounds tiny – after all, the temperature varies much more than that when day gives way to night. But remember – before the industrial revolution, the world’s average surface temperature was 12.1°C. Now it’s almost a degree hotter – and could be up to 3°C hotter by the end of the century if high emissions continue. </p>
<p>For many of us, climate change can seem abstract. But the natural world is very sensitive to temperature change. Wherever we look, we can see that the seasons are changing. Gardening lore no longer holds. Flowering may happen earlier. Many species have to move or die. Here’s what you might notice. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/496376/original/file-20221121-20-bebq50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="nothofagus colour change" src="https://images.theconversation.com/files/496376/original/file-20221121-20-bebq50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/496376/original/file-20221121-20-bebq50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/496376/original/file-20221121-20-bebq50.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/496376/original/file-20221121-20-bebq50.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/496376/original/file-20221121-20-bebq50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/496376/original/file-20221121-20-bebq50.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/496376/original/file-20221121-20-bebq50.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>
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<span class="caption">Seasons shifting: Tasmanias southern beech is Australias only native temperate deciduous tree.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Spring is coming earlier</h2>
<p>Warmer temperatures mean spring is arriving earlier and earlier. In Australia, it’s also now five days shorter than the 1950–1969 period, according to Australia Institute <a href="https://australiainstitute.org.au/report/out-of-season/">research</a>. Trees and plants put out new leaves <a href="https://www.abc.net.au/news/science/2015-09-24/will-global-warming-keep-pushing-spring-into-winter/6798082">days earlier</a>. </p>
<p>For some Australian plants, earlier spring means early flowering and fruiting – an average of 9.7 days earlier <a href="https://theconversation.com/early-birds-how-climate-change-is-shifting-time-for-animals-and-plants-34766">per decade</a>. </p>
<p>Japan’s famous spring cherry blossoms are <a href="https://www.bbc.com/news/world-asia-56574142">blooming earlier</a> than they have in centuries. The cherry blossom peak last year was the earliest recorded bloom in a data record going back to the year 812. </p>
<p>Not only are flowers blooming earlier, birds are also <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1474-919X.2005.00380.x">migrating earlier</a>, and may also be delaying their <a href="https://peerj.com/articles/8975/">autumn migrations</a>.</p>
<h2>Summer is getting hotter and longer</h2>
<p>A hotter planet means hotter and longer summers. </p>
<p>It might not feel like it this year with all the rain, but the overall trend is clear. In turn, this means bushfire risk is growing <a href="https://www.climatecouncil.org.au/not-normal-climate-change-bushfire-web/">year on year</a>, with more days of high to catastrophic fire danger. Every year for the last three decades, an <a href="https://theconversation.com/australias-black-summer-of-fire-was-not-normal-and-we-can-prove-it-172506">extra 48,000 hectares</a> of forest has burnt across Australia. </p>
<p>Longer fire seasons are making it harder to schedule fuel reduction burns, and reducing the amount of time for firefighters to rest and recover between fire seasons.</p>
<p>Hotter temperatures are already posing challenges for salmon farmers in Tasmania. Atlantic salmon grow best in <a href="https://thefishsite.com/articles/can-salmon-farming-cope-with-climate-change">cold water</a> and climate change has already pushed ocean temperatures up. In summers now, the waters around Tasmania are <a href="https://www.imas.utas.edu.au/news/news-items/new-research-shows-impact-of-rising-ocean-temperatures-on-atlantic-salmon-physiology">close to the fish’s limit</a>. Warmer summers will be a substantial challenge for salmon farmers in the future. </p>
<p>Hotter water has also killed off <a href="https://theconversation.com/can-selective-breeding-of-super-kelp-save-our-cold-water-reefs-from-hotter-seas-170271">almost all</a> Tasmania’s giant kelp, and made it possible for warm-water fish to migrate south. </p>
<p>For millennia, the North Pole has been covered by sea ice. This, too, is changing. Arctic sea ice is melting earlier in summer and <a href="https://iopscience.iop.org/article/10.1088/1748-9326/aafb84">freezing later in winter</a>. As warming intensifies, the central Arctic is likely to go from permanent ice cover to ice free <a href="https://www.nature.com/articles/s43247-021-00183-x">over summer</a> by 2100.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/australias-black-summer-of-fire-was-not-normal-and-we-can-prove-it-172506">Australia's Black Summer of fire was not normal – and we can prove it</a>
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</em>
</p>
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<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/496343/original/file-20221121-18-7mqpih.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="tasmania salmon farms" src="https://images.theconversation.com/files/496343/original/file-20221121-18-7mqpih.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/496343/original/file-20221121-18-7mqpih.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=391&fit=crop&dpr=1 600w, https://images.theconversation.com/files/496343/original/file-20221121-18-7mqpih.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=391&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/496343/original/file-20221121-18-7mqpih.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=391&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/496343/original/file-20221121-18-7mqpih.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=491&fit=crop&dpr=1 754w, https://images.theconversation.com/files/496343/original/file-20221121-18-7mqpih.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=491&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/496343/original/file-20221121-18-7mqpih.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=491&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Salmon farming only works if the water is cold – and that poses problems for a major Tasmanian industry.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Autumn is falling behind</h2>
<p>At the beginning of autumn, the leaves of nothofagus, Australia’s only <a href="https://www.abc.net.au/news/science/2016-03-07/deciduous-trees-in-australia/7200608">temperate deciduous tree</a>, change colour and fall to the ground, just as many Northern Hemisphere trees do. </p>
<p>Here, too, we can see the climate changing. Around the world, warmer temperatures and rising atmospheric carbon dioxide are <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2486.2007.01473.x">delaying the arrival</a> of <a href="https://www.nationalgeographic.com/environment/article/fall-foliage-disrupted-by-climate-change-might-be-new-normal">autumn colours</a> by up to a month.</p>
<h2>Winter is disappearing</h2>
<p>Alpine species such as the mountain pygmy possum have life cycles built around winter snow, while many of the world’s cities rely on snow melt for their water supply. In Australia, snowfall has <a href="https://www.climatechange.environment.nsw.gov.au/snow">been decreasing</a> in recent decades. </p>
<p>In a warmer world, there’s less snow and ice. That’s <a href="https://www.theguardian.com/environment/2022/apr/11/santiago-chile-ration-water-drought">posing major challenges</a> for cities like Santiago in Chile, as well as semi-arid areas in the United States which have <a href="https://www.discovermagazine.com/environment/how-the-u-s-megadrought-will-affect-2022-and-beyond">relied on snowmelt</a>. </p>
<h2>Species are on the move</h2>
<p>What else might you notice? Different animals, birds, fish and plants. Not only are the seasons changing, but many species are now found in areas they could never have survived before. </p>
<p>Tropical corals have now been found <a href="https://link.springer.com/article/10.1007/s00338-018-1727-5">happily growing near Sydney</a>. Coral reef fish, too, are heading south to areas well outside their <a href="https://www.frontiersin.org/articles/10.3389/fmars.2018.00031/full">historic range</a>. </p>
<p>You can see some of the surprising new finds on the citizen science project <a href="https://www.redmap.org.au">Redmap</a>, such as sightings of the tropical <a href="https://www.redmap.org.au/sightings/4157/">yellow bellied sea snake</a> in Tasmanian waters.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/thousands-of-photos-captured-by-everyday-australians-reveal-the-secrets-of-our-marine-life-as-oceans-warm-189231">Thousands of photos captured by everyday Australians reveal the secrets of our marine life as oceans warm</a>
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</em>
</p>
<hr>
<p>For First Australians, climate change brings a different upheaval. The seasonal link between, say, a wattle flowering and the arrival of fish species is <a href="https://theconversation.com/shifting-seasons-using-indigenous-knowledge-and-western-science-to-help-address-climate-change-impacts-183229">breaking down</a>. </p>
<h2>Changes everywhere</h2>
<p>Climate change really does mean change – both large scale and small. From extreme weather to ecosystems changing all the way through to the time when you can plant tomatoes. </p>
<p>For gardeners, this means accepted wisdom no longer holds. In Tasmania, you can now safely plant tomatoes 18 days earlier than you could in the 1900s. That’s because minimum temperatures in October are now <a href="http://www.bom.gov.au/climate/change/index.shtml#tabs=Tracker&tracker=timeseries&tQ=graph%3Dtmin%26area%3Dtas%26season%3D10%26ave_yr%3D10">about 1°C</a> warmer than they were in 1910. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/494010/original/file-20221108-13-bwjxqv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/494010/original/file-20221108-13-bwjxqv.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=404&fit=crop&dpr=1 600w, https://images.theconversation.com/files/494010/original/file-20221108-13-bwjxqv.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=404&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/494010/original/file-20221108-13-bwjxqv.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=404&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/494010/original/file-20221108-13-bwjxqv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=508&fit=crop&dpr=1 754w, https://images.theconversation.com/files/494010/original/file-20221108-13-bwjxqv.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=508&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/494010/original/file-20221108-13-bwjxqv.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=508&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Hobart’s daily minimum temperature in October for three time periods: 1882-present, 1882-1990, and 1990-present. The last 30 years have been much warmer on average than the years before.</span>
</figcaption>
</figure>
<p>Climate change is altering our seasons and changing our world in both obvious and subtle ways. </p>
<p>So while planting tomatoes may seem like a trivial example, it’s yet another sign of the climate changing all around us. It’s no longer a problem for the far-off future. It’s our problem, now.</p><img src="https://counter.theconversation.com/content/193830/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Edward Doddridge 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>It can be hard to grasp the changes climate change is bringing. To see it in your own life, look at the shifting seasons.Edward Doddridge, Research Associate in Physical Oceanography, University of TasmaniaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1913002022-10-24T12:27:11Z2022-10-24T12:27:11ZHalloween’s celebration of mingling with the dead has roots in ancient Celtic celebrations of Samhain<figure><img src="https://images.theconversation.com/files/489639/original/file-20221013-22-tnrhsg.jpg?ixlib=rb-1.1.0&rect=22%2C25%2C2095%2C1384&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">How did Halloween get associated with the spooky?</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/group-of-friends-dancing-together-royalty-free-image/1144985881?phrase=halloween%20party&adppopup=true">SolStock/Collection E+ via Getty Images</a></span></figcaption></figure><p>As Halloween approaches, people get ready to celebrate the spooky, the scary and the haunted. Ghosts, zombies, skeletons and witches are prominently displayed in yards, windows, stores and community spaces. Festivities center around the realm of the dead, and some believe that the dead might actually mingle with the living on the night of Halloween. </p>
<p>Scholars have often noted how these modern-day celebrations of Halloween have origins in Samhain, a festival <a href="https://theconversation.com/tricking-and-treating-has-a-history-85720">celebrated by ancient Celtic cultures</a>. In contemporary Irish Gaelic, <a href="https://www.focloir.ie/en/dictionary/ei/O%C3%ADche+Shamhna">Halloween is still known as Oíche Shamhna, or Eve of Samhain</a></p>
<hr>
<iframe id="noa-web-audio-player" style="border: none" src="https://embed-player.newsoveraudio.com/v4?key=x84olp&id=https://theconversation.com/halloweens-celebration-of-mingling-with-the-dead-has-roots-in-ancient-celtic-celebrations-of-samhain-191300&bgColor=F5F5F5&color=D8352A&playColor=D8352A" width="100%" height="110px"></iframe>
<p><em>You can listen to more articles from The Conversation, narrated by Noa, <a href="https://theconversation.com/us/topics/audio-narrated-99682">here</a>.</em></p>
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<p>As a <a href="https://dornsife.usc.edu/cf/faculty-and-staff/faculty.cfm?pid=1012737">folklorist with a special interest in Celtic culture</a>, I find it interesting to note the longevity of this holiday: The celebration of the dead on Halloween is not a recent innovation, but rather one of the oldest surviving traditions that continues today as a vibrant part of many peoples’ lives.</p>
<h2>Early evidence from archaeology</h2>
<p>In ninth century Irish literature, Samhain is mentioned many times as an integral part of the Celtic culture. It was <a href="https://sites.uwm.edu/barnold/2001/10/31/halloween-customs-in-the-celtic-world/">one of four seasonal turning points</a> in the Celtic calendar, and perhaps the most important one. It signaled the end of the light half of the year, associated with life, and the beginning of the dark half, associated with the dead. </p>
<p>Archaeological records suggest that commemorations of Samhain can be traced back to the <a href="https://www.nationalgeographic.com/travel/article/inside-irelands-gate-to-hell-that-birthed-halloween">Neolithic period, some from 6,000 years ago</a>. Neolithic Ireland had no towns or cities, but did craft huge architectural monuments, which acted as seasonal gathering spots, and housed the remains of the societies’ elites. </p>
<p>These megalithic sites, from the Greek “mega” and “lithos,” meaning big stone, would at times host vast numbers of people, gathered together for brief periods around specific calendar dates. Archaeological records reveal evidence of massive feasts, yet little to no evidence of domestic use. If people did live year-round at these sites, they would have been a select few.</p>
<p>Data from animal bones can reveal approximate time periods of the feasts, and further data comes from the monuments themselves. Not only are the monuments situated in key places in the landscape, but they are also carefully celestially aligned to allow the sun or moon to shine directly into the center of the monument on a particular day.</p>
<p>These sites connect the landscape to the cosmos, creating a lived calendar, scripted in stone. The UNESCO World Heritage monument of Newgrange, for example, is built so that a <a href="https://www.worldheritageireland.ie/bru-na-boinne/built-heritage/newgrange/">shaft of sunlight illuminates the innermost chamber</a> precisely on the day of winter solstice. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/489642/original/file-20221013-13-phcvnq.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A front view of the Newgrange monument in Ireland taken from outside the grounds." src="https://images.theconversation.com/files/489642/original/file-20221013-13-phcvnq.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/489642/original/file-20221013-13-phcvnq.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/489642/original/file-20221013-13-phcvnq.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/489642/original/file-20221013-13-phcvnq.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/489642/original/file-20221013-13-phcvnq.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/489642/original/file-20221013-13-phcvnq.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/489642/original/file-20221013-13-phcvnq.jpeg?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>
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<span class="caption">Ancient monuments such as the Newgrange have been carefully celestially aligned.</span>
<span class="attribution"><a class="source" href="https://upload.wikimedia.org/wikipedia/commons/0/0f/Irelands_history.jpg">Tjp finn via Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>Less than 30 miles away lies the hill of Tara, another massive megalithic site. The Mound of Hostages, the oldest extant megalithic structure at Tara, <a href="https://www.worldhistory.org/Samhain/">is aligned to Samhain</a>. Tara is known as the traditional spiritual and political capital of Ireland, and here, too, archaeologists have found evidence of <a href="http://www.jstor.org/stable/archirel.34.1">mass seasonal gatherings of people, with the remains of feasts and great bonfires</a>.</p>
<h2>The spirits of the dead</h2>
