tag:theconversation.com,2011:/columns/james-dyke-96221Eccentric orbits – The Conversation2016-06-06T19:03:41Ztag:theconversation.com,2011:article/605832016-06-06T19:03:41Z2016-06-06T19:03:41Z‘Pristine’ landscapes haven’t existed for thousands of years, says new study<figure><img src="https://images.theconversation.com/files/125391/original/image-20160606-13080-s7o3qu.jpg?ixlib=rb-1.1.0&rect=273%2C0%2C2639%2C1379&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption"></span> <span class="attribution"><span class="source">Galyna Andrushko / shutterstock</span></span></figcaption></figure><p>What is natural? What is artificial? It is often assumed that natural is better than artificial. Getting back to nature is something we should aspire to, with kids in particular not spending enough time in nature. But if you want to escape civilisation and head into the unaltered wilderness you may be in for a shock: it doesn’t exist.</p>
<p>New research now suggests that there are practically no areas that have escaped human impacts. But not only that, such impacts happened many thousands of years earlier than is usually appreciated. In fact, you’d have to travel back more than 10,000 years to find the last point when most of the Earth’s landscapes were unaffected by humans.</p>
<p>The study, published in the <a href="http://dx.doi.org/10.1073/pnas.1525200113">Proceedings of the National Academies of Sciences</a> and led by <a href="http://www.arch.ox.ac.uk/NB1.html">Nicole Boivin</a> of the University of Oxford, catalogued changes in the abundance and diversity of plants and animals at the same time as human societies and technologies spread across the globe.</p>
<p>There is good fossil evidence for modern humans – <em>Homo sapiens</em> – being present in East Africa as far back as <a href="http://www.nature.com/nature/journal/v433/n7027/abs/nature03258.html">195,000 years ago</a>. Some 180,000 years later, humans were found on every continent except Antarctica. Over this period there were a series of collapses in biodiversity, with particular instances of <a href="https://theconversation.com/dna-evidence-proves-climate-change-killed-off-prehistoric-megafauna-45080">extinctions of megafauna</a>, non-domesticated land animals weighing more than 44kg. </p>
<p>Between 50,000 to 10,000 years ago, at least 101 of the 150 groups of <a href="http://www.pnas.org/content/105/Supplement_1/11543.abstract">megafauna species became extinct</a>. There is much debate as to whether the disappearance of megafauna such as mammoths or mastodons was a direct result of human hunting, or a response to other factors. Correlation does not necessarily lead to causation: so evidence that large number of species disappeared from some regions around the same time as humans appearing could be due to a common factor such as changes in climate as the glaciers of the last ice age retreated. </p>
<p>Boivin’s study doesn’t produce a smoking gun that proves humans were responsible for such extinctions. Rather it uses traditional and new archaeological techniques to produce flint axes, plant pollen and burnt forest remains as evidence of the impacts humans had. </p>
<p>Extinction grabs our attention, but the data the international team has assembled tells a story of rapid change in not just the total number of species around the time that humans appear, but also the numbers of individual plants and animals in these ecosystems. Hunting and land clearing are the two main culprits in the oldest period they study – the Late Paleolithic (ending 10,000 years ago).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/125395/original/image-20160606-13043-q7lmla.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/125395/original/image-20160606-13043-q7lmla.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/125395/original/image-20160606-13043-q7lmla.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=152&fit=crop&dpr=1 600w, https://images.theconversation.com/files/125395/original/image-20160606-13043-q7lmla.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=152&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/125395/original/image-20160606-13043-q7lmla.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=152&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/125395/original/image-20160606-13043-q7lmla.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=191&fit=crop&dpr=1 754w, https://images.theconversation.com/files/125395/original/image-20160606-13043-q7lmla.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=191&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/125395/original/image-20160606-13043-q7lmla.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=191&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 study maps the spread of crops like wheat (A, in red) and livestock (Cattle, in blue) against the spread of human civilisation.</span>
<span class="attribution"><span class="source">Boivin et al / PNAS</span></span>
</figcaption>
</figure>
<p>After that, impacts shift up a gear with the development and rapid spread of agriculture. By this time roving bands of hunter gatherers begin to settle and plant crops and herd cattle. Today, we are used to looking out of an aircraft window to see broad expanses of intensively farmed monoculture crops. This trend began with the very first farmers who replaced diverse habitats with a small number of cultivated plants that in time would spread across the Earth, replacing whatever ecosystems they encountered. </p>
<p>The development of agriculture also included the domestication of animals, a few of which have expanded their ranges along with humans. Domestication of chickens happened some 10,000 years ago in East Asia. Earth is now home to over 20 billion chickens, making it the most abundant bird species by some margin. The <a href="http://www.vaclavsmil.com/wp-content/uploads/PDR37-4.Smil_.pgs613-636.pdf">vast majority</a> of the mass of land animals is now made up of humans and their domesticated species of cattle, pigs, sheep, goats and chickens.</p>
<p>When you include the accidental introduction of <a href="http://www.nature.com/news/invasive-species-the-18-km2-rat-trap-1.12992">animals such as rats</a> and invasive plant species, human agriculture meant profound alteration or sometimes complete replacement of indigenous ecosystems. The starkest examples of such changes are to be found on islands which often have high numbers of species that are not found anywhere else. Some examples are documented in more recent human history – the 17th-century extinction of the flightless dodo from the island of Mauritius being the most famous.</p>
<p>As well as detailing some of the havoc that humans have wrought on the biosphere, the researchers also highlight some positive interactions humans had. For example, the long presence of <a href="http://www.ncbi.nlm.nih.gov/pmc/article">prehistoric societies</a> that flourished within the Amazon basin show that careful stewardship of ecological resources – in that instance the cultivation of rich productive soils – can enhance ecosystems and provide sustainable livelihoods. </p>
<p>This is perhaps the most important lesson gained from the study. If we are to feed and care for <a href="https://www.un.org/en/development/desa/news/population/un-report-world-population-projected-to-reach-9-6-billion-by-2050.html">the nine billion people</a> that will be living on Earth by the middle of this century, then we need a more subtle and complex understanding of nature and sustainability. </p>
<p>The industrial age we now live in has taken human impacts to a planetary scale. We are changing the global climate and some argue that we have become a <a href="https://theconversation.com/dawn-of-the-anthropocene-five-ways-we-know-humans-have-triggered-a-new-geological-epoch-52867">geological force</a>. We can neither get back to nature nor continue as we are. </p>
<p>The <a href="http://cw.routledge.com/textbooks/alevelphilosophy/data/AS/WhyShouldIBeGoverned/Stateofnature.pdf">state of nature</a> – the situation of humans before the formation of societies – is a well used thought experiment in philosophy. It asks us to consider how societies and governments arise. What makes a good society? What is the moral basis of taxation? </p>
<p>An <em>ecological</em> state of nature – the biosphere as it was before human interference – is sometimes used in a very limited way when managing contemporary ecosystems. The assumption can be that we should simply strive to revert them back to their natural state. But can we say what that state is? Alternatively, it could be used to pose both philosophical and practical questions. What sort of Earth system do humans want to live on? What is the role of other species in human well-being? What is the moral status of non-human animals? </p>
<p>Research that probes our ancient interactions with the rest of life on Earth can help us address such questions and so understand our current predicament. It remains to be seen whether <em>Homo sapiens</em> – which let’s remember is Latin for wise person – have the intelligence to learn from past mistakes and forge a sustainable future on Earth.</p><img src="https://counter.theconversation.com/content/60583/count.gif" alt="The Conversation" width="1" height="1" />
If you want to escape civilisation and head into the unaltered wilderness you may be in for a shock: it doesn’t exist.James Dyke, Lecturer in Sustainability Science, University of SouthamptonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/573272016-04-07T10:16:24Z2016-04-07T10:16:24ZGreat Barrier Reef disaster is the latest harbinger of a global mass extinction<figure><img src="https://images.theconversation.com/files/117835/original/image-20160407-16263-178ebyo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Recent aerial surveys found huge amounts of coral bleaching in the Great Barrier Reef.</span> <span class="attribution"><span class="source">Terry Hughes/ARC Centre of Excellence for Coral Reef Studies</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Large sections of the Great Barrier Reef, the Earth’s largest living structure, are <a href="https://theconversation.com/coral-bleaching-taskforce-more-than-1-000-km-of-the-great-barrier-reef-has-bleached-57282">dying before our eyes</a>. Sustained high sea temperatures have stressed the corals to the point where they expel the brightly coloured algae that live within their tissues. This process is aptly named bleaching as it removes all pigment and exposes the shocking white calcium skeleton of the reef structures. </p>
<p>The coral can survive in this state for up to a few weeks. Thereafter, if temperatures do not decrease then they will die. </p>
<p>The Great Barrier Reef has experienced bleaching events <a href="http://www.gbrmpa.gov.au/managing-the-reef/threats-to-the-reef/climate-change/what-does-this-mean-for-species/corals/what-is-coral-bleaching">twice before</a>. The first, in 1998, was bad enough, with 50% of the reef affected. 2002 was even worse with 60% of the reef bleached. Recent aerial surveys of the northern 1000km of the reef evaluated 500 different sections – <a href="http://www.coralcoe.org.au/media-releases/scientist-witnesses-severe-coral-bleaching">95% were bleached</a>. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"715309461020082176"}"></div></p>
<p>The full impact that such bleaching is having will not be known until biologists directly observe the corals in the water. Estimates coming back from initial monitoring show that on some reefs more than half of the coral has already died. </p>
<p>Given the <a href="https://theconversation.com/we-have-12-months-until-the-next-hottest-year-memo-will-we-be-ready-53460">record-shattering temperatures</a> over the past year, coral researchers were preparing themselves for another mass bleaching. But the scale of this event has left some researchers stunned. Or <a href="https://twitter.com/ProfTerryHughes/status/716272793139064833">angry</a>. Returning from five weeks investigating the reefs, Jodie Rummer, a biologist at the <a href="http://www.coralcoe.org.au/media-releases/scientist-witnesses-severe-coral-bleaching">ARC Centre of Excellence for Coral Reef Studies</a> said:</p>
<p>“I witnessed a sight underwater that no marine biologist, and no person with a love and appreciation for the natural world for that matter, wants to see”. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/RRxBtL35MuU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Patches of bleached coral are everywhere.</span></figcaption>
</figure>
<p>Many are asking the simple question – why is this happening? First, we need to stress that there was not a single coral bleaching event on the Great Barrier Reef in the <a href="http://www.abc.net.au/news/2016-03-28/great-barrier-reef-coral-bleaching-95-per-cent-north-section/7279338">400 years prior to 1998</a>. While the current <a href="https://theconversation.com/el-nino-could-mean-2015-is-even-hotter-than-last-years-scorcher-35837">extreme El Niño</a> is playing a part in this latest episode of coral destruction, the underlying driver is increasing global temperatures as a consequence of human-made climate change. </p>
<h2>Why corals need their colour</h2>
<p>Coral polyps and their colourful zooxanthellae algae have a tightly coupled relationship, where each aids the other. </p>