<p>According to early Irish literature, as well as traditional folklore collected in the 19th century, Samhain of long ago was a time for people to come together, under a command of peace, to feast, tell stories, make social and political claims, engage in important sacred rituals and, perhaps most importantly, <a href="https://www.worldhistory.org/Samhain/">to commune with the dead</a>. </p>
<p>The traditional, pre-Christian realm of the dead was referred to as the Otherworld. The Otherworld was not somewhere far away, but rather overlapping with the world of the living. The Irish beliefs about the Otherworld were detailed and complex. It is full of magic, of witchcraft, of speaking with the dead as well as <a href="https://sites.uwm.edu/barnold/2001/10/31/halloween-customs-in-the-celtic-world/">seeing into the future</a>. The dead were traditionally believed to continue to see the living, although the living could only occasionally see them. The most prominent occasion would be on Samhain itself, when lines between the Otherworld of the dead and the realm of the living were weakened.</p>
<p>Not only were there particular days that one might encounter the dead, but particular places as well, these being the same megalithic sites. These sites are known in Irish Gaelic as “sí” sites, but there is another meaning of the word sí in Irish, <a href="https://www.teanglann.ie/en/fgb/s%c3%ad">that being the spirits of the mounds</a>. This is often translated into English as “fairies”, which loses a great deal of meaning. “Fairies” in Ireland are spirits deeply connected with the realm of the dead, the mounds, and, perhaps most especially, Samhain. </p>
<p>The connection can be witnessed in the figure of the banshee – or bean sí, in Irish – an important mythological figure in Irish folklore, believed to be heard wailing with grief directly before the death of a family member. With Irish “bean” meaning simply “woman”, the <a href="https://www.jstor.org/stable/20177501">banshee is thus a female spirit of the mounds</a>, and a ruler of the realm of the dead. </p>
<p>The sí spirits are not only spirits of the dead, but they are also a particular aristocracy of the dead, who host the dead with feasting, merriment and eternal youth, often at the age-old megalithic sites. In Irish lore, they are powerful and dangerous, able to give great gifts or exact great damage. They once ruled Ireland, according to folklore, and now they rule the world of the dead.</p>
<p>The Otherworld is always there, but it is on the beginning of the dark half of the year, the evening of Samhain, now Halloween, when the dead are at their most powerful and when the lines between this world and the next are erased.</p>
<p>As the light of summer fades and the season of darkness begins, the ancient holiday of Halloween continues to celebrate the dead mingling with the world of the living once again, as it has for thousands of years.</p><img src="https://counter.theconversation.com/content/191300/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tok Thompson 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>A folklorist explains how Halloween continues an ancient Celtic tradition of the celebration of the dead.Tok Thompson, Professor of Anthropology, USC Dornsife College of Letters, Arts and SciencesLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1850212022-06-21T02:57:04Z2022-06-21T02:57:04ZWhere do all the mosquitoes go in the winter?<figure><img src="https://images.theconversation.com/files/469915/original/file-20220621-17-wrrp6a.jpg?ixlib=rb-1.1.0&rect=77%2C240%2C5044%2C3205&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/iuJgEBVSRIo?utm_source=unsplash&utm_medium=referral&utm_content=creditShareLink">Cameron Webb/NSW Health Pathology</a>, <span class="license">Author provided</span></span></figcaption></figure><p>Summer evenings by the pool, lake or BBQ mean mosquitoes. But what about during winter when we’re mostly indoors? As the weather cools, these bloodsucking pests are rarely seen. </p>
<p>But where do they go?</p>
<h2>Warm, wet conditions suit mosquitoes</h2>
<p>Mosquitoes have complex life cycles that rely on water brought to <a href="https://theconversation.com/hidden-housemates-the-mosquitoes-that-battle-for-our-backyards-59072">wetlands, flood plains, and water-holding containers</a> by seasonal rainfall. Depending on whether we’re experiencing a summer under the influence of <a href="https://theconversation.com/will-the-arrival-of-el-nino-mean-fewer-mosquitoes-this-summer-102496">El Niño</a> or <a href="https://theconversation.com/la-nina-will-give-us-a-wet-summer-thats-great-weather-for-mozzies-147180">La Niña</a>, mosquito populations will change in different ways.</p>
<p>During warmer months, their life cycle lasts about a month. Eggs laid around water hatch and the immature mosquitoes go through four developmental stages. Larvae then change to pupae, from which an adult mosquito emerges, sits briefly on the water surface, and then flies off to buzz and bite and continue the cycle. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/the-worst-year-for-mosquitoes-ever-heres-how-we-find-out-68433">The worst year for mosquitoes ever? Here's how we find out</a>
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<p>Water is crucial but temperature is really important too. Unlike warm-blooded animals, mosquitoes can’t control their own body temperatures. The warmer it is, the more active mosquitoes will be. There’s usually more of them about too.</p>
<p>But once cold weather arrives, their activity slows. They fly less, they don’t bite as often, they reproduce less, and their life cycle takes longer to complete.</p>
<p>Temperature also plays a role in determining the ability of mosquitoes to <a href="https://www.frontiersin.org/articles/10.3389/fmicb.2020.584846/full">spread viruses</a>.</p>
<p>Cold weather isn’t great for mosquitoes but <a href="https://www.annualreviews.org/doi/abs/10.1146/annurev-ento-011613-162023">millions of years of evolution</a> have given them a <a href="https://link.springer.com/article/10.1186/s13071-017-2235-0">few tricks to survive</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/468677/original/file-20220614-21-qmcj4w.jpg?ixlib=rb-1.1.0&rect=0%2C43%2C4883%2C3211&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/468677/original/file-20220614-21-qmcj4w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/468677/original/file-20220614-21-qmcj4w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/468677/original/file-20220614-21-qmcj4w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/468677/original/file-20220614-21-qmcj4w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/468677/original/file-20220614-21-qmcj4w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/468677/original/file-20220614-21-qmcj4w.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">Ponds and puddles may be frozen but that doesn’t mean all mosquitoes have disappeared.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/7UYnlgDyf0o">Tom Keldenich/Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Mosquitoes don’t disappear completely</h2>
<p>On a sunny afternoon in winter, you may notice the occasional mosquito buzzing about in your backyard. Not as many as in summer but they’re still around.</p>
<p>Some mosquitoes do disappear. For example, the activity of the pest mosquito <em>Culex annulirostris</em>, thought to play an important role in the <a href="https://theconversation.com/japanese-encephalitis-virus-has-been-detected-in-australian-pigs-can-mozzies-now-spread-it-to-humans-178017">spread of Japanese encephalitis virus</a> in Australia, dramatically declines when temperatures start dropping <a href="https://onlinelibrary.wiley.com/doi/10.1111/j.1442-9993.1980.tb01260.x">below 17.5°C</a>.</p>
<p><a href="https://onlinelibrary.wiley.com/doi/10.1111/aen.12021">Studies in Sydney</a> have shown some mosquitoes, such as <em>Culex annulirostris</em>, disappear. Others, such as <em>Culex quinquefasciatus</em> and <em>Culex molestus</em>, remain active throughout the winter. You just may not notice them (unless they enter your home to buzz about your ears). </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/469917/original/file-20220621-17-k6jyri.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/469917/original/file-20220621-17-k6jyri.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/469917/original/file-20220621-17-k6jyri.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/469917/original/file-20220621-17-k6jyri.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/469917/original/file-20220621-17-k6jyri.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/469917/original/file-20220621-17-k6jyri.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/469917/original/file-20220621-17-k6jyri.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">Some mosquitoes, such as the common Aedes notoscriptus, may occasionally be seen buzzing about in winter.</span>
<span class="attribution"><span class="source">Cameron Webb/NSW Health Pathology</span></span>
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<h2>Mosquitoes can disappear into diapause</h2>
<p>We’re familiar with the idea of mammals hibernating through winter but mosquitoes, like many other insects, can enter a phase of inactivity called <a href="https://onlinelibrary.wiley.com/doi/10.1111/eea.12753">diapause</a>. </p>
<p>Once cold weather arrives, adult mosquitoes find hiding places such as tree hollows and animal burrows, within the cracks and crevices of bushland environments, or in garages, basements or other structures around our homes, suburbs and cities. These mosquitoes may only live a few weeks during summer but going into diapause allows them to survive many months through winter.</p>
<p>Mosquitoes can also be found in frozen bodies of water, whether it is a bucket of water in your backyard or a near freezing wetland. For example, there is a group of mosquitoes that belong to the genus <em>Coquillettidia</em> whose <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/jvec.12338">larvae attach</a> to the submerged parts of aquatic plants and can survive the cold winter temperatures. Their development dramatically slows and they’ll stay in the water until spring arrives.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/469888/original/file-20220621-11-eny4r6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/469888/original/file-20220621-11-eny4r6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/469888/original/file-20220621-11-eny4r6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/469888/original/file-20220621-11-eny4r6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/469888/original/file-20220621-11-eny4r6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/469888/original/file-20220621-11-eny4r6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/469888/original/file-20220621-11-eny4r6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/469888/original/file-20220621-11-eny4r6.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>
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<span class="caption">By going into ‘diapause’ adults can survive in places like tree hollows for the cold months.</span>
<span class="attribution"><a class="source" href="https://images.unsplash.com/photo-1625635756778-218152037ccc?ixlib=rb-1.2.1&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&w=1770&q=80">Unsplash/Pat Whelan</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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Read more:
<a href="https://theconversation.com/how-can-the-bite-of-a-backyard-mozzie-in-australia-make-you-sick-171601">How can the bite of a backyard mozzie in Australia make you sick?</a>
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<h2>All their eggs in one winter basket</h2>
<p>Some mosquitoes make it through the winter thanks to their eggs. Mosquito eggs can be incredibly resilient. They survive being dried out in hot and salty coastal wetlands during summer but also frozen in snow-covered creeks in winter.</p>
<p>In coastal regions of Australia, eggs of the saltmarsh mosquito (<em>Aedes vigilax</em>), sit perfectly safely on soil. Once the weather warms and tides bring in water to the wetlands, these eggs will be ready to hatch.</p>
<p>There is also a special mosquito in Australia known as the “snow melt mosquito” (<em>Aedes nivalis</em>) whose <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1440-6055.1996.tb01371.x">eggs survive under snow</a> and hatch once that snow melts and fills ponds, creeks and wetlands throughout alpine regions.</p>
<h2>Does it matter where mosquitoes go in the winter?</h2>
<p>It also isn’t just the mosquitoes that survive the cold months. Viruses, such as <a href="https://theconversation.com/japanese-encephalitis-virus-can-cause-deadly-brain-swelling-but-in-less-than-1-of-cases-178985">Japanese encephalitis virus</a> or <a href="https://theconversation.com/explainer-what-is-ross-river-virus-24630">Ross River virus</a>, can survive from <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2631767/">summer to summer</a> in mosquito eggs, immature stages, or diapausing adults.</p>
<p>Knowing the seasonal spread of mosquitoes helps health authorities design surveillance and control programs. It may help understand how <a href="https://entomologytoday.org/2022/05/24/snow-covered-tires-help-invasive-mosquitoes-survive-cold-winters/">invasive mosquitoes survive</a> conditions in Australia outside their native ranges by <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0211167">hiding out from the cold</a>, such as in rainwater tanks. </p>
<p>Even mosquitoes typically found in tropical locations can even <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2664.13480">adapt to cooler climates</a>.</p>
<p>This knowledge may even expose the chilly chink in mosquito’s armour that we can use to better control mosquito populations and reduce the risks of disease outbreaks.</p><img src="https://counter.theconversation.com/content/185021/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cameron Webb and the Department of Medical Entomology, NSW Health Pathology, have been engaged by a wide range of insect repellent and insecticide manufacturers to provide testing of products and provide expert advice on mosquito biology. Cameron has also received funding from local, state and federal agencies to undertake research into mosquito-borne disease surveillance and management.</span></em></p>Mosquitoes are commonplace in summer but where do they go once the weather cools? They don’t completely disappear but find fascinating ways to survive the winter.Cameron Webb, Clinical Associate Professor and Principal Hospital Scientist, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1812312022-04-21T18:44:57Z2022-04-21T18:44:57ZClimate change is altering the seasonal rhythm of plant life-cycle events<figure><img src="https://images.theconversation.com/files/458261/original/file-20220414-12-lyqvov.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Changes in climate affect the timings of various points in the life cycle of plants, including when flowers bloom in spring and when leaves wither in autumn.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>“<em>Si sta come d’autunno sugli alberi le foglie</em>.” </p>
<p>“We are like autumn leaves on branches,” <a href="https://cultura.biografieonline.it/soldati-ungaretti/">Italian poet Giuseppe Ungaretti wrote in his 1918 poem <em>Soldati</em></a> (Soldiers), on the tragedy of human life and war.</p>
<p>If the popular image of autumn is <a href="https://doi.org/10.1177%2F039219216201003804">decadence and nostalgia</a> after the summer heat, spring is the season of rebirth after the darkness and cold of winter. The transformative passing of seasons has historically represented a powerful mental image, rich in symbolism. The seasonal timings of biological events are also an essential aspect of <a href="https://doi.org/10.1016/j.tree.2007.04.003">plant adaptation</a> and can also be of crucial <a href="https://doi.org/10.1007/978-90-481-3335-2_4">economic relevance</a>. </p>
<p>However, as forest ecologists, we have observed that climate change has been modifying the timing of recurrent plant life-cycle events, thus critically affecting the ecosystem. </p>
<h2>The plant’s clock</h2>
<p>In spring, flowers bloom. In summer, fruits ripen. In autumn, leaves change colour and fall. In winter, plants rest. This is <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/phenology">phenology</a> — the study of the timing of recurring life-cycle events. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/W0jjyf7sRY8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The life-cycle of plants, animals and all life forms depends on the environment around them.</span></figcaption>
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<p>So how do plants recognize the passage of time and the right moment to accomplish growth and reproduction? Like people, plants have their own calendar. A plant’s clock is represented by cycles in the environmental conditions, and the timing of phenological events is <a href="https://doi.org/10.1111/gcb.14619">controlled by climate</a>. </p>
<p>Specifically, plants use a set of triggers to synchronize the timings of growth and reproduction with favourable environmental conditions. </p>
<p>Depending on the species, phenological events are triggered by temperature (autumn and winter chilling and spring warming), photoperiod (length of day), precipitation or, often, a combination of these.</p>
<h2>If climate changes, phenology changes</h2>
<p>Phenology is one of the most sensitive biological indicators of the changing climate. Under the progressive rise in temperature experienced in the last century and the variations in seasonal distribution of rainfall events, the <a href="https://doi.org/10.1111/gcb.14619">environmental triggers usually occur earlier and earlier</a>. </p>
<p>This is why phenological shifts have been observed worldwide, and contextually, it seems that phenological events are occuring earlier year by year. </p>
<p>Japan’s <em>Sakura</em> or cherry blossom season is one of the <a href="https://doi.org/10.1007/s00484-019-01719-9">most evident proofs</a> of this shift. Dating back to the ninth century, the date of flowering, which defines the festival’s timing, has been anticipated in the last century by the rise in average temperatures. </p>