<p>The algae are autotrophic photosynthesisers, which means they make their own food by using sunlight to split carbon dioxide molecules and form sugars. Coral polyps are much more complex heterotrophs – they use fine-meshed sieves to sweep up suspended organic matter from sea water. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/117727/original/image-20160406-28940-kvwrau.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/117727/original/image-20160406-28940-kvwrau.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/117727/original/image-20160406-28940-kvwrau.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=426&fit=crop&dpr=1 600w, https://images.theconversation.com/files/117727/original/image-20160406-28940-kvwrau.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=426&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/117727/original/image-20160406-28940-kvwrau.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=426&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/117727/original/image-20160406-28940-kvwrau.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=535&fit=crop&dpr=1 754w, https://images.theconversation.com/files/117727/original/image-20160406-28940-kvwrau.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=535&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/117727/original/image-20160406-28940-kvwrau.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=535&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
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<span class="attribution"><a class="source" href="http://oceanservice.noaa.gov/facts/coralbleaching-large.jpg">NOAA</a></span>
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</figure>
<p>For the algae, a coral reef represents the perfect place to live. There, they are safe and secure within a strong structure, near the surface and so able to receive large amounts of energy from the sun along with coral polyp waste, which helps promote photosynthesis. In fact photosynthesis is so productive that the algae produce more food than they can consume. This surplus is greedily gobbled up by the coral polyps. It’s a win-win situation – what biologists call a <a href="http://www.els.net/WileyCDA/ElsArticle/refId-a0003281.html">mutualistic symbiosis</a>.</p>
<p>However, just like any biological process there are environmental limits. Higher temperatures along with very bright sunshine can impact both coral polyps and their algae and their relationship breaks down, leading to the expulsion of the algae and bleached coral.</p>
<p>Bleaching can also be driven by pollution, <a href="http://oregonstate.edu/ua/ncs/archives/2013/nov/large-study-shows-pollution-impact-coral-reefs-%E2%80%93-and-offers-solution">particularly agricultural run-off</a> and sedimentation from activities such as dredging. These two factors threaten the more southern portions of the Great Barrier Reef which at least so far have dodged some of the very worst bleaching as sea temperatures have been lower. The northern stretch of the reef is more remote and better protected from human impacts, but it has borne the brunt of extreme temperatures. </p>
<h2>Our response…</h2>
<p>Given that scientists have been warning about a significant bleaching episode for <a href="http://www.abc.net.au/news/2015-12-19/scientists-brace-coral-bleaching-great-barrier-reef-2016/7042658">some time now</a>, one may have hoped for a coordinated response to this predictable disaster. There have indeed been related developments. </p>
<p>While biologists were in the air and <a href="http://www.coralcoe.org.au/media-releases/national-coral-taskforce-unleashes-an-armada-of-experts">under the water</a> scrambling to understand the severity of this latest bleaching event, the Queensland Government <a href="http://www.couriermail.com.au/news/queensland/adani-coal-mining-project-could-begin-construction-in-2017/news-story/09d391a67271e96d28845ec0049877a4">approved mining leases</a> for the A$21.7 billion Carmichael coal mine and associated new rail line in the Galilee Basin. If all of this coal is extracted and burnt, some <a href="https://theconversation.com/the-carmichael-mine-lease-shows-that-decisions-on-coal-need-a-much-wider-perspective-57276">4.6 billion tons of carbon dioxide</a> will be released into the Earth’s atmosphere. </p>
<p>Given climate change’s obvious impact on the Great Barrier Reef, some scientists have pointed out the <a href="http://www.smh.com.au/federal-politics/political-news/decision-on-coal-mine-defies-reason-20160403-gnxbc6.html">fundamental contradiction</a> in a government stating that it is both committed to protecting the reef and developing these new coal mines. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/117737/original/image-20160406-29010-1wvispp.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/117737/original/image-20160406-29010-1wvispp.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/117737/original/image-20160406-29010-1wvispp.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=648&fit=crop&dpr=1 600w, https://images.theconversation.com/files/117737/original/image-20160406-29010-1wvispp.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=648&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/117737/original/image-20160406-29010-1wvispp.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=648&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/117737/original/image-20160406-29010-1wvispp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=815&fit=crop&dpr=1 754w, https://images.theconversation.com/files/117737/original/image-20160406-29010-1wvispp.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=815&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/117737/original/image-20160406-29010-1wvispp.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=815&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Abbot Point is just 19km from the nearest coral. The Galilee Basin is at the bottom-left.</span>
<span class="attribution"><span class="source">Google Maps</span></span>
</figcaption>
</figure>
<p>As if adding insult to injury, the vast majority of the Galilee Basin coal will be shipped out of the deep water port of <a href="http://www.nqbp.com.au/abbot-point/">Abbot Point</a> which is within the <a href="http://whc.unesco.org/en/list/154">Great Barrier Reef UNESCO world heritage site</a>. Those shipping the coal will be able to wave goodbye to the reef in more than one way as they transport it to power stations in India, China and Japan where it will be burnt and so contribute to further warming and further bleaching. </p>
<p>At times like this, it’s hard not to anthropomorphise – to see the Great Barrier Reef and other coral reefs around the world turning white not due to bleaching, but in shock at our sustained attack on the natural world. The events unfolding off the coast of north eastern Australia are dramatic, but are also just the latest manifestation of the <a href="https://theconversation.com/earths-sixth-mass-extinction-has-begun-new-study-confirms-43432">mass extinction event</a> humans have initiated.</p>
<p>This not only drains the colour from the Earths’ most magnificent aquatic ecosystems, but robs us of biological beauty across the world. We will all lead diminished lives because of it.</p><img src="https://counter.theconversation.com/content/57327/count.gif" alt="The Conversation" width="1" height="1" />
Warm seas are causing coral ‘bleaching’ in one of the world’s biodiversity hotspots.James Dyke, Lecturer in Sustainability Science, University of SouthamptonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/534602016-01-21T17:25:56Z2016-01-21T17:25:56ZWe have 12 months until the next ‘hottest year’ memo – will we be ready?<figure><img src="https://images.theconversation.com/files/108754/original/image-20160120-26129-1148e0g.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5176%2C3445&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">FotoMacht / shutterstock.com</span></span></figcaption></figure><p>It’s official. 2015 was the <a href="http://www.bbc.co.uk/news/science-environment-35354579">warmest year ever recorded</a>. In fact, one would need to go back <a href="http://theconversation.com/the-last-time-earth-was-this-hot-hippos-lived-in-britain-thats-130-000-years-ago-53398">some 130,000 years</a> to experience such high surface temperatures. </p>
<p>This really just confirms what we already assumed. The <a href="https://theconversation.com/el-nino-could-mean-2015-is-even-hotter-than-last-years-scorcher-35837">monster El Niño</a> that began to erupt towards the end of 2014 further amplified the background signal of global warming that is being driven by greenhouse gas emissions. While the forecast is for a diminishing El Niño as we move towards the northern hemisphere summer, it hasn’t done with us yet – 2016 may prove to be <a href="http://www.metoffice.gov.uk/news/releases/archive/2015/global-temperature">even warmer</a>. </p>
<p>Beyond this year temperatures may decrease. For a while. This of course will be seized upon by some people who continue to dispute the Earth is experiencing significant and sustained warming – let alone that humans are primarily responsible for such a trend. People with this attitude have fallen for the “escalator” fallacy; it’s possible to show a short-term decrease in temperature if you pick your start and end times carefully, but looking at the longer-term produces a clear increasing trend. </p>
<figure> <img src="http://www.skepticalscience.com/graphics/Escalator500.gif"><figcaption>Going down the up escalator. Source: skepticalscience ‘The Escalator’. Data: NASA GISS</figcaption></figure>
<p>Really, assessing man-made climate change is about sorting out the signal from the noise. But while the differences we are talking about here are fractions of degrees, the impacts are not negligible. </p>
<p>Global climate change is measured in averages which smear out and can obscure what is in effect local weather and local impacts. Enhanced El Niños cause extreme flooding and drought either side of the Pacific, for instance, with weather going haywire potentially across the entire planet. Coral reefs are threatened, as are regions in the Amazon, and we’re likely to see increased desertification, more extreme droughts and more damaging floods in a warmer world. </p>
<p>At this point it would be easy to become rather depressed. These things will not only directly impact us in the future, but are making their effects known to us right now. </p>
<p>Regions in the UK appear to be experiencing “<a href="http://www.bbc.co.uk/programmes/p03bd6bd">100-year floods</a>” every few years. Prime minister David Cameron’s fixed grimace of concern yet steely resolve is getting regular outings now. It’s certainly unfortunate that the Environment Agency that is responsible for flood prevention and management suffered a series of very large <a href="http://www.theguardian.com/environment/2014/feb/28/environment-agency-staff-voluntary-redundancy">cuts in funding and staff</a> during this and the previous government. Still, Cameron assured all those involved that things would be fixed. Whatever it takes, whatever it costs.</p>
<p>Of course, the risk is that the current prime minister and those who succeed him will be doomed to play the role of King Canute. This modern incarnation of the <a href="http://www.bbc.co.uk/news/magazine-13524677">ancient fable</a> would involve arguing with the ever-increasing energy content of the Earth’s atmosphere, land and oceans with a range of privatised environmental services and free market solutions. </p>
<h2>The fallibility of free markets</h2>
<p>The thing is, climate change represents the ultimate failure of the free market, which is unable to effectively price the damage it is doing. Carbon emitted from burning fossil fuels is an <a href="http://www.investopedia.com/terms/e/externality.asp">externality</a>, which is economics speak for causing a mess that someone else has to pick up the tab for. Carbon trading schemes <a href="http://www.neweconomics.org/blog/entry/energy-round-up-carbon-markets-have-failed">haven’t successfully reduced emissions</a> as carbon cannot be priced sensibly in the absence of state intervention. Some have argued <a href="http://www.worldwatch.org/node/5962">that a carbon tax</a> would be much more effective, but this would need coordinated international agreements – and the political will to enforce them. </p>
<p>The agreement in Paris last December was a crucial step towards avoiding dangerous climate change. But <a href="https://theconversation.com/how-emissions-trading-at-paris-climate-talks-has-set-us-up-for-failure-52319">the pathology is still there</a>. We are still gripped by the need to grow economies and for that growth to be powered by fossil fuels. </p>
<p>Last year there was some excitement about the <a href="http://www.iea.org/newsroomandevents/news/2015/march/global-energy-related-emissions-of-carbon-dioxide-stalled-in-2014.html">decoupling of growth from carbon emissions</a>; for the first time in 40 years the increase in global GDP in 2014 was accompanied by a decrease in carbon emissions. Like Paris, this is good news. But the differences here are very small. </p>
<p>If we want to seriously avoid not just 2°C warming but arguably <a href="https://theconversation.com/what-next-after-paris-time-to-listen-to-those-most-at-risk-from-climate-change-50943">the much more important 1.5°C</a>, then emissions must start falling fast in the developed nations right now. And they must continue to fall every year. At the same time we need massive investment in developing nations, to help them decrease poverty and improve well-being while avoiding the high-carbon mistakes made in the now-industrialised world.</p>
<p>At this point, confirmation that 2015 was the warmest year on record tells us that what we need now are not trends but step changes. In 12 months time we will receive the same memo. We have a rapidly decreasing amount of time to respond to it.</p><img src="https://counter.theconversation.com/content/53460/count.gif" alt="The Conversation" width="1" height="1" />