<h2>What is the problem? Spring is cool, right?</h2>
<p>American poet <a href="https://www.goodreads.com/quotes/136895-if-we-had-no-winter-the-spring-would-not-be">Anne Bradstreet</a> said, “If we had no winter, the spring would not be so pleasant.” While this is hyperbolic, we still need to consider that the timings of flowers blooming, fruits ripening and other such phenological events result from a long-lasting adaptation of each species to its surrounding environment.</p>
<figure class="align-center ">
<img alt="A lone green plant in a barren land stretch with dried plants." src="https://images.theconversation.com/files/458682/original/file-20220419-18-z0vdiu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/458682/original/file-20220419-18-z0vdiu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/458682/original/file-20220419-18-z0vdiu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/458682/original/file-20220419-18-z0vdiu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/458682/original/file-20220419-18-z0vdiu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/458682/original/file-20220419-18-z0vdiu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/458682/original/file-20220419-18-z0vdiu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=425&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Changes in the environment can have economic consequences as it affects the quantity and quality of agriculture and forestry products.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>The timing of phenological events are calibrated to ensure the perfect environmental condition needed to accomplish the annual cycles of a plant’s life while <a href="https://doi.org/10.1016/j.foreco.2020.118483">minimizing the risk of damage</a>. Changes in these conditions can have ecological as well as economic consequences as they can affect the quantity and quality of agriculture and forestry products. </p>
<p>At the end of the growing season, plants develop dormant buds to protect the sensitive <a href="https://www.britannica.com/science/meristem">meristematic cell layer</a> — tissue in which cells maintain the ability to divide throughout the life of the plant — and suspend activity. Dormancy is an adaptation mechanism evolved in climates with seasons to escape harsh winter conditions. </p>
<p>Warm spring temperatures (called forcing), the increase in day length during spring (photoperiod), and the length and intensity of winter temperatures (<a href="https://doi.org/10.1098/rstb.2011.0186">chilling</a>) reactivate the growth of the <a href="https://www.biologyonline.com/dictionary/apical-bud">apical buds</a> — the buds located at the top of the plant — in the spring. Clearly, temperature has a central and leading role in this process. For this reason, warming can trigger an <a href="https://doi.org/10.1093/treephys/tpaa096">earlier reactivation in spring</a> and a delayed cessation in autumn, or both, <a href="https://doi.org/10.1016/j.foreco.2019.01.005">lengthening the growing season</a>.</p>
<p>Some believe that a longer growing season could enhance carbon uptake and, therefore, the productivity of forests. In some places, such as regions in the northern latitudes or elevated altitudes, trees have profited from a <a href="https://doi.org/10.1016/j.foreco.2020.118483">longer growing season</a> and, more generally, more favourable climatic conditions under global warming. </p>
<figure class="align-center ">
<img alt="Snow and ice cover on a blooming cherry tree." src="https://images.theconversation.com/files/458260/original/file-20220414-26-5wo0gn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/458260/original/file-20220414-26-5wo0gn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/458260/original/file-20220414-26-5wo0gn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/458260/original/file-20220414-26-5wo0gn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/458260/original/file-20220414-26-5wo0gn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/458260/original/file-20220414-26-5wo0gn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/458260/original/file-20220414-26-5wo0gn.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">Late frosts in spring and early frosts in autumn, that often accompany longer growing seasons, increase the risk for damage to plants and trees.</span>
<span class="attribution"><span class="source">(AP Photo/Carolyn Kaster)</span></span>
</figcaption>
</figure>
<p>However, an earlier growth reactivation increases the risk of damage due to <a href="https://doi.org/10.1016/j.foreco.2019.01.005">late spring frosts, and lengthening of the growing season increases the risk of damage by early autumn frosts</a>. </p>
<p>If trees cannot adapt, or re-adapt, their phenology with the new climatic conditions, the fitness and growth performance of local populations could be dramatically affected.</p>
<h2>If phenology changes, species interaction changes</h2>
<p>Ecosystems are generally complex and the species within them interact with each other as well as their surrounding environment. Different species can react differently to the changing climatic conditions, potentially leading to dangerous new phenological matches or mismatches. </p>
<p>For example, current climatic conditions create new phenological matches between prey and predators. <a href="https://doi.org/10.1111/gcb.14991">Black spruce may become a key host for the spruce budworm</a> given that the timing of maximum larvae activity could be better synchonized with the timing of yearly shoots development, which increases the risk of severe defoliations for one of the most profitable boreal species in North America. </p>
<p>Climate change can also cause mismatches between plants and their pollinators. Bumblebees represent one of the <a href="https://doi.org/10.1126/science.aaa7031">most important pollinators</a> for several wild species and many varieties of enormous agricultural interest. Bumblebees, given their low heat and cold tolerance, are particularly sensitive to environmental conditions. For this reason, the projected climatic risk for this species is <a href="https://doi.org/10.1126/science.aaa7031">extremely high</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/458284/original/file-20220414-14135-yes4wi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A bumblebee sits on a wild flower." src="https://images.theconversation.com/files/458284/original/file-20220414-14135-yes4wi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/458284/original/file-20220414-14135-yes4wi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=516&fit=crop&dpr=1 600w, https://images.theconversation.com/files/458284/original/file-20220414-14135-yes4wi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=516&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/458284/original/file-20220414-14135-yes4wi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=516&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/458284/original/file-20220414-14135-yes4wi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=648&fit=crop&dpr=1 754w, https://images.theconversation.com/files/458284/original/file-20220414-14135-yes4wi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=648&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/458284/original/file-20220414-14135-yes4wi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=648&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Bumblebees are extremely sensitive to climate change.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>The mutually beneficial plant-pollinator relationship is an essential ecosystem service, specially considering that the pollination done by insects contributes to <a href="https://doi.org/10.1016/j.ecolecon.2008.06.014">9.5 per cent of global food production</a>.</p>
<h2>Action must be taken</h2>
<p>As the climate continues to change, affecting all kinds of ecosystems in the process, we need to be aware of plant phenology and think about how these shifts may directly affect our lives and businesses. </p>
<p>Scientists, today, use observational data to determine how species, populations and communities are vulnerable to these ongoing and projected future changes in climate. This research can be the foundation for essential human intervention, which may influence <a href="https://doi.org/10.1016/j.foreco.2019.01.005">plant distribution through assisted migration</a>, which is the human-assisted movement of species to areas far outside their established range. This will help tree species resynchronize their phenology to the current climatic condition. </p>
<p>Plant phenology is the result of an adaptation. However, adaptation requires time, an amount of time we do not have given the magnitude and rate at which we are observing climate changes. Constantly monitoring the phenological shifts worldwide will allow us to develop sound strategies to protect the most vulnerable ecosystems as well as our businesses. </p>
<p>Besides, we are like autumn leaves on branches, but at least we should try not to fall!</p><img src="https://counter.theconversation.com/content/181231/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Roberto Silvestro received the Merit scholarship for international PhD students (PBEEE) assigned by the Fonds de Recherche du Québec - Nature et Technologies (FRQNT). </span></em></p><p class="fine-print"><em><span>Sergio Rossi receives funding from Natural Sciences and Engineering Research Council of Canada, Fonds de recherche du Québec - Nature et technologie, Ministère des Forêts, de la Faune et des Parcs du Québec</span></em></p>Climate change is modifying the timing of recurrent life-cycle events with critical consequences on ecological and economic levels.Roberto Silvestro, PhD candidate, biology, Université du Québec à Chicoutimi (UQAC)Sergio Rossi, Professor, Département des Sciences Fondamentales, Université du Québec à Chicoutimi (UQAC)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1629062021-06-23T15:43:17Z2021-06-23T15:43:17ZIt’s time to have a serious conversation about the future of Canadian football<figure><img src="https://images.theconversation.com/files/407974/original/file-20210623-23-r6nd8.jpg?ixlib=rb-1.1.0&rect=6%2C26%2C4471%2C3055&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The future of the Canadian Football League is in doubt as it resumes play for the first time since 2019.</span> <span class="attribution"><span class="source">THE CANADIAN PRESS/John Woods </span></span></figcaption></figure><p>The urgent human and social toll of COVID-19 has rightly consumed the attention of our country for the past 15 months. </p>
<p>But a story that has been overlooked is the profound impact on community institutions. Thousands of educational, arts, sports and recreation organisations have not survived the pandemic, while others are still teetering. </p>
<p>One of the institutions at risk is <a href="https://www.cbc.ca/radio/costofliving/re-recording-musical-masters-and-the-future-of-canadian-football-1.6032829/can-the-cfl-survive-covid-19-or-is-canadian-football-being-forced-into-a-fourth-down-1.6032846">the Canadian Football League</a>. A serious national conversation about its future is urgently required.</p>
<h2>The prominence of the CFL</h2>
<p>The history and scope of the CFL is unique in Canada. Its roots go back to the 1860s with the <a href="https://web.archive.org/web/20070228064050/http:/www.footballcanada.com/history_timeline.asp">first game being played at the University of Toronto</a> and its evolution is tied to <a href="https://3downnation.com/2020/07/12/early-history-of-the-canadian-football-league/">Canadian rugby</a>. The first Grey Cup was <a href="https://cfhof.ca/history-of-the-grey-cup/">awarded in 1909</a>. With over <a href="https://www.cfl.ca/game-rule-ratio/">50 per cent of the players required to be Canadian</a>, it was the first — and remains one of the only — institution that embeds Canadian content as core to its business model. </p>
<p>The role of Canadians playing a Canadian game in Canada clearly has appeal because in 2019, almost four million tickets were sold to CFL games. Many may be surprised that in North America, CFL game day attendance is <a href="https://3downnation.com/2021/03/21/the-cfls-business-model-isnt-broken-its-leadership-has-failed/">only exceeded by</a> the National Football League and Major League Baseball. </p>
<p>For most CFL cities that have both National Hockey League and CFL teams, the CFL team’s season ticket-holder base <a href="https://www.hockeydb.com/nhl-attendance/">dwarfs its NHL counterparts</a>. And <a href="https://www.tsn.ca/107th-grey-cup-presented-by-shaw-audience-grows-19-to-3-9-million-viewers-on-tsn-and-rds-1.1403625">one-third</a> of Canadians tuned in to watch the last Grey Cup.</p>
<p>For all these reasons, no other institution in the country comes close to rivalling the CFL’s historic and cultural roots.</p>
<figure class="align-center ">
<img alt="Archive photo of Jack Maynard kicking the winning field goal at the grey cup in 1910" src="https://images.theconversation.com/files/406842/original/file-20210616-3629-87eeee.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/406842/original/file-20210616-3629-87eeee.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=349&fit=crop&dpr=1 600w, https://images.theconversation.com/files/406842/original/file-20210616-3629-87eeee.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=349&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/406842/original/file-20210616-3629-87eeee.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=349&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/406842/original/file-20210616-3629-87eeee.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=438&fit=crop&dpr=1 754w, https://images.theconversation.com/files/406842/original/file-20210616-3629-87eeee.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=438&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/406842/original/file-20210616-3629-87eeee.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=438&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Jack Maynard kicks the winning field goal for the Rugby Football Dominion Championship (also known as the Grey Cup) in 1910.</span>
<span class="attribution"><span class="source">(University of Toronto Archives/A1973-0026/315(58)0001)</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>A gate-driven league</h2>
<p>The difficulty is that unlike many of the larger professional sports leagues, the CFL is a league dependent on having paying fans in the stadium. </p>
<p>A <a href="https://www.washingtonpost.com/sports/2020/05/08/unlike-other-leagues-cfl-needs-fans-stands-survive-coronavirus-pandemic/">majority</a> of CFL revenues are tied to game day sources (tickets, parking, concessions). In comparison, only <a href="https://www.washingtonpost.com/sports/2020/05/08/unlike-other-leagues-cfl-needs-fans-stands-survive-coronavirus-pandemic/">18 per cent</a> of the revenue from the NFL’s Washington franchise comes from game day. </p>
<p>CFL teams are small, mostly locally owned businesses. As a result, few were surprised that the CFL was one of the only professional leagues forced to <a href="https://www.tsn.ca/cfl-cancels-2020-season-1.1510345">cancel its entire 2020 season</a>. With no revenues, the league lost <a href="https://3downnation.com/2021/02/18/cfl-lost-between-60-and-80-million-through-cancelled-2020-season-report/">an estimated combined $60-80 million</a>. Even with the recent announcement that the league intends to proceed with a 14-game season this summer, serious questions remain about its future. </p>
<p>In looking for a path forward, the CFL is considering the ultimate <em>hail mary pass</em>: The XFL. </p>
<h2>Is the XFL a solution to the CFL’s problems?</h2>
<p>The XFL is a United States-based football league and, like every attempt to establish a competitor to the NFL since the 1970s, has been an unquestionable failure.</p>
<p>The XFL’s first iteration lasted one season. It was best summed up by broadcaster Bob Costas, who characterized it as <a href="https://www.nhregister.com/news/article/Notes-amp-Quotes-The-lighter-side-of-sports-11723990.php">a combination of high school football and a strip club</a>. The XFL tried again in 2020 and lasted five games before <a href="https://www.espn.com/xfl/story/_/id/29030763/xfl-files-chapter-11-bankruptcy-suspending-operations">declaring bankruptcy during the pandemic</a>. </p>
<p>In August, the remains of the defunct XFL were <a href="https://www.latimes.com/sports/story/2020-08-03/dwayne-johnson-buys-xfl-the-rock">purchased for $15 million by a consortium</a> led by professional wrestler and movie star Dwayne (The Rock) Johnson. The assets of the entire XFL were valued at less than 10 per cent of the CFL’s revenue. </p>
<p>In early March, the CFL and XFL announced that they were <a href="https://www.cbc.ca/sports/football/cfl/cfl-xfl-in-discussions-potential-partnership-1.5943958">discussing a potential partnership</a>. What exactly does this mean? No one knows. </p>
<p>With nondisclosure agreements signed by both the CFL and XFL, the lack of community engagement is deafening.</p>
<p>This type of backroom negotiating reflects a perception that some CFL owners and administrators view these historic community assets as their assets. A similar approach was seen earlier this year with the debacle called the <a href="https://www.cnn.com/2021/04/24/football/super-league-how-it-unraveled-cmd-spt-intl/index.html">European Super League</a>. This backroom deal, that would tear apart the historic roots of European soccer, lasted less than 48 hours and collapsed after enormous community backlash. </p>
<figure class="align-center ">
<img alt="Winnipeg Blue Bombers football player holds up grey cup as confetti rains down" src="https://images.theconversation.com/files/407099/original/file-20210617-12-h30vwf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/407099/original/file-20210617-12-h30vwf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/407099/original/file-20210617-12-h30vwf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/407099/original/file-20210617-12-h30vwf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/407099/original/file-20210617-12-h30vwf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/407099/original/file-20210617-12-h30vwf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/407099/original/file-20210617-12-h30vwf.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 last Grey Cup broadcast was watched by one-third of Canadian households.</span>
<span class="attribution"><span class="source">THE CANADIAN PRESS/Frank Gunn</span></span>
</figcaption>
</figure>
<p>CFL owners and senior administration must recognize they are not only owners, they are also caretakers of an historic institution. </p>
<p>With this role comes responsibility to be open and engage their communities in a real conversation. With no public engagement, the CFL has so far shirked that responsibility.</p>
<h2>Where from here?</h2>
<p>This XFL <em>hail mary</em> was triggered solely by the pandemic. Today, many owners would argue they are pursuing this partnership to save, not destroy the legacy of the CFL.</p>
<p>However, anyone who understands negotiations, understands the importance of having core principles, supported by a range of viable <a href="https://hbr.org/2020/07/whats-your-negotiation-strategy">strategic options</a>. These options provide the essential strength to not compromise one’s principles. </p>
<p>It is imperative that the federal and provincial governments engage because these negotiations are not about football, they are about a historic institution whose roots date to Confederation. </p>
<p>Governments in Canada have long backstopped organizations from <a href="https://www.theglobeandmail.com/report-on-business/canadian-taxpayers-lose-35-billion-on-2009-bailout-of-auto-firms/article23828543/">General Motors</a> and <a href="https://www.newswire.ca/news-releases/bombardier-over-4-billion-in-public-funds-since-1966-613177623.html">Bombardier</a>, to <a href="https://www.cbc.ca/news/politics/air-canada-financial-relief-1.5984543">Air Canada</a> and <a href="https://www.cbc.ca/news/entertainment/quebec-govt-cirque-soleil-support-covid-coronavirus-1.5585509">Cirque du Soleil</a> deemed too big to fail. As a historic institution, the CFL is too important to fail or sell out to simply survive.</p>
<figure class="align-center ">
<img alt="Football player stands in empty stadium" src="https://images.theconversation.com/files/407106/original/file-20210617-14657-164nks4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/407106/original/file-20210617-14657-164nks4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/407106/original/file-20210617-14657-164nks4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/407106/original/file-20210617-14657-164nks4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/407106/original/file-20210617-14657-164nks4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=473&fit=crop&dpr=1 754w, https://images.theconversation.com/files/407106/original/file-20210617-14657-164nks4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=473&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/407106/original/file-20210617-14657-164nks4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=473&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The pandemic was really hard on the CFL.</span>
<span class="attribution"><span class="source">THE CANADIAN PRESS/Todd Korol</span></span>
</figcaption>
</figure>
<p>Interest-free bridge loans from governments would give the league the stability to explore a variety of post-pandemic business models, one being the XFL. This government backstop should also come with conditions. </p>
<p>The first that CFL owners and senior administration must assume their role as caretakers. This would involve being transparent and engaging their communities as real partners. The second condition is that there are core characteristics, such as Canadian content and unique rules, that make the CFL a historic cultural institution and these principles cannot be traded away for a quick cash infusion. </p>
<p>The impacts of the pandemic on our communities and country will be felt for generations. Now is the time to reflect on what is irreplaceable. </p>
<p>The history and culture embodied in the CFL cannot be replaced. The time is now for the league to step up to engage their communities and the nation in an important conversation. The decisions they will make are about far more than football.</p><img src="https://counter.theconversation.com/content/162906/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David J Finch has previously conducted research for Calgary Sports and Entertainment Corporation. </span></em></p>The Canadian Football League is struggling to stay alive. All options, including help from government, should be considered as part of a national conversation about its future.David J Finch, Professor and Associate Director, Institute for Community Prosperity, Mount Royal UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1612992021-05-21T15:32:06Z2021-05-21T15:32:06ZEurope has had a cold and wet spring – but will it last through summer?<p>Spring has not yet arrived in much of western Europe. It has been particularly miserable in Britain, which recorded the <a href="https://www.metoffice.gov.uk/about-us/press-office/news/weather-and-climate/2021/lowest-average-minimum-temperatures-since-1922-as-part-of-dry-april">coldest April in a century</a> and is experiencing an unusually <a href="https://www.independent.co.uk/weather/uk-weather-forecast-may-rainfall-b1850058.html">wet May</a>. </p>
<p>In the Netherlands, where I live, rain has been pouring down for weeks. We also had the coldest April in decades, which included <a href="https://nltimes.nl/2021/05/01/coldest-april-35-years-brought-mix-sun-snow-hail-frost">more snow</a> than any year since 1977. Most of western Europe has suffered a <a href="https://www.washingtonpost.com/weather/2021/05/05/europe-cold-april-2021/">cold streak</a> with the sun hiding behind thunderclouds and <a href="https://www.itv.com/news/london/2021-05-18/what-a-washout-huge-hailstorm-hits-parts-of-london">hailstorms</a>. </p>
<p>So will it get any better or is the summer of 2021 doomed?</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1394670843062595588"}"></div></p>
<p>The best models we have can only predict the weather accurately up to two weeks in advance. The further ahead we go, the more unreliable these forecasts get, and the more uncertain these predictions become. That said, the <a href="https://www.ecmwf.int">European Centre for Medium-Range Weather Forecasts</a> makes weather forecasts that go out for more than half a year.</p>
<p>Surely we cannot trust weather forecast for six months ahead, right?</p>
<p>This is not entirely true – while you shouldn’t base your bike rides and hiking adventures on these forecasts, we can definitely use them to do some long-term planning. For example, water managers can plan their operations based on the long-term estimates of precipitation and temperature to anticipate upcoming droughts, and farmers can adjust their crops to the most likely summer conditions. </p>
<p>These seasonal forecasts can give us information on whether a season is going to be wet, dry, or “normal”, as well as warm or cold compared to normal conditions. Scientists can do a pretty good job at forecasting these seasonal anomalies, but the further we go in time the <a href="https://journals.ametsoc.org/doi/full/10.1175/JHM-D-18-0040.1">more unpredictable it gets</a>. Seasonal forecasts are not able to predict the rain on any given day some three months in advance.</p>
<p>Unfortunately, western Europe is one of the hardest places in the world to predict long-term weather. This is because the region’s weather is largely driven by erratic currents of air moving over the Atlantic and doesn’t show long-term persistent patterns. As such, Europe is more difficult to predict than regions like California or South America where the weather is partly driven by anomalies in the more stable weather patterns of the Pacific Ocean.</p>
<p>To identify the “skill” or usefulness of such a seasonal weather model, scientists look at historic predictions and compare these with the current observations. Just like I could make a prediction of the weather for next week, and next week we will check whether I was wrong or right. If we do this for a long period of time, we can see whether these models work and if they have any predictive skill.</p>
<p>In this way, scientists have shown that seasonal weather models are poor at <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4032526/">predicting rain</a>, whereas the temperature predictions provide more useful information and display <a href="https://journals.ametsoc.org/view/journals/hydr/20/1/jhm-d-18-0040_1.xml">more forecast skill</a>. This means that in most cases the models make the correct prediction for summer temperatures.</p>
<p>So now the big question, what does this mean for summer 2021?</p>
<p>The models predict <a href="https://apps.ecmwf.int/webapps/opencharts/products/seasonal_system5_standard_2mtm?amp%3Bbase_time=202105010000&%3Bstats=tsum&%3Bvalid_time=202107020000&area=EURO&base_time=202105010000&stats=tsum&valid_time=202107020000">normal to warm temperatures</a> and that it will be slightly drier than usual. Southern Europe especially has a high chance of above-normal temperatures (meaning above the long-term average of 1990-2020), while Britain and northern Europe should have normal temperatures, but drier conditions. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/401911/original/file-20210520-13-1tnh3n9.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map of Europe, mostly shaded red" src="https://images.theconversation.com/files/401911/original/file-20210520-13-1tnh3n9.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/401911/original/file-20210520-13-1tnh3n9.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=412&fit=crop&dpr=1 600w, https://images.theconversation.com/files/401911/original/file-20210520-13-1tnh3n9.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=412&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/401911/original/file-20210520-13-1tnh3n9.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=412&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/401911/original/file-20210520-13-1tnh3n9.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=517&fit=crop&dpr=1 754w, https://images.theconversation.com/files/401911/original/file-20210520-13-1tnh3n9.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=517&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/401911/original/file-20210520-13-1tnh3n9.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=517&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 European Centre for Medium-Range Weather Forecasts predicts July 2021 will be warmer than usual across Europe (but not the southern tip of Portugal)</span>
<span class="attribution"><a class="source" href="https://apps.ecmwf.int/webapps/opencharts/products/seasonal_system5_standard_2mtm?amp%3Bbase_time=202105010000&amp%3Bstats=tsum&amp%3Bvalid_time=202107020000&area=EURO&base_time=202105010000&stats=tsum&valid_time=202107020000">ECMWF</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>If summer is warmer than normal it won’t really be thanks to the cold wet spring, since weather patterns don’t persist for long enough. Instead, the forecast warm weather is part of a large trend of warmer summers and <a href="https://www.nature.com/articles/s41558-018-0138-5">more droughts</a> thanks to climate change. </p>
<p>So since the world is warming, on average most forecasts will predict normal to warm summers. If you need to make an educated guess, this would be the best choice.</p>
<p>Seasonal forecasts definitely provide an added value, if you know how to use them. But we need to be aware of their limitations and see them as a general prediction or sense of direction. We expect the summer to be normal to warm, but this is just an increased chance given the information we now have based on the current conditions and forecast – any one prediction can of course still be wrong. After all, often nothing is as unpredictable as the weather.</p><img src="https://counter.theconversation.com/content/161299/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Niko Wanders 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>This summer is likely to be hot and dry, but that’s more down to climate change than miserable spring.Niko Wanders, Assistant Professor, Hydrological Extremes, Utrecht UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1573192021-04-07T20:16:58Z2021-04-07T20:16:58ZFrom fireballs in the sky to a shark in the stars: the astronomical artistry of Segar Passi<figure><img src="https://images.theconversation.com/files/391857/original/file-20210325-23-1eul34r.jpg?ixlib=rb-1.1.0&rect=0%2C168%2C1842%2C1266&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Elsie Passi</span>, <span class="license">Author provided</span></span></figcaption></figure><p>When Uncle Segar Passi watches the position of the setting Sun from his front patio, he notes its location and relates that to the time of year and changes in seasonal cycles.</p>
<p>What he sees translates into his artworks. They are visually stunning, a rich tapestry of colours jumping off the frame with a palate that easily rivals Vincent van Gogh. This is reflected in the many awards he has garnered over the years.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/392451/original/file-20210330-19-j399ei.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Lidlid, a painting of clouds across the sea, by Segar Passi" src="https://images.theconversation.com/files/392451/original/file-20210330-19-j399ei.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/392451/original/file-20210330-19-j399ei.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=386&fit=crop&dpr=1 600w, https://images.theconversation.com/files/392451/original/file-20210330-19-j399ei.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=386&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/392451/original/file-20210330-19-j399ei.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=386&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/392451/original/file-20210330-19-j399ei.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=485&fit=crop&dpr=1 754w, https://images.theconversation.com/files/392451/original/file-20210330-19-j399ei.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=485&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/392451/original/file-20210330-19-j399ei.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=485&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Lidlid by Segar Passi (2011)</span>
<span class="attribution"><span class="source">Queensland Art Gallery</span></span>
</figcaption>
</figure>
<p>His artistic talent is matched only by the depth of his wisdom and cultural knowledge, which he teaches through his practice.</p>
<h2>An island home</h2>
<p>Turning 79 this year, Uncle Segar is a senior Meriam elder and a Dauareb man, meaning his community is originally from Dauar, the larger of the two small islands off the coast of Mer (the other being Waier) in the eastern Torres Strait.</p>
<p>The volcanic trio of islands are collectively known as the Murray Island group, and sit at the very tip of the Great Barrier Reef.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/391348/original/file-20210324-23-1jo9dlv.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Mer islands" src="https://images.theconversation.com/files/391348/original/file-20210324-23-1jo9dlv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/391348/original/file-20210324-23-1jo9dlv.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=332&fit=crop&dpr=1 600w, https://images.theconversation.com/files/391348/original/file-20210324-23-1jo9dlv.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=332&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/391348/original/file-20210324-23-1jo9dlv.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=332&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/391348/original/file-20210324-23-1jo9dlv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=417&fit=crop&dpr=1 754w, https://images.theconversation.com/files/391348/original/file-20210324-23-1jo9dlv.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=417&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/391348/original/file-20210324-23-1jo9dlv.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=417&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 Murray Island group in the eastern Torres Strait: Mer (foreground), Dauar (upper right) and Waier (upper left).</span>
<span class="attribution"><span class="source">Duane Hamacher</span></span>
</figcaption>
</figure>
<p>Professor <a href="https://research.jcu.edu.au/portfolio/martin.nakata">Martin Nakata</a>, a Torres Strait Islander and Pro-Vice Chancellor at James Cook University, brought me to Mer years ago to help the community document its star knowledge for education and community programs.</p>
<p>We stood on the beach near Uncle Segar’s house, watching the sunset near the double-hilled island of Dauar when he told me:</p>
<blockquote>
<p>That place has powerful magic. If you want to learn about traditional star knowledge, you ask those elders. They’re the big dogs.</p>
</blockquote>
<p>Looking to the artworks on the wall in Uncle Segar’s workshop, I noticed a plethora of subtle characteristics encoded within each one.</p>
<p>I know his artistic style is unique and aesthetically gorgeous, but I also know that every colour, brushstroke, motif and design has meaning. I see a painting showing a crescent Moon with the cusps pointing up. Above it are puffy cumulus clouds and the moonlight reflected in the choppy waters.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/391347/original/file-20210324-15-1i4f2j4.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Crescent Moon paintings" src="https://images.theconversation.com/files/391347/original/file-20210324-15-1i4f2j4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/391347/original/file-20210324-15-1i4f2j4.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=190&fit=crop&dpr=1 600w, https://images.theconversation.com/files/391347/original/file-20210324-15-1i4f2j4.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=190&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/391347/original/file-20210324-15-1i4f2j4.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=190&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/391347/original/file-20210324-15-1i4f2j4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=239&fit=crop&dpr=1 754w, https://images.theconversation.com/files/391347/original/file-20210324-15-1i4f2j4.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=239&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/391347/original/file-20210324-15-1i4f2j4.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=239&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Kerkar Meb I (Left) and II (right), 2011. These paintings by Segar Passi show the changing orientation of the crescent Moon, which informs seasonal weather patterns.</span>