What we need now are not ‘positive trends’ on emissions, but radical step changes.James Dyke, Lecturer in Complex Systems Simulation, University of SouthamptonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/509432015-12-18T11:10:58Z2015-12-18T11:10:58ZWhat next after Paris? Time to listen to those most at risk from climate change<p>Pick any day over the past few weeks and the mainstream media would have told you that the COP21 Paris climate change negotiations were crucial and productive, an irrelevant sideshow, doomed to failure, or even humanity’s <a href="https://www.newscientist.com/article/mg22830494-000-paris-climate-summit-hope-versus-reality-at-last-ditch-meeting/">last ditch</a> attempt to avoid climate catastrophe.</p>
<p>Dig a little deeper into the internet and you will discover that such United Nations events are in fact an attempt to establish a <a href="http://www.endtime.com/endtime-magazine-articles/global-warming-climate-change-scaring-us-accepting-world-government/">world government</a>, replete with eye-watering taxes. </p>
<p>Conspiracy theories aside, what actually happened in Paris is that humans came up with an agreed plan to put a brake on climate change. We won’t reverse global warming but we should slow it down. </p>
<p>If we don’t come to our collective senses and rapidly reduce carbon emissions, then we will have to revert to drastic <a href="http://www.bbc.com/news/science-environment-30197085">geoengineering</a> to rein in further warming. There is no guarantee that such climate brakes will work. If they fail, our civilisation will be on a collision course with a hotter planet. </p>
<h2>Do no harm – to climate and people</h2>
<p>The challenge we face is not only to avoid a global collapse of civilisation many decades in the future, but also to avoid harm right now.</p>
<p>Polar bears, for instance, have become an unofficial mascot of climate change. A warmer world will have less ice, and fewer places for them to hunt and breed. Yet they aren’t exceptional in this respect. If we tip the climate into runaway warming, then up to one in six of all species are <a href="https://theconversation.com/one-in-six-species-faces-extinction-as-a-result-of-climate-change-41018">threatened with extinction</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/106481/original/image-20151217-8068-1lrtiuf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/106481/original/image-20151217-8068-1lrtiuf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=334&fit=crop&dpr=1 600w, https://images.theconversation.com/files/106481/original/image-20151217-8068-1lrtiuf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=334&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/106481/original/image-20151217-8068-1lrtiuf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=334&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/106481/original/image-20151217-8068-1lrtiuf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=419&fit=crop&dpr=1 754w, https://images.theconversation.com/files/106481/original/image-20151217-8068-1lrtiuf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=419&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/106481/original/image-20151217-8068-1lrtiuf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=419&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Global warming is bad news for bears.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/puliarfanita/22204505689/">Anita Ritenour</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>However, the harm I am talking about is not to bears, bats or beetles, but humans. A warmer world <a href="https://www2.ametsoc.org/ams/index.cfm/publications/bulletin-of-the-american-meteorological-society-bams/explaining-extreme-events-from-a-climate-perspective/table-of-contents/low-resolution-version/">means storms</a> with more destructive power. More <a href="http://floodlist.com">floods</a> and landslides at the same time as more drought and crop failures. </p>
<p>These impacts are not going to be equally distributed across the world. They are going to disproportionately impact the very poorest. When you factor in the increase in diseases such as malaria, then the prospects for some are <a href="https://www.ucl.ac.uk/global-health/project-pages/lancet1/ucl-lancet-climate-change.pdf">very grim</a>. </p>
<p>Countries <a href="http://www.wsj.com/articles/developing-nations-push-for-tougher-target-in-climate-change-talks-1445625743">most affected by climate change</a> drove the formation of the <a href="http://www.theguardian.com/environment/2015/dec/08/coalition-paris-push-for-binding-ambitious-climate-change-deal">high ambition coalition</a> that was key in getting the 1.5°C limit of warming in the agreement. This is further away from potential runaway warming, but the agreed text speaks in terms of pursuing efforts and aspirations. We must do better. African nations and low-lying islands are most at risk – and least responsible for the problem of climate change. They must be given a forum, and be properly listened to over the coming years. </p>
<h2>Fair and just</h2>
<p>Richer nations reducing their carbon emissions and paying developing nations to leapfrog some of the worse excesses of fossil-fuelled development is not some gift, or act of international largess. It’s what is fair, right and just. Not to do that would be to effectively shrug our shoulders and say: sorry, we got here first. </p>
<p>Most of the change in the Earth’s climate is a consequence of carbon that was emitted many years ago. Take the UK for example. While its current emissions may be much smaller than the emissions of developing nations such as China or India, the <a href="http://www.carbonbrief.org/interactive-map-historical-emissions-around-the-world">cumulative emissions of greenhouse gasses</a> means that it is still an important contributor to climate change. This means that responsibilities to address climate change <a href="http://unfccc.int/resource/docs/2015/cop21/eng/l09r01.pdf">should be differentiated</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/6lJ2uZSRfHI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A Short History of Global Emissions from Fossil-Fuel Burning (1750-2010)</span></figcaption>
</figure>
<p>It’s easy to feel very pessimistic about the international community’s ability to do the right thing. But we would be wrong to buy into a narrative of fatalism. Not only is there nothing physically impossible about rapidly transitioning away from fossil fuels, there is ample demonstration that humans are able to look beyond their friends, families and communities and consider the well-being of others. There have been countless <a href="http://www.huffingtonpost.com/entry/syrian-refugee-feeds-berlin-homeless_5654b766e4b0879a5b0cb708">acts of kindness</a> in response to the European refugee crisis. I recently wrote about <a href="https://theconversation.com/dont-wait-for-global-politics-to-fix-climate-change-we-can-do-it-ourselves-50687">local communities taking actions themselves</a> to tackle climate change. In these and other cases, the motivation to act is to shoulder a responsibility and help reduce suffering, to help build a solution.</p>
<p>While some humans may be selfish and self interested, <em>Homo sapiens</em> as a species are not. We are extraordinarily <a href="http://www.wired.com/2011/11/humans-social/">social animals</a>. Climate change is a global phenomenon that is driving the rapid evolution of moral codes and laws. In that respect it can even change the world for the better. For that to happen we must realise that we are part of a planetary community and that what we do matters.</p><img src="https://counter.theconversation.com/content/50943/count.gif" alt="The Conversation" width="1" height="1" />
Low-lying islands helped guide the ambitious narrative of COP21 – next time, they should guide the policy.James Dyke, Lecturer in Complex Systems Simulation, University of SouthamptonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/506872015-11-30T05:54:16Z2015-11-30T05:54:16ZDon’t wait for global politics to fix climate change – we can do it ourselves<p>It’s now almost certain that 2015 will be the <a href="https://www.wmo.int/media/content/wmo-2015-likely-be-warmest-record-2011-2015-warmest-five-year-period">warmest year ever recorded</a>. However, rather than reduce green house gas emissions – something that has to happen quite urgently in order to avoid crashing through the safety barrier of 2°C warming – we continue to pump more into the atmosphere.</p>
<p>Thus far, the collective international response to climate change has been similar to a frog passively sitting in heated pan of water. We are in danger of being cooked alive from inaction. </p>
<p>We will have to wait and see if the latest and largest <a href="http://www.cop21paris.org/about/cop21">UN climate change summit</a> in Paris will buck this trend and produce effective responses to climate change. Previous meetings have exposed a bewildering spectrum of issues, concerns, vested interests and general political dysfunction. By comparison, the <a href="https://theconversation.com/how-does-the-ipcc-know-climate-change-is-happening-33704">physical science of climate change</a> is simple. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/WtPkFBbJLMg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">170 years of global warming.</span></figcaption>
</figure>
<p>Why has it proved so difficult to agree to limit carbon emissions?</p>
<p>One reason stems from the fact the Earth’s atmosphere is a <a href="http://www.investopedia.com/terms/p/public-good.asp">public good</a>, just like street lighting, schools or public parks. A public good is <a href="http://www.investopedia.com/terms/r/rival_good.asp">non-rivalrous</a> in that my use of it does not reduce your or anyone else’s access to it. A stable climate is a global public good as it is something all of humanity enjoys. We all, to a greater or lesser extent, affect it too. It makes no difference if carbon dioxide is released in Beijing, Birmingham or Baltimore.</p>
<p>If the atmosphere is a global public good then, in the absence of <a href="https://theconversation.com/how-to-ensure-governments-stick-to-their-paris-climate-commitments-50354">enforcement via international law</a> to limit carbon emissions, you may conclude we are doomed. There is nothing to stop someone from emitting more than their fair share – this is the <a href="http://plato.stanford.edu/entries/free-rider">free rider problem</a>. </p>
<p>If enough people act selfishly (and much of economic theory begins with the assumption that humans are self-interested), then the Earth’s sinks for carbon pollution will be swamped and dangerous climate change will ensue. This would be an example of a <a href="https://www.sciencemag.org/content/162/3859/1243.full">tragedy of the commons</a> which has become an influential feature of western economic thinking since the latter half of the 20th century. However, the situation is perhaps not quite so clear cut.</p>
<h1>Can we avoid climate tragedy?</h1>
<p>In 2009, US political scientist Elinor Ostrom received the <a href="http://www.nobelprize.org/nobel_prizes/economic-sciences/laureates/2009/ostrom_lecture.pdf">Nobel Prize in Economic Sciences</a> for her work on the management of public goods and common-pool resources. What Ostrom established is that, contrary to certain grim predictions, there are numerous examples of effectively managed public goods: Nepalese forests, American lobster fisheries, community irrigation schemes in Spain and many other systems are looked after sustainably through following a combination of <a href="http://www.onthecommons.org/magazine/elinor-ostroms-8-principles-managing-commmons">eight principles</a>.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/103218/original/image-20151125-23825-1ll5ol4.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/103218/original/image-20151125-23825-1ll5ol4.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/103218/original/image-20151125-23825-1ll5ol4.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=686&fit=crop&dpr=1 600w, https://images.theconversation.com/files/103218/original/image-20151125-23825-1ll5ol4.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=686&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/103218/original/image-20151125-23825-1ll5ol4.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=686&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/103218/original/image-20151125-23825-1ll5ol4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=862&fit=crop&dpr=1 754w, https://images.theconversation.com/files/103218/original/image-20151125-23825-1ll5ol4.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=862&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/103218/original/image-20151125-23825-1ll5ol4.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=862&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"></span>
<span class="attribution"><a class="source" href="http://www.onthecommons.org/magazine/elinor-ostroms-8-principles-managing-commmons">Elinor Ostrom</a></span>
</figcaption>
</figure>
<p>The implications are profound. Rather than assume the market or central control are the most effective mechanisms to manage goods and services, Ostrom showed that groups of people can self-organise around common interests. </p>
<p>But it hasn’t escaped the attention of those trying to get international agreement on greenhouse gas emissions that some of these principles will not apply. In fact, if you are feeling particularly pessimistic, these principles can almost serve as a checklist of why such agreement will prove impossible. National boundaries do not stop the circulation of atmospheric gases, for instance, and there is no international body to police and enforce carbon emissions. </p>