<span class="attribution"><span class="source">Segar Passi. QAGOMA, Brisbane.</span></span>
</figcaption>
</figure>
<p>Another painting, which looks nearly identical from a distance, shows the Moon tilted at an angle. The clouds above are cirrus, and the reflection of moonlight is clear and strong on the calm, still water. </p>
<p>In his characteristic soft voice, Uncle Segar explained the meaning behind this pair of paintings. </p>
<blockquote>
<p>Every month there is a New Moon at a different angle. Did you ever notice this?</p>
</blockquote>
<p>He explained how the New Moon (<em>kerker meb</em>) can tell you about the changing seasons if you look at the angle of its tilt. When the <a href="https://collection-online-beta.qagoma.qld.gov.au/objects/14159/">cusps are pointing up</a> (<em>Meb metalug em</em>), it is the dry season, the <em>Sager</em>.</p>
<p>You will see large cumulus clouds in the evening sky and the water is choppy. When the <a href="https://collection-online-beta.qagoma.qld.gov.au/objects/14157/">cusps point at an angle</a> (<em>Meb uag em</em>), the water is calm and you see cirrus clouds. This is the wet monsoon season, the <em>Kuki</em>. He pointed to the painting:</p>
<blockquote>
<p>If the water looks rough and the Moon is pointed up, you know the winds will die down and the next day the water will be fine.</p>
</blockquote>
<h2>The art of knowledge</h2>
<p>The paintings are a medium through which complex systems of knowledge are passed down. These systems are based on generations of collective observation, deduction and interconnection – a longstanding system of science.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-moon-plays-an-important-role-in-indigenous-culture-and-helped-win-a-battle-over-sea-rights-119081">The Moon plays an important role in Indigenous culture and helped win a battle over sea rights</a>
</strong>
</em>
</p>
<hr>
<p>Uncle Segar is an expert on clouds and weather, the plants and animals, the sea, land, and the sky. His knowledge is as deep as his artworks are captivating. </p>
<p>The self-taught artist developed his style in the 1960s and has since won several major awards for his work, gaining an international profile through his raw talent, complex works and lovely personality. But his passion is for local community, both on Mer and across the Torres Strait.</p>
<p>Uncle Segar’s work has appeared in local school books and seasonal calendars about <a href="https://www.indigenous.gov.au/news-and-media/announcements/meriam-community-and-tsra-collaborate-help-preserve-meriam-language-and">traditional knowledge</a>. He has also worked closely with me and other academics over the years, sharing Meriam Star Knowledge and co-authoring several research papers.</p>
<p>These include publications about traditional ways of interpreting <a href="https://arxiv.org/abs/1903.01060" title="Indigenous use of stellar scintillation to predict weather and seasonal change">the twinkling stars</a>, the role of <a href="https://arxiv.org/abs/1605.08507" title="Dancing with the stars - astronomy and music in the Torres Strait">astronomy in song and dance</a>, and the relationship between <a href="https://arxiv.org/abs/1810.11276" title="Death and Maier: meteors and mortuary rites in the eastern Torres Strait (Eud kerker: na korep maierira asmer opged Torres Straitge)">bright meteors and death rites</a> in the Torres Strait.</p>
<p>Uncle Segar is currently contributing to a major book on Indigenous astronomy for a global audience and has been featured in recent Indigenous astronomy articles in <a href="https://cosmosmagazine.com/space/astronomy/learning-the-star-knowledge-of-first-australians/">Cosmos magazine</a>. His knowledge has even been written into the <a href="https://indigenousknowledge.unimelb.edu.au/curriculum/resources/law,-song,-and-a-meriam-moon-dance">Australian National Curriculum</a> for schools across the country.</p>
<h2>The flying spirits</h2>
<p>This knowledge has found its way into films by some of the world’s most critically acclaimed directors. Members of the Mer community performed the <em>Maier</em> (Shooting Star) dance for the 2020 Werner Herzog and Clive Oppenheimer film <a href="https://www.imdb.com/title/tt9203832/">Fireball: Visitors from Darker Worlds</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/K4X9fQsiAOQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Fireball, Visitors from Darker Worlds.</span></figcaption>
</figure>
<p><em>Maier</em> is a term from the Meriam Mir language referring to fireballs (exceptionally bright meteors), which are seen as a celestial personification of a recently deceased person’s spirit flying to <em>Beig</em>, the land of the dead.</p>
<p>The brightness, trajectory and sound of a Maier all have special meaning. If the <em>Maier</em> breaks into fragments and you see sparks fall (<em>uir-uir</em>), you know that person left behind a large family.</p>
<p>The trajectory of the <em>Maier</em> tells you where that person is from. And when you hear the booming sound (<em>dum</em>) as the fireball explodes, it tells you that person has arrived at their destination.</p>
<p>The <em>Maier</em> dance is originally from Mer but had not been performed on the island since 1969. In late 2019, the community approved Herzog and Oppenheimer to film the dance on Mer.</p>
<p>Led by Meriam elder Alo Tapim, four local dancers were taught the <em>kab kar</em> (sacred dance) and performed it on the beach at sunset just hours later, with cameras rolling. The segment you see at the end of the film is the first time the dance had been performed on Mer in 50 years.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/391607/original/file-20210325-19-pzexgo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Maier Dance" src="https://images.theconversation.com/files/391607/original/file-20210325-19-pzexgo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/391607/original/file-20210325-19-pzexgo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/391607/original/file-20210325-19-pzexgo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/391607/original/file-20210325-19-pzexgo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/391607/original/file-20210325-19-pzexgo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/391607/original/file-20210325-19-pzexgo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/391607/original/file-20210325-19-pzexgo.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">A ‘Behind-the-Scenes’ photo of the community performing the Maier Dance on Mer at dusk for the film ‘Fireball’ in 2019.</span>
<span class="attribution"><span class="source">Duane Hamacher</span></span>
</figcaption>
</figure>
<h2>Name in the stars</h2>
<p>In 2020, his lifetime of work and his contributions to astronomy were recognised when the International Astronomical Union renamed the asteroid “1979 MH4” as “<a href="https://minorplanetcenter.net/db_search/show_object?object_id=7733">7733 Segarpassi</a>”.</p>
<p>This is a 1.9km-wide asteroid in the main asteroid belt between Mars and Jupiter. It is 2.4 times farther from the Sun than Earth is, and takes 3.7 years to orbit the Sun.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/from-7809-marcialangton-to-7630-yidumduma-5-asteroids-named-after-aboriginal-and-torres-strait-islander-people-144596">From 7809 Marcialangton to 7630 Yidumduma: 5 asteroids named after Aboriginal and Torres Strait Islander people</a>
</strong>
</em>
</p>
<hr>
<p>Uncle Segar’s important contributions to culture and science are also encapsulated in the newly released commemorative coin “The Shark in the Stars”.</p>
<p>Released on March 4, 2021 by the Royal Australian Mint, this non-circulating coin features Uncle Segar’s artwork. It is the third and final instalment of the Star Dreaming series, and was so popular all 5,000 coins sold out within two hours.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/390049/original/file-20210317-15-19p9ssy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Beizam, the Shark in the Stars" src="https://images.theconversation.com/files/390049/original/file-20210317-15-19p9ssy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/390049/original/file-20210317-15-19p9ssy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=460&fit=crop&dpr=1 600w, https://images.theconversation.com/files/390049/original/file-20210317-15-19p9ssy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=460&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/390049/original/file-20210317-15-19p9ssy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=460&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/390049/original/file-20210317-15-19p9ssy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=578&fit=crop&dpr=1 754w, https://images.theconversation.com/files/390049/original/file-20210317-15-19p9ssy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=578&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/390049/original/file-20210317-15-19p9ssy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=578&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Beizam, the Shark in the Stars. Uncirculated $1 coin released by the Royal Australian Mint.</span>
<span class="attribution"><span class="source">Royal Australian Mint</span></span>
</figcaption>
</figure>
<p>The celestial shark is called <em>Beizam</em>, a Meriam constellation formed by the bright stars of the Big Dipper (part of the Western constellation <a href="https://www.iau.org/public/themes/constellations/#uma"><em>Ursa Major</em>, the Big Bear</a>). It traces out the head, body, fins and tail of the shark.</p>
<p>The changing position of the shark in the northern skies throughout the year is a seasonal marker that notes shifting seasons, when to hunt turtle, when to harvest yams, and informs the observer about the behaviour of the shark itself.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/new-coins-celebrate-indigenous-astronomy-the-stars-and-the-dark-spaces-between-them-145923">New coins celebrate Indigenous astronomy, the stars, and the dark spaces between them</a>
</strong>
</em>
</p>
<hr>
<p>When the nose of Beizam touches the horizon at sunset, sharks are feeding on sardines that swim in tight ribbons close to the shore. This occurs during the Sager, which can be a dangerous time to go for a dip. </p>
<p>Later in the year, as the shark dives below the horizon at dusk, you will see the first lightning of the coming monsoon.</p>
<p>Meriam people teach that water rushes through Beizam’s gills as it dives into the sea on the horizon, casting water into the sky which falls as the rains of the wet season, the <em>Kuki</em>.</p>
<p>Uncle Segar Passi continues to share his knowledge with the world, benefiting his community and the next generation of Meriam scholars. And we are exceptionally lucky and honoured to continue learning from Elders like him.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-shark-in-the-stars-astronomy-and-culture-in-the-torres-strait-15850">A shark in the stars: astronomy and culture in the Torres Strait</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/157319/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Duane W. Hamacher worked as the consultant for the commemorative coins for the Royal Australian Mint and for the film Fireball, and worked with the IAU to rename the asteroid in honour of Uncle Segar. His work with communities in the Torres Strait was funded by an Australian Research Council DECRA Fellowship. He also receives funding from the Pierce Bequest, The Laby Foundation, the McCoy Seed Fund, and the Indigenous Knowledges Institute, all at the University of Melbourne.</span></em></p>Uncle Segar is an expert on many things including the land, sea and sky. This knowledge is then captured in his artworks.Duane Hamacher, Associate Professor, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1572732021-03-18T16:20:45Z2021-03-18T16:20:45ZDay and night aren’t equal length on an equinox – here’s why<figure><img src="https://images.theconversation.com/files/390339/original/file-20210318-23-30nzx5.jpg?ixlib=rb-1.1.0&rect=179%2C116%2C5658%2C3071&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sunset.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/sunset-on-field-706726291">Shutterstock/Delcroix Romain</a></span></figcaption></figure><p>Winter in the northern hemisphere and summer in the southern hemisphere are both coming to an end. That means the days and nights are becoming roughly equal in length, and the path the Sun traces across the sky is changing. </p>
<p>On a winter day, the Sun is low in the sky, whereas on a summer’s day the Sun lies considerably higher. But on a specific day in the spring or autumn, the Sun will be visible directly above the equator, somewhere in the middle of the two arcs traced by the Sun in the summer and winter. </p>
<p>This is what’s called the equinox, and there are two each year. Around 20 March we have the vernal equinox or March equinox, also known as the spring equinox in the northern hemisphere. Then around the 22 or 23 September is the autumnal or September equinox.</p>
<p>The word “equinox” comes from the Latin words <em>aequus</em> meaning equal and <em>nox</em> meaning night. But day and night are not exactly equal length on the equinox. To understand why, we need to know what causes the equinox in the first place.</p>
<h2>Earth’s tilt</h2>
<p>The reason we on Earth have equinoxes at all is because the Earth’s axis is tilted. The Earth spins around an imaginary line running through it called its axis. If the axis pointed straight from top to bottom, at a right angle to the direction of Earth’s orbit around the sun, the intensity of the light shining on Earth’s hemispheres would be the same all year round, and we wouldn’t have seasons. </p>
<p>Some planets in our solar system are like this – for example, Venus’ axis points nearly straight from top to bottom.</p>
<figure class="align-center ">
<img alt="A diagram showing how the Sun moves across the sky on the equinoxes and solstices." src="https://images.theconversation.com/files/390337/original/file-20210318-19-umq2p8.jpg?ixlib=rb-1.1.0&rect=150%2C176%2C5055%2C2841&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/390337/original/file-20210318-19-umq2p8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=343&fit=crop&dpr=1 600w, https://images.theconversation.com/files/390337/original/file-20210318-19-umq2p8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=343&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/390337/original/file-20210318-19-umq2p8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=343&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/390337/original/file-20210318-19-umq2p8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=431&fit=crop&dpr=1 754w, https://images.theconversation.com/files/390337/original/file-20210318-19-umq2p8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=431&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/390337/original/file-20210318-19-umq2p8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=431&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Sun throughout the year.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/earth-seasons-effect-earths-axial-tilt-1340282894">Shutterstock/Artreef</a></span>
</figcaption>
</figure>
<p>Earth is not like Venus. Instead, Earth’s axis is knocked somewhere on its side – the technical name for this is “axial tilt”, and this tilt is responsible for both the seasons and the equinox. As the Earth spins on its axis and orbits the Sun, the intensity of the sunlight reaching different parts of the Earth’s surface changes. This is why we have seasons here on Earth.</p>
<p>Earth’s axial tilt also means that our planet’s equator is tilted relative to the plane of its orbit around the Sun – what astronomers call the “plane of the ecliptic”. When the centre of the Sun’s disc perfectly crosses the equator, astronomers define this as the equinox. This happens twice a year, once in late March and once in late September.</p>
<h2>Not quite equal</h2>
<p>You might think that the lengths of the day and night would be equal during the equinox. As it turns out, this is only approximately true. The lengths of the day and night aren’t quite the same, and there are two reasons for this.</p>
<figure class="align-center ">
<img alt="An illustration of the Earth's tilt as it goes around the Sun." src="https://images.theconversation.com/files/390336/original/file-20210318-19-ymqd2f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/390336/original/file-20210318-19-ymqd2f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=424&fit=crop&dpr=1 600w, https://images.theconversation.com/files/390336/original/file-20210318-19-ymqd2f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=424&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/390336/original/file-20210318-19-ymqd2f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=424&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/390336/original/file-20210318-19-ymqd2f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=533&fit=crop&dpr=1 754w, https://images.theconversation.com/files/390336/original/file-20210318-19-ymqd2f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=533&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/390336/original/file-20210318-19-ymqd2f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=533&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Earth’s tilt.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/illustration-solstice-equinox-change-seasons-1834764796">Shutterstock/Dimitrios Karamitros</a></span>
</figcaption>
</figure>