<h1>Global concerns, local action</h1>
<p>So it seems all the more remarkable that agreements to limit carbon emissions and even reduce them from the atmosphere have been achieved. What’s more, these agreements are popping up all over the place. More than <a href="http://www.c40.org">80 major cities</a> across the globe are currently coordinating climate action. There are now a number of <a href="http://www.wci-inc.org/">carbon trading communities</a> that encompass a <a href="http://www.rggi.org">range of states</a> in North America. EU member nations have agreed <a href="http://ec.europa.eu/clima/policies/strategies/2030/index_en.htm">binding reductions</a> while earlier this year the two largest emitters of carbon dioxide, the US and China, established important <a href="https://www.whitehouse.gov/the-press-office/2015/09/25/us-china-joint-presidential-statement-climate-change">bilateral commitments</a> to control carbon emissions in their respective countries. </p>
<p>These are all examples of <a href="http://www.icpublicpolicy.org/IMG/pdf/panel_46_s1_araral_hartley.pdf">polycentric governance</a>. Having multiple levels of organisation allows flexibility and effective <a href="http://www.inogov.eu/wp-content/uploads/2015/11/INOGOV-Policy-Brief-No1-November-2015-Governing-the-EU-2030-renewables-target.pdf">regional solutions</a> to some of the obstacles that large, rigid governance can produce. </p>
<p>Are such efforts sufficient to avoid dangerous climate change? No. Nor are the <a href="http://cait.wri.org/indc/">national commitments to reduce emissions</a> ahead of Paris. But what these regional initiatives show is that local communities can act independently of international agreements by making a global public good a local concern.</p>
<p>This may still seem puzzling to some economists and political scientists. While some of these initiatives make economic sense, what is the good of unilaterally self-imposed emissions limits if other regions don’t play ball? The answer to this question not only points the way to more effective action, but highlights a gaping hole in some people’s and institutions’ understanding of climate change: it’s the right thing to do. </p>
<p>Climate change is as much a moral issue as a scientific one. Taking more than your fair share is wrong. Changing the climate which leads to people being harmed is wrong. </p>
<p>Any effective agreement that emerges from Paris will not have come out of a vacuum, but as a consequence of many individuals’ and communities’ agitation for change – some <a href="http://www.dangerousideassouthampton.org.uk">locally</a>, some <a href="http://350.org/">through the internet</a>. </p>
<p>If we are going to address climate change, then recognising our shared values and interests is crucial. Humans are fundamentally a social species. We’ve only very recently appreciated that we are also a <a href="http://quaternary.stratigraphy.org/workinggroups/anthropocene">planet-altering species</a>. Our moral senses know intuitively what we need to do in the light of such knowledge. Our economic and political institutions need to catch up rapidly.</p><img src="https://counter.theconversation.com/content/50687/count.gif" alt="The Conversation" width="1" height="1" />
Success in dealing with common resources on a smaller scale proves it’s not impossible to manage the biggest common resource of all – planet Earth.James Dyke, Lecturer in Complex Systems Simulation, University of SouthamptonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/469142015-09-02T17:01:31Z2015-09-02T17:01:31ZThree trillion trees live on Earth, but there would be twice as many without humans<figure><img src="https://images.theconversation.com/files/93643/original/image-20150902-6192-1stfc6d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption"></span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/25183035@N03/7248005726/">JD Rucker</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Each year, humans reduce the number of trees worldwide by 15 billion. This is one of the startling conclusions of new research published in the journal <a href="http://nature.com/articles/doi:10.1038/nature14967">Nature</a>. The study also estimates the Earth is home to more than three trillion trees – that’s 3,000 billion – so you may think that while 15 billion is a very large number, humans shouldn’t be at risk of making significant changes to global tree cover.</p>
<p>However, the team of 31 international scientists led by <a href="http://climate.yale.edu/people/thomas-crowther">Thomas Crowther</a> at Yale University also present evidence that the rise of human civilisation has reduced the numbers of trees on Earth by 46%. In many areas we can’t see the wood because there are no trees. Unlike polar bears, pandas or peregrine falcons, trees and their demise typically do not generate much passion or protest. But the 180,000km<sup>2</sup> of tree cover being <a href="http://www.theguardian.com/environment/2015/sep/02/trees-covering-an-area-twice-the-size-of-portugal-lost-in-2014-study-finds">lost each year</a> represents a serious destabilising force on the current biosphere. </p>
<p>Previous estimates for the total number of trees on Earth have been <a href="http://www.npr.org/templates/story/story.php?storyId=96758439">much lower</a>. The new study is important not only because it gives a higher number, but how it was produced. As well as using remote sensing data such as images taken by satellites that can classify land type, the research also integrated 429,775 ground-based assessments of tree density. </p>
<p>The researchers used this information to build a series of mathematical models which can fill in any gaps in the data with robust estimates. This allowed them to produce the first continuous map of global tree densities at the one square kilometre scale. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/93641/original/image-20150902-6179-2chdpr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/93641/original/image-20150902-6179-2chdpr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/93641/original/image-20150902-6179-2chdpr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=251&fit=crop&dpr=1 600w, https://images.theconversation.com/files/93641/original/image-20150902-6179-2chdpr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=251&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/93641/original/image-20150902-6179-2chdpr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=251&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/93641/original/image-20150902-6179-2chdpr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=316&fit=crop&dpr=1 754w, https://images.theconversation.com/files/93641/original/image-20150902-6179-2chdpr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=316&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/93641/original/image-20150902-6179-2chdpr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=316&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Three trillion trees, mapped to the square kilometre.</span>