<p>Firstly, the Sun has a size – it’s not just a point in the sky. This seems obvious, but it affects how scientists measure sunrise and sunset. Technically, sunrise starts when the upper edge of the Sun meets the eastern horizon, and sunset ends when the upper edge of the Sun sinks below the western horizon. Because the Sun is not a point, and has upper and lower edges, this means that the equinox has a slightly longer day than night.</p>
<p>Secondly, the Earth’s atmosphere refracts (bends) sunlight. When light passes from one medium to another, its path changes. Sunlight travels through the vacuum of space, and when it travels through Earth’s comparatively denser atmosphere, it bends. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/can-the-laws-of-physics-disprove-god-146638">Can the laws of physics disprove God?</a>
</strong>
</em>
</p>
<hr>
<p>This bending means that we can see the upper edge of the Sun several minutes before it touches the eastern horizon, and it also means that we can see the upper edge of the Sun several minutes after the Sun has sunk under the western horizon. This adds even more time onto daylight during the equinox. </p>
<p>What’s more, the bending changes depending on the temperature and pressure of the atmosphere, so the lengths of the night and day on the equinox are only ever approximately the same at any point on Earth.</p>
<p>There are days around the time of the equinox, where day and night are equal length. These are called equilux, and when they happens depends on latitude. In the UK in 2021, this happened on 17 March.</p><img src="https://counter.theconversation.com/content/157273/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Osnat Katz receives funding from the AHRC and the Science Museum, and her collaborative doctoral programme is with the Science Museum. </span></em></p>On the March equinox, everywhere in the world has more sunlight than darkness.Osnat Katz, PhD Candidate in Space History, UCLLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1574382021-03-18T15:46:56Z2021-03-18T15:46:56ZPasha 101: Two researchers unpack extreme temperatures in South Africa<figure><img src="https://images.theconversation.com/files/390423/original/file-20210318-13-15046sf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">shutterstock</span> </figcaption></figure><p>Extreme heat and extreme cold can both have an impact on human health. With a changing climate, these events are set to occur more often. They are also becoming increasingly difficult to predict. </p>
<p>Extreme heat stress can result in heatstroke and can affect people’s cardiovascular health. There are significant health concerns related to extreme heat events, particularly when people aren’t prepared for them. Extreme cold temperatures present a different set of challenges. For example, they can affect low income communities who live in vulnerable housing. </p>
<p>Extreme temperatures can also affect plants and animals.</p>
<p>In today’s episode of Pasha, Jennifer Fitchett, an associate professor of physical geography at the University of the Witwatersrand, and Adriaan van der Walt, a lecturer in geography at the University of the Free State, discuss their research on these extreme heat and cold events and why it’s important to try to track them.</p>
<hr>
<p><strong>Photo:</strong><br>
“Heat in South Africa concept” by <a href="https://www.shutterstock.com/image-illustration/heat-south-africa-concept-3d-rendering-1445584442">Shutterstock</a></p>
<p><strong>Music:</strong>
“Happy African Village” by John Bartmann, found on <a href="http://freemusicarchive.org/music/John_Bartmann/Public_Domain_Soundtrack_Music_Album_One/happy-african-village">FreeMusicArchive.org</a> licensed under <a href="https://creativecommons.org/publicdomain/zero/1.0/">CC0 1</a>.</p>
<p>“Ambient guitar X1 - Loop mode” by frankum, found on <a href="https://freesound.org/people/frankum/sounds/393520/">Freesound</a> licensed under <a href="http://creativecommons.org/licenses/by/3.0/">Attribution License.</a></p><img src="https://counter.theconversation.com/content/157438/count.gif" alt="The Conversation" width="1" height="1" />
Understanding when there will be extreme heat and extreme cold can help people prepare.Ozayr Patel, Digital EditorLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1520382020-12-17T10:39:27Z2020-12-17T10:39:27ZWhy snow days are becoming increasingly rare in the UK<figure><img src="https://images.theconversation.com/files/375372/original/file-20201216-19-ddxaks.jpeg?ixlib=rb-1.1.0&rect=0%2C0%2C2464%2C1630&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A snowy start to the day at Watlington station, King's Lynn. December 18 2009.</span> <span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Winter_of_2009%E2%80%9310_in_Great_Britain_and_Ireland#/media/File:Snowy_365_at_Watlington.JPG">Lewis Collard/Wikipedia</a></span></figcaption></figure><p><a href="https://www.historic-uk.com/HistoryUK/HistoryofEngland/The-Thames-Frost-Fairs/">Winter frost fairs</a> were common on the frozen River Thames between the 17th and 19th centuries, but they’ve become unimaginable in our lifetime. Over decades and centuries, natural variability in the climate has plunged the UK into sub-zero temperatures from time to time. But global warming is tipping the odds away from the weather we once knew.</p>
<p>These days, people in the UK have become accustomed to much <a href="https://rmets.onlinelibrary.wiley.com/toc/10970088/2020/40/S1">warmer, wetter winters</a>. In fact, winter is warming faster than any other season. This is bad news for those holding out for a white Christmas – the <a href="https://www.metoffice.gov.uk/weather/learn-about/weather/types-of-weather/snow/white-christmas">Met Office reports</a> that only four Christmases in over five decades recorded snow at more than 40% of UK weather stations.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/375339/original/file-20201216-13-xs58p7.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Painting of people, tents and horse-drawn carriages on the frozen river." src="https://images.theconversation.com/files/375339/original/file-20201216-13-xs58p7.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/375339/original/file-20201216-13-xs58p7.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=627&fit=crop&dpr=1 600w, https://images.theconversation.com/files/375339/original/file-20201216-13-xs58p7.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=627&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/375339/original/file-20201216-13-xs58p7.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=627&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/375339/original/file-20201216-13-xs58p7.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=787&fit=crop&dpr=1 754w, https://images.theconversation.com/files/375339/original/file-20201216-13-xs58p7.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=787&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/375339/original/file-20201216-13-xs58p7.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=787&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 frost fair on the River Thames, painted by Thomas Wyke (1683-1684).</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Thomas_Wyke-_Thames_frost_fair.JPG">Thomas Wyke/Wikipedia</a></span>
</figcaption>
</figure>
<p>Christmas is a magical day for many, but meteorologically, it’s no different from other winter periods, when snow and ice are also becoming less common. The Met Office definition of a snow day at a given location in the UK is when snow lies on at least 50% of the ground at 9am. Currently, the Cairngorms around Aviemore receive over 70 snow-lying days per year – the most in the UK. </p>
<p>This amount is smaller than in previous decades though. <a href="https://www.metoffice.gov.uk/research/climate/maps-and-data/data/haduk-grid/haduk-grid">Met Office data</a> shows that, since 1979, the number of snow-lying days has generally decreased by up to five days per decade, and up to ten days per decade in the North Pennines, near Penrith. Around a fifth of the total area of the UK has experienced a significant drop in the prevalence of days with snow lying on the ground.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/374778/original/file-20201214-13-ikelqr.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two maps of the UK depicting the change in prevalence of snow days throughout the UK from 1971-2019." src="https://images.theconversation.com/files/374778/original/file-20201214-13-ikelqr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/374778/original/file-20201214-13-ikelqr.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=270&fit=crop&dpr=1 600w, https://images.theconversation.com/files/374778/original/file-20201214-13-ikelqr.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=270&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/374778/original/file-20201214-13-ikelqr.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=270&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/374778/original/file-20201214-13-ikelqr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=340&fit=crop&dpr=1 754w, https://images.theconversation.com/files/374778/original/file-20201214-13-ikelqr.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=340&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/374778/original/file-20201214-13-ikelqr.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=340&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Snow days are a rarer occasion in the UK today than they were five decades ago.</span>
<span class="attribution"><a class="source" href="https://www.metoffice.gov.uk/research/climate/maps-and-data/data/haduk-grid/haduk-grid">Met Office</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>What causes snow days?</h2>
<p>Snow days are often the result of a meandering <a href="https://theconversation.com/uk/topics/jet-stream-14987">jet stream</a>, the fast-flowing current of air that’s between 9km and 16km above the Earth’s surface. The jet stream normally transports temperate weather from the Atlantic across the UK, but if it’s displaced southwards, it allows persistent high pressure systems of colder air from the north and east, originating in the Arctic or over the Eurasian continent, known as blocking high pressures, to settle over the UK for extended periods. </p>
<p>A number of atmospheric processes can cause the jet stream to meander, but perhaps the most dramatic is when the stratospheric polar vortex, a huge rotating air mass in the middle atmosphere, breaks down. This disruption causes the jet stream to weaken, leading to events such as the infamous 2018 <a href="https://theconversation.com/beast-from-the-east-the-science-behind-europes-siberian-chill-92385">Beast from the East</a>, which brought widespread snowfall to the UK.</p>
<p>The winter of 2018 was not unique in this sense – 2009-2010 and 2013 both brought snowfall because of these dynamic “beasts”. So why is there still a decline in winter snow days in the UK?</p>
<h2>The snows of yesteryear</h2>
<p>There’s no <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017GL073071">strong evidence</a> for a long-term trend in polar vortex disruptions, or other atmospheric processes that influence the jet stream. So the fact that people in the UK have fewer snow days to enjoy each year than they did in the past can’t be blamed on the invisible twists and turns above their heads.</p>
<p>But as the concentration of CO₂ in the atmosphere climbs, disruptions that do occur sit on top of increasing background temperatures, reducing the likelihood of the cold spells that bring widespread snowfall. Just as natural climate trends have lowered the severity of winters since the days of the frost fairs, man-made climate change will increasingly keep the UK’s average temperature above zero.</p>
<p>A heavy covering of snow can transform the country and our perception of it. Snow days, with the closures of schools and workplaces that they bring, evoke fond memories and bring out the child in many as hillslopes and parks become sledging highways. More tangibly, in Scotland, the snowsports industry is estimated to be worth <a href="https://www.pressandjournal.co.uk/fp/news/politics/scottish-politics/1639897/snow-sports-contribute-31m-to-scottish-economy/">over £30 million</a> a year. </p>
<p>But wintry weather can be dangerous too. The cold affects our <a href="https://jech.bmj.com/content/68/7/641.short?casa_token=o9ihfq8efcUAAAAA:bOGF90i4RAl0xKUjj4kx4_Q5D5V0x1364f7nrDXchvqRXC4G90QQroOMV9mp0mfq1BlLi-wrhO0">health</a>, exacerbating heart and lung conditions and <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/748492/the_cold_weather_plan_for_england_2018.pdf">the spread of infectious diseases</a>. In extreme cases, heavy snowfall can cause widespread livestock deaths, which happened in <a href="https://www.belfasttelegraph.co.uk/news/northern-ireland/blizzard-death-toll-for-livestock-hits-44000-29229931.html">Northern Ireland in 2013</a>. The inevitable disruption to travel and businesses can cause economic damage running into <a href="https://www.theguardian.com/uk-news/2018/mar/03/freezing-weather-storm-emma-cost-uk-economy-1-billion-pounds-a-day">billions of pounds</a>, with sectors like the construction industry halted entirely.</p>
<p>While the falling chances of a white Christmas might disappoint many, the current trajectory of less and less snow will at least come as a relief to some.</p><img src="https://counter.theconversation.com/content/152038/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alan Thomas Kennedy-Asser receives funding from NERC.</span></em></p><p class="fine-print"><em><span>Dann Mitchell receives funding from NERC. </span></em></p><p class="fine-print"><em><span>Eunice Lo receives funding from NERC. </span></em></p>Since 1979, the average number of snow days has fallen by about five per decade.Alan Thomas Kennedy-Asser, Research Associate in Climate Science, University of BristolDann Mitchell, Met Office Co-Chair in Climate Hazards, University of BristolEunice Lo, Research Associate in Climate Science, University of BristolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1506622020-11-26T19:12:08Z2020-11-26T19:12:08ZClimate change is making autumn leaves change colour earlier – here’s why<figure><img src="https://images.theconversation.com/files/371524/original/file-20201126-17-6rujb9.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C6000%2C3979&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/5IHz5WhosQE">Chris Lawton/Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>As the days shorten and temperatures drop in the northern hemisphere, leaves begin to turn. We can enjoy glorious autumnal colours while the leaves are still on the trees and, later, kicking through a red, brown and gold carpet when out walking.</p>
<p>When temperatures rise again in spring, the growing season for trees resumes. Throughout the warmer months, trees take carbon dioxide from the atmosphere and store it in complex molecules, releasing oxygen as a byproduct. This, in a nutshell, is the process of photosynthesis. The more photosynthesis, the more carbon is locked away.</p>
<p>We know that carbon dioxide is a major driver of climate change, so the more that can be taken out of the atmosphere by plants, the better. With the warmer climate leading to a longer growing season, some researchers have <a href="https://www.fs.fed.us/nrs/pubs/jrnl/2014/nrs_2014_keenan_001.pdf">suggested</a> that more carbon dioxide would be absorbed by trees and other plants than in previous times. But <a href="https://science.sciencemag.org/cgi/doi/10.1126/science.abd8911">a new study</a> has turned this theory on its head and could have profound effects on how we adapt to climate change.</p>
<h2>Reaching the limit</h2>
<p>The researchers, led by Deborah Zani at the Swiss Federal Institute of Technology, studied the degree to which the timing of colour changes in autumn tree leaves was determined by the growth of the plant in the preceding spring and summer. </p>
<p>Temperature and day length were traditionally accepted as the main determinants of when leaves changed colour and fell, leading <a href="http://max2.ese.u-psud.fr/publications/Delpierre_2009_AFM.pdf">some scientists</a> to assume that warming temperatures would delay this process until later in the season. Studying deciduous European tree species, including horse chestnut, silver birch and English oak, the authors of the new study recorded how much carbon each tree absorbed per season and how that ultimately affected when the leaves fell.</p>
<p>Using data from the <a href="https://www.researchgate.net/profile/Barbara_Templ/publication/323254030_Pan_European_Phenological_database_PEP725_a_single_point_of_access_for_European_data/links/5a8bf0dba6fdcc6b1a442ef2/Pan-European-Phenological-database-PEP725-a-single-point-of-access-for-European-data.pdf">Pan European Phenology
Project</a>, which has tracked some trees for as long as 65 years, the researchers found in their long-term observational study that as the rate of photosynthesis increased, leaves changed colour and fell earlier in the year. For every 10% increase in photosynthetic activity over the spring and summer growing season, trees shed their leaves, on average, eight days earlier.</p>
<p>Climate-controlled experiments on five-year-old European beech and Japanese meadowsweet trees suggest what could be behind this unexpected result. In these trials, the trees were exposed to full sun, half shade or full shade. The results show that there is a limit to the amount of photosynthesis that a tree can carry out over a growing season. Think of it like filling a bucket with water. It can be done slowly or quickly, but once the bucket is full, there is nowhere for any more water to go.</p>
<figure class="align-center ">
<img alt="A misty forest with trees displaying autumn colours." src="https://images.theconversation.com/files/371502/original/file-20201126-21-1rb5f4f.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5933%2C3959&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/371502/original/file-20201126-21-1rb5f4f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/371502/original/file-20201126-21-1rb5f4f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/371502/original/file-20201126-21-1rb5f4f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/371502/original/file-20201126-21-1rb5f4f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/371502/original/file-20201126-21-1rb5f4f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/371502/original/file-20201126-21-1rb5f4f.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">Deciduous trees, which shed leaves in autumn, have a fixed amount of carbon they can absorb per season.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/colorful-tall-beech-trees-close-forest-1717461841">Alex Stemmer/Shutterstock</a></span>
</figcaption>
</figure>
<p>This research shows that deciduous trees can only absorb a set amount of carbon each year and once that limit is reached, no more can be absorbed. At that point, leaves begin to change colour. This limit is set by the availability of nutrients, particularly nitrogen, and the physical structure of the plant itself, particularly the inner vessels which move water and dissolved nutrients around. Nitrogen is a key nutrient which plants need in order to grow, and it’s often the amount of available nitrogen that limits total growth. This is why farmers and gardeners use nitrogen fertilisers, to overcome this limitation.</p>
<p>Together, these constraints mean that carbon uptake during the growing season is a self-regulating mechanism in <a href="https://www.pnas.org/content/111/20/7355">trees</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/31158300/">herbaceous plants</a>. Only so much carbon can be taken up.</p>
<h2>Earlier autumn colours</h2>
<p>In a world with increasing levels of <a href="https://public.wmo.int/en/media/press-release/carbon-dioxide-levels-continue-record-levels-despite-covid-19-lockdown#:%7E:text=The%20annual%20globally%20averaged%20level,per%20million%20benchmark%20in%202015.">carbon in the atmosphere</a>, these new findings imply that warmer weather and longer growing seasons will not allow temperate deciduous trees to take up more carbon dioxide. The study’s predictive model suggests that by 2100, when tree growing seasons are expected to be between 22 and 34 days longer, leaves will fall from trees between three and six days earlier than they do now.</p>
<figure class="align-center ">
<img alt="A pile of yellow and orange maple leaves with a dark red leaf in the middle." src="https://images.theconversation.com/files/371523/original/file-20201126-21-1cmpnob.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/371523/original/file-20201126-21-1cmpnob.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/371523/original/file-20201126-21-1cmpnob.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/371523/original/file-20201126-21-1cmpnob.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/371523/original/file-20201126-21-1cmpnob.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/371523/original/file-20201126-21-1cmpnob.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/371523/original/file-20201126-21-1cmpnob.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">Get ready for this happening a little sooner in the future.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/kAc0En1s1h8">Greg Shield/Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>This has significant implications for climate change modelling. If we accept that the amount of carbon taken up by deciduous trees in temperature countries like the UK will remain the same each year regardless of the growing season, carbon dioxide levels will rise more quickly than was previously expected. The only way to change this will be to increase the capacity of trees to absorb carbon. </p>
<p>Plants that aren’t limited by the amount of nitrogen available may be able to grow for longer in the warming climate. These are the trees which can take nitrogen from the air, such as <a href="https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/british-trees/a-z-of-british-trees/alder/">alder</a>. But these species will still lose their leaves at roughly the same time as always, thanks to less daylight and colder temperatures.</p>
<p>But on the upside, with the prospect of some trees losing their leaves earlier and others losing them at the time they do now, there might be the prospect of prolonged autumnal colours – and more time for us to kick through the leaves.</p><img src="https://counter.theconversation.com/content/150662/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Philip James 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>Warmer temperatures cannot increase the amount of carbon deciduous trees absorb in each growing season, a new study suggests.Philip James, Professor of Ecology, University of SalfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1462882020-10-12T12:18:21Z2020-10-12T12:18:21ZAs COVID-19 cases rise again, how will the US respond? Here’s what states have learned so far<figure><img src="https://images.theconversation.com/files/362963/original/file-20201012-15-n5gh3c.jpg?ixlib=rb-1.1.0&rect=0%2C10%2C6720%2C4456&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">States have tried shutting down bars and limiting restaurants to outdoor seating to slow the coronavirus's spread.</span> <span class="attribution"><a class="source" href="http://gettyimages.com/detail/news-photo/patrons-dine-at-an-outdoor-restaurant-along-5th-avenue-in-news-photo/1227674724">Sandy Huffaker/Getty Images</a></span></figcaption></figure><p>When the coronavirus began spreading in the U.S. in early spring, governors in hard-hit states took drastic steps to reduce the threat and avoid overloading their health care systems. By shutting down nonessential businesses and schools and ordering people to stay home, they slowed the virus’s spread, but <a href="https://www.nytimes.com/2020/09/04/business/economy/jobs-report.html">several million people lost jobs</a>.</p>
<p>Since then, we’ve witnessed a series of ad hoc experiments with more targeted approaches. As states started to reopen, they <a href="https://www.washingtonpost.com/graphics/2020/national/states-reopening-coronavirus-map/">tested</a> different levels of restrictions, such as face mask mandates and capacity constraints on restaurants. Some <a href="https://theconversation.com/how-the-coronavirus-pandemic-became-floridas-perfect-storm-142333">closed bars</a> when cases rose again but left other businesses open. Others set restrictions that would be triggered only for hot spots when a county’s positive case numbers passed a certain threshold.</p>
<p>Now, as cooler weather moves more people indoors and <a href="https://covidtracking.com/data/national">daily case numbers rise</a>, states and communities are looking to those successes and failures as they consider what future strategies should look like. Could more targeted closures and restrictions be effective, or will a return to statewide stay-at-home orders be needed again?</p>
<p>As <a href="https://scholar.google.com/citations?user=me4Q9y4AAAAJ&hl=en">public health</a> <a href="https://scholar.google.com/citations?user=G7AWX0QAAAAJ&hl=en">researchers</a>, we’ve been following the strategies as they evolve, and we see lessons those experiments hold for the country.</p>
<p><iframe id="Q9el6" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/Q9el6/15/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<h2>Better testing and treatment, but a long way to go</h2>
<p>The nation’s ability to respond to the virus has improved since COVID-19 first reached U.S. cities.</p>
<p><a href="https://www.nih.gov/news-events/news-releases/nih-continues-boost-national-covid-19-testing-capacity">Testing capacity</a> has expanded and results are available faster. That means people who become infected can be isolated faster. Treatment methods have also improved. For the most severe cases, innovative use of low-cost <a href="http://doi.org/10.1001/jama.2020.16747">steroids</a> and <a href="https://www.pharmacytimes.com/news/although-research-is-progressing-many-questions-remain-about-covid-19">repositioning patients</a> to support breathing have helped seriously ill patients recover faster.</p>
<p>However, there is still no vaccine, a lot of <a href="http://doi.org/10.1001/jamainternmed.2020.6047">questions remain about new therapies</a>, and shortages are <a href="https://khn.org/news/ppe-shortage-could-last-years-without-strategic-plan-experts-warn/">predicted for personal protective equipment</a> as flu season approaches. </p>
<figure class="align-center ">
<img alt="People stand in line at a clinic offering quick coronavirus testing near Long Beach, California." src="https://images.theconversation.com/files/362764/original/file-20201009-13-1ollk7d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/362764/original/file-20201009-13-1ollk7d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=393&fit=crop&dpr=1 600w, https://images.theconversation.com/files/362764/original/file-20201009-13-1ollk7d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=393&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/362764/original/file-20201009-13-1ollk7d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=393&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/362764/original/file-20201009-13-1ollk7d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=493&fit=crop&dpr=1 754w, https://images.theconversation.com/files/362764/original/file-20201009-13-1ollk7d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=493&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/362764/original/file-20201009-13-1ollk7d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=493&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Rapid tests and more testing supplies at clinics have helped pinpoint coronavirus hot spots. By mid-October, more than 214,000 people with COVID-19 had died in the U.S.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/people-stand-in-line-at-a-clinic-offering-quick-coronavirus-news-photo/1253344313">Brittany Murray/MediaNews Group/Long Beach Press-Telegram via Getty Images</a></span>
</figcaption>
</figure>
<p>With colder weather now arriving, the nation faces a greater potential for virus outbreaks to spread. More person-to-person contact will be inevitable with more indoor activities and in-person classes in schools and colleges. </p>
<p>The upcoming holidays will also mean more inside gatherings and travel. Throughout the pandemic, data have revealed a pattern of increased cases within two weeks of holidays and other events that increase contact and related exposures. For example, an uptick in <a href="https://covidactnow.org/?s=1078236">cases in the Midwest</a> was linked to late summer gatherings around Labor Day and the reopening of colleges. State and local leaders need to be prepared.</p>
<p><iframe id="ALzup" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/ALzup/13/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<h2>So what works?</h2>
<p>From the nationally reported and global case data, it seems clear that requirements for <a href="https://www.healthaffairs.org/doi/10.1377/hlthaff.2020.00818">social distancing and mask-wearing</a> combined with <a href="https://www.nature.com/articles/s41586-020-2405-7">stay-at-home orders and business closures</a> can effectively reduce virus transmission. </p>
<p>New Jersey and New York initially implemented strict, prolonged measures and were able to keep case rates lower through the summer, while several states that quickly lifted restrictions <a href="https://theconversation.com/as-coronavirus-cases-spike-in-the-south-northeast-seems-to-have-the-pandemic-under-control-heres-what-changed-142553">saw their COVID-19 cases surge</a>. But broadly defined shutdowns can have economic drawbacks, so governors are looking for other options.</p>
<p>Two types of more targeted strategies have been able to help keep the virus’s spread under control: focusing on the type of activity and on the locations where transmission risks are higher.</p>
<p>For example, statewide orders kept bars closed in many states since there is a greater risk when people gather in closed surroundings without masks. After Texas closed its bars, limited the number of people in restaurants and began <a href="https://www.texastribune.org/2020/07/24/greg-abbott-texas-lockdown-mask/">requiring people to wear masks</a> in public, its summer COVID-19 spike began to subside. </p>
<p>An MIT study in June <a href="https://doi.org/10.1073/pnas.2008025117">weighed the risk</a> of crowded conditions that could spread COVID-19 against the economic value for several activities to suggest ways to prioritize business closures. It found that those with the highest risk and lowest economic value included liquor stores, cafes, gyms, museums, theaters, sit-down restaurants and hair salons. </p>
<figure class="align-center ">
<img alt="Brianna Soukup/Portland Press Herald via Getty Images" src="https://images.theconversation.com/files/362767/original/file-20201009-19-ckev6m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/362767/original/file-20201009-19-ckev6m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/362767/original/file-20201009-19-ckev6m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/362767/original/file-20201009-19-ckev6m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/362767/original/file-20201009-19-ckev6m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/362767/original/file-20201009-19-ckev6m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/362767/original/file-20201009-19-ckev6m.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">Many bars moved their activities outside when COVID-19 restrictions began.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/patrons-of-bonfire-country-bar-sit-on-the-patio-in-the-news-photo/1227429329">Brianna Soukup/Portland Press Herald via Getty Images</a></span>
</figcaption>
</figure>
<p>In some cases, decision-making about COVID-19 restrictions has largely been in local hands to respond more quickly and in a tailored way. In most states, school districts have made the bulk of decisions about whether to hold in-person classes for K-12 students or keep their classes online. </p>
<p><a href="https://www.law.georgetown.edu/salpal/as-covid-19-proliferates-mayors-take-response-lead-sometimes-in-conflicts-with-their-governors/">Mayors</a>, county judges and other local officials have also had the authority to implement emergency public health restrictions in many areas. That has allowed them to make faster, more surgical strikes against the virus’s spread in hot spots, such as <a href="https://www.nuecesco.com/home/showdocument?id=26203">shutting down beach access</a>, <a href="https://abc7ny.com/covid-spike-compliance-order-shutdown-nyc-coronavirus/6617029/">restricting gatherings in neighborhoods</a> or requiring face masks in hot-spot cities. </p>
<p>New York Gov. Andrew Cuomo <a href="https://www.governor.ny.gov/news/video-audio-photos-rush-transcript-governor-cuomo-announces-new-cluster-action-initiative">ordered a mix of these tactics</a> after COVID-19 cases flared up again in the New York City area in early October. His plan uses <a href="https://www.nytimes.com/2020/10/06/nyregion/cuomo-shutdown-coronavirus.html">targeted closures</a> of schools, bars, restaurants and certain other businesses, such as gyms, in neighborhoods with the highest density of cases. Around the edges of these hot spots, surrounding neighborhoods would face some restrictions, with the restrictions lessening with distance from the hot spot.</p>
<h2>What’s needed to avoid future shutdowns?</h2>
<p>Making these decisions – particularly at the level of detail planned for New York City – depends on having reliable, up-to-date data about how the virus is spreading in communities. That data is also crucial <a href="https://globalepidemics.org/key-metrics-for-covid-suppression/">in counties</a> that have limited health care resources but can quickly implement restrictions to slow the virus’s transmission.</p>
<p>[<em>Deep knowledge, daily.</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>.]</p>
<p>While thresholds, such as positive test rates, can guide shutdowns, it may be more fruitful to focus on activities and practices that allow economies to stay open as much as possible. Protective measures such as wearing masks in public, isolating active cases and avoiding large indoor gatherings can all reduce the virus’s spread.</p>
<p>Communities can learn from the growing evidence and <a href="https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/prevention.html">best practices</a> to tailor their own responses and help avoid the domino effects that could send their economies into another shutdown.</p><img src="https://counter.theconversation.com/content/146288/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 organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>States have been experimenting with more targeted approaches to slow the coronavirus’s spread. Two strategies stand out.Tiffany A. Radcliff, Associate Dean for Research and Professor of Health Policy and Management, Texas A&M UniversityMurray J. Côté, Associate Professor of Health Policy and Management, Texas A&M UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1408562020-07-08T10:51:21Z2020-07-08T10:51:21ZHow animals are coping with the global ‘weirding’ of the Earth’s seasons<figure><img src="https://images.theconversation.com/files/345291/original/file-20200702-57-lzb6c8.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4238%2C2950&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Yellow-bellied marmots are a North American species of ground squirrel.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/yellow-bellied-marmot-on-ridge-near-104145308">Fremme/Shutterstock</a></span></figcaption></figure><p><a href="https://www.bbc.co.uk/news/science-environment-52921479">The UK’s weather did a somersault</a> in the first half of 2020, as the wettest February on record gave way to the sunniest spring. Climate change has warped the environmental conditions that might be considered normal, creating progressively weirder seasons that cause havoc for society. Longer, drier summers increase the risk of crop failure and fires, floods engulf homes, and less winter snowfall and earlier thaws threaten freshwater supplies.</p>
<p>But how do animals cope? Many species have evolved life cycles and strategies for coping with the seasons over millions of years, particularly those in temperate to arctic and alpine environments. Here, seasonal variability is large and predictable. Short and mild summers produce bursts of vegetation and food, the perfect time to give birth to young that can forage to develop their fitness. Long, harsh winters when food is scarce have shaped animals to largely depend on fat reserves for energy, and in extreme cases, to hibernate or migrate.</p>
<p>But as species come to inhabit seasons that no longer resemble those they evolved in, their chances of survival are governed less by their own careful adaptations, and more by the capricious weather. For species eking out an existence in seasonal climates, winter and summer produce distinct challenges of their own. </p>
<h2>Climate change and seasonal survival</h2>
<p>In <a href="https://www.pnas.org/cgi/doi/10.1073/pnas.1918584117">new research</a>, we explored how yellow-bellied marmots in the Colorado Rocky Mountains have responded to climate change. Since the 1970s, every marmot pup born at the study site has been marked, and its life followed year after year. </p>
<p>Marmots are large, burrowing ground squirrels, and they have a distinct seasonal life cycle, with a four-month period during the spring and summer when they’re active and need to gain weight by foraging on plants, and an eight-month period of hibernation during autumn and winter. Marmots, like other burrowing and herbivorous mammals, help shape important habitats and serve as prey for many predators. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/343958/original/file-20200625-33519-1bw1u6p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/343958/original/file-20200625-33519-1bw1u6p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/343958/original/file-20200625-33519-1bw1u6p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/343958/original/file-20200625-33519-1bw1u6p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/343958/original/file-20200625-33519-1bw1u6p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/343958/original/file-20200625-33519-1bw1u6p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/343958/original/file-20200625-33519-1bw1u6p.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">The study site on arrival – thick snow as far as the eye can see.</span>
<span class="attribution"><span class="source">Line Cordes</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>When I first arrived at the <a href="https://www.rmbl.org/">alpine field station</a> in April, I was amazed by the thick layer of snow that reached the roofs of the small wooden cabins dotted around the town of Gothic, named after Gothic Mountain which looms above it. But spring set in and the snow melted, and by midsummer, wildflowers transformed the valley floor.</p>
<p><a href="https://www.theatlantic.com/science/archive/2017/01/billy-barr-climate-change/512198/">Climate records</a> painted a gloomier picture, though. Over the past 40 years, winters have warmed by between two and four degrees Celsius on average, while annual snowfall has declined by three and a half metres. Summers have warmed by two degrees Celsius, lengthened by about 50 days and changed from predominantly wet to predominantly dry.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/343957/original/file-20200625-33528-13yfbiv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/343957/original/file-20200625-33528-13yfbiv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/343957/original/file-20200625-33528-13yfbiv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/343957/original/file-20200625-33528-13yfbiv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/343957/original/file-20200625-33528-13yfbiv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/343957/original/file-20200625-33528-13yfbiv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/343957/original/file-20200625-33528-13yfbiv.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">Summer is warmer, longer and earlier each year.</span>
<span class="attribution"><span class="source">Line Cordes</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>During this time, the chance of marmots surviving a summer has increased, but the chance of surviving the winter hibernation has decreased. The biggest changes in seasonal survival have been noted among younger age classes (the pups and one-year-olds). </p>
<p>We found that lower winter survival tended to be the result of conditions during the previous summer, when heat and drought likely reduced foraging conditions for marmots, leaving them in poor stead for hibernation. </p>
<p>Whether a marmot survived a summer depended on conditions in both seasons. Pups were more likely to survive the summer if it followed a winter with low snowfall. This was most likely because the mothers of these pups were in better condition as forage plants became available sooner after hibernation. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/344544/original/file-20200629-155339-1pvv542.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/344544/original/file-20200629-155339-1pvv542.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/344544/original/file-20200629-155339-1pvv542.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/344544/original/file-20200629-155339-1pvv542.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/344544/original/file-20200629-155339-1pvv542.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/344544/original/file-20200629-155339-1pvv542.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/344544/original/file-20200629-155339-1pvv542.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">A marmot pup.</span>
<span class="attribution"><span class="source">Graeme Shannon</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Unexpectedly, one-year-olds survived better when summers were longer and warmer. It may be that yearlings with their smaller body size are less prone to heat stress compared to adults. Nevertheless, we suspect that their resilience may not last as summers continue to warm and become drier. </p>
<p>Simply focusing on the survival of a species over the entire year may disguise these more dramatic seasonal responses to climate change, lulling us into a false sense of security. And contrasting seasonal responses don’t necessarily cancel each other out. For the marmots, the net change over the year was negative for pups, positive for yearlings, while there was no change for adults. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/animals-will-struggle-to-adapt-fast-enough-to-cope-with-climate-change-study-finds-120857">Animals will struggle to adapt fast enough to cope with climate change, study finds</a>
</strong>
</em>
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<p>The fact that climate change can result in beneficial conditions in one season, and difficult conditions in another has potentially wide-ranging consequences for the persistence of species occupying temperate to more extreme habitats, such as deserts, mountains and polar regions, where the most rapid changes in climate are being observed. Similar findings have emerged from other species around the world, from <a href="https://science.sciencemag.org/content/sci/363/6427/631.full.pdf">meerkats</a> in the Kalahari Desert to <a href="https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1002/ecy.2141?casa_token=bcoHd_UJEGcAAAAA:_t94cyX3IVQHY4CAYNdeRKgHsLBIq0eXOxCXn7oJUUCZNypwmiFJGNvQg8Rkp9fKRQUR5PYLGPBcyA">bighorn sheep</a> in the Canadian Rocky Mountains. </p>
<p>For wildlife living near the poles or near mountain tops, like marmots, there is nowhere to go when conditions slide further and further from optimal.</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">
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<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=Imagineheader1140856">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/140856/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Line Cordes 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>New research on marmots in the US reveals how the topsy-turvy seasons are causing havoc among wildlife.Line Cordes, Lecturer in Marine Population Ecology, Bangor UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1234702019-09-19T13:40:39Z2019-09-19T13:40:39ZWhat does a healthy diet look like for me and the planet? It depends where you live<figure><img src="https://images.theconversation.com/files/293170/original/file-20190919-53507-t0umd4.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5760%2C3837&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/map-world-made-different-kinds-spices-261572543?src=oZWIsGzwCwvEGtn5Q0vT2g-1-3">Africa Studio/Shutterstock</a></span></figcaption></figure><p>I want people to think about the food that they eat not just from “field to fork” but from “seed to soul”. I’ve studied how to make the world’s food supply sustainable for more than 30 years, so people often ask me what’s the best diet for the planet. The problem is, most people want easy answers to that question. Sadly, there are none. </p>
<p>For example, I’ve often thought about becoming vegetarian for ethical and environmental reasons. But I wouldn’t want to eat soya or other foodstuffs imported from the other side of the world because of the carbon emissions involved in transporting them. And if we’re going to acknowledge the ethical quandary of eating animals, what about the animals in the soil? Why is crushing, slicing, and dicing mini beasts in agricultural operations alright, but not for the big beasts? When I follow these arguments through to their full conclusions, I end up as an organic, temperate, fruitarian – only eating fruit grown close to home, without the use of pesticides.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/should-vegans-avoid-avocados-and-almonds-104800">Should vegans avoid avocados and almonds?</a>
</strong>
</em>
</p>
<hr>
<p>When it comes to finding a sustainable diet, there are many contradictions. A concept such as <a href="https://theconversation.com/uk/topics/food-miles-6475">food miles</a> can be helpful for figuring out the carbon emissions involved in bringing particular food items to your plate. It’s simple to understand – but it’s also likely to be meaningless. After all, it’s not just about how far something has travelled, but the environmental cost of that journey and how it was originally produced. </p>
<p>It can be argued that New Zealand lamb consumed in the UK has less of an environmental impact than locally produced lamb. New Zealand lamb production involves <a href="https://www.nzagrc.org.nz/beef-sheep-sector,listing,390,what-options-are-available-to-limit-emissions-growth.html">fewer carbon “rich” inputs</a> such as fertilisers. There is also a highly efficient transport system in New Zealand that is based on bigger farms and bigger lorries – producing and transporting more meat with less land and fewer emissions. This results in less greenhouse gas <a href="https://www.telegraph.co.uk/news/uknews/1553456/Greener-by-miles.html">per kilogram of meat</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/293171/original/file-20190919-53503-155dbm8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/293171/original/file-20190919-53503-155dbm8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/293171/original/file-20190919-53503-155dbm8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/293171/original/file-20190919-53503-155dbm8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/293171/original/file-20190919-53503-155dbm8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/293171/original/file-20190919-53503-155dbm8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/293171/original/file-20190919-53503-155dbm8.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">New Zealand lamb is exported all over the world.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/stunning-landscape-scene-agriculture-rural-area-1091831573?src=jT4il7RQjLYjQ_bFAlTaqg-1-1">Klanarong Chitmung/Shutterstock</a></span>
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<p>But just because things are complicated, it doesn’t mean that we should give up. It’s clear that our health and the planet would benefit if people ate more fruit and vegetables and less meat. Eating seasonal produce, or food fresh from the fields, is a good idea too, particularly as it reconnects people with food and the land in which it’s produced. It forces us to engage with the reality that different crops are produced at different times of the year. Strawberries are a celebration of summer, spring greens of the spring.</p>
<p>But what does a seasonal diet look like for someone living in a temperate climate such as the UK’s? With the help of technology, we can grow many exotic crops in the UK which would otherwise perish in the climate. The problem is that much of this involves carbon-hungry technology, such as glasshouses heated by burning gas or vast fields of plastic polytunnels. </p>
<p>What would our diet look like if we grew all our food within the natural seasons and climate of our local area?</p>
<h2>Dinner dates</h2>
<p>Summer is great as we can feast on a wide range of fruits and vegetables. It’s easier during this season to follow the health advice to eat the rainbow. That is, to eat as broad a spectrum of colourful fruit and vegetables as possible. British summer affords strawberries, radishes, tomatoes and blueberries.</p>
<p>There are salads and summer puddings to enjoy for an injection of other colours, particularly green. If people are clever, many crops can be preserved for the coming winter. Ironically, during summer when much of our natural produce is plentiful, the UK still imports much of its food. </p>
<p>As we move into autumn, unless crops are protected by growing them inside a glasshouse or polytunnel, many of the more delicate foodstuffs start to wither away. We become increasingly dependent on roots such as beetroot, carrots, potatoes, swede and parsnips, and the leafy brassicas such as Brussels sprouts, cabbage, cauliflower and kale. Of course there are other ingredients – let’s not forget leeks and swiss chard – but this is a time to hunker down and embrace what the Scandinavians call “hygge”. Getting cosy and comfortable with stews, soups and broths.</p>
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<img alt="" src="https://images.theconversation.com/files/293173/original/file-20190919-53515-mnzt0h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/293173/original/file-20190919-53515-mnzt0h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/293173/original/file-20190919-53515-mnzt0h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/293173/original/file-20190919-53515-mnzt0h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/293173/original/file-20190919-53515-mnzt0h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/293173/original/file-20190919-53515-mnzt0h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/293173/original/file-20190919-53515-mnzt0h.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">Autumn – a time for root veg and brassicas.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/HfH5yd70ox8">Arnaldo Aldana/Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p>Things get more austere as winter progresses. This is one reason why our ancestors had midwinter feasts around Christmas and the winter solstice. Nights were long, they needed to have a party to forget the winter and look forward to spring. Even in late February and March, when we start thinking of spring, there’s a hidden problem – the hunger gap. This is when the autumn crops that have survived through winter start to die off and the spring crops are yet to come. </p>
<p>Little things such as purple sprouting broccoli – also known as poor people’s asparagus – can offer some solace as they are ready to eat in winter. Of course, we can also preserve food from one season to another, but this requires energy. There are traditional skills that require less energy, but at the same time demand increasingly rare knowledge and time. </p>
<p>For example, how many people bottle their surplus fruit and vegetables or pickle eggs? Consuming local seasonal food in large amounts throughout the year will mean restructuring traditional food production systems and supply chains. These have been decimated by the concentration of food supply in the hands of fewer and fewer retailers and contract caterers. Winter would test our ability to preserve the bounty of summer and autumn, but spring would relieve us with artichokes, beetroot, new potatoes, rhubarb, rocket, sorrel and spinach. After that, the cycle begins again.</p>
<p>As I say, a truly sustainable food supply isn’t going to be simple. Much of it involves reviving cultural knowledge and processes that commercial supermarket chains have replaced. But the rewards of a local and seasonal food supply are great for nature and your health. Reconnecting with the land and its seasonal rhythms could do us all a great amount of good.</p>
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<img alt="" src="https://images.theconversation.com/files/290123/original/file-20190829-106524-1w6rzla.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/290123/original/file-20190829-106524-1w6rzla.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=446&fit=crop&dpr=1 600w, https://images.theconversation.com/files/290123/original/file-20190829-106524-1w6rzla.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=446&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/290123/original/file-20190829-106524-1w6rzla.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=446&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/290123/original/file-20190829-106524-1w6rzla.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=560&fit=crop&dpr=1 754w, https://images.theconversation.com/files/290123/original/file-20190829-106524-1w6rzla.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=560&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/290123/original/file-20190829-106524-1w6rzla.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=560&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p class="fine-print"><em><span>Sean Beer 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 seasonal diet could reconnect people with nature’s rhythms.Sean Beer, Senior Lecturer in Agriculture, Bournemouth UniversityLicensed as Creative Commons – attribution, no derivatives.