<span class="attribution"><a class="source" href="http://nature.com/articles/doi:10.1038/nature14967">Crowther et al / Nature</a></span>
</figcaption>
</figure>
<p>Humans have long used trees as fuel for cooking or smelting, fibres for clothes, timber for construction. However it is the indirect value of trees that may prove to be more important. </p>
<p>A solitary tree can provide a habitat to myriad species in its leaves, branches, bark and roots. But it is the effects <a href="http://www.researchgate.net/profile/Clive_Jones4/publication/258223063_Organisms_as_Ecosystem_Engineers._Oikos_69_373-386/links/00463527d9b59e7165000000.pdf">trees have on their environments</a> that can affect life across entire landscapes. When alive, trees can stabilise slopes and the course of rivers and streams. When dead their wood debris can form dams and so create ponds and lakes. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/93642/original/image-20150902-6163-1gcdqn0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/93642/original/image-20150902-6163-1gcdqn0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/93642/original/image-20150902-6163-1gcdqn0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=771&fit=crop&dpr=1 600w, https://images.theconversation.com/files/93642/original/image-20150902-6163-1gcdqn0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=771&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/93642/original/image-20150902-6163-1gcdqn0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=771&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/93642/original/image-20150902-6163-1gcdqn0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=969&fit=crop&dpr=1 754w, https://images.theconversation.com/files/93642/original/image-20150902-6163-1gcdqn0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=969&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/93642/original/image-20150902-6163-1gcdqn0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=969&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Clouds are spread evenly over the Amazon rainforest – but avoid the river and its floodplain.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Transpiration#/media/File:Afternoon_Clouds_over_the_Amazon_Rainforest.jpg">NASA</a></span>
</figcaption>
</figure>
<p>As well as changing water on the ground, they can alter it in the air. Transpiration is the name given to the process whereby trees (and other plants) suck up water through their roots, transport it through trunks and branches leaving the tree through tiny holes called stoma in their leaves. Stoma are crucial as they allow carbon dioxide to be absorbed, which along with water and sunlight are the ingredients with which all trees produce their food. </p>
<p>Only a fraction of the water absorbed is consumed during photosynthesis, with the rest evaporating out from leaf stoma. This means some trees act as massive humidifiers. Through sucking up water held in soil and releasing it tens of meters above the ground, forests can be effective cloud machines as that water vapour rises and then condenses. This is one of the reasons <a href="https://www.youtube.com/watch?v=Y3OWgb0Bv-A">why it rains in the rainforest</a>.</p>
<h2>Global impacts of tree loss</h2>
<p>As well as changing local weather, large forests can affect the global climate. Through the burning of fossil fuels, humans release <a href="http://www.eia.gov/cfapps/ipdbproject/iedindex3.cfm?tid=90&pid=44&aid=8&cid=regions&syid=2012&eyid=2012&unit=MMTCD">approximately 32 billion tons of carbon dioxide</a> into the atmosphere, each year. Higher concentrations of CO<sub>2</sub> in the air can lead to faster rates of photosynthesis and more vigorous tree and plant growth, a process termed <a href="http://www.fao.org/docrep/w5183e/w5183e06.htm">carbon fertilisation</a>. This draws some of this additional carbon dioxide back down from the atmosphere. The Amazon rainforest alone absorbs approximately two billion tons of extra carbon dioxide each year. Within its leaves, branches, trunks and roots lies more than a hundred billion metric tonnes of carbon. Thus the Amazon rainforest has served as an important counter to anthropogenic climate change. </p>
<p>Rather worryingly, it appears as if the Amazon’s ability to soak up excessive carbon dioxide is <a href="https://theconversation.com/amazon-carbon-sink-is-in-decline-as-trees-die-off-faster-38946">grinding to a halt</a>. Faster tree growth has been accompanied with higher mortality. Trees that live fast die young. As climate change progresses, mortality rates are predicted to <a href="http://www.sciencedirect.com/science/article/pii/S037811270900615X">climb higher</a> largely as consequence of extreme weather events such as droughts. A world that continues to warm is one which could see a significantly reduced Amazon rain forest. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/93679/original/image-20150902-14067-16h9vgc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/93679/original/image-20150902-14067-16h9vgc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/93679/original/image-20150902-14067-16h9vgc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/93679/original/image-20150902-14067-16h9vgc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/93679/original/image-20150902-14067-16h9vgc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/93679/original/image-20150902-14067-16h9vgc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/93679/original/image-20150902-14067-16h9vgc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/93679/original/image-20150902-14067-16h9vgc.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">Clouds of a different kind cover the Amazon – smoke from ‘slash and burn’ forest clearing.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/nasaearthobservatory/6283416535/i">NASA</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The die-back of the Amazon has been identified as a potential <a href="http://www.pnas.org/content/105/6/1786.short">global tipping point</a>. There are good reasons to think that the Amazon rainforest, if sufficiently stressed by climate change could rapidly collapse and be replaced by savannah-type vegetation or even desert. After all, less than 10,000 years ago the Sahara was <a href="http://news.nationalgeographic.com/news/2008/05/080508-green-sahara.html">lush and well populated</a>. Any appreciable dieback of the Amazon would lead to many billions of tons of carbon dioxide being added to the atmosphere as the carbon previously locked up in tree biomass is released as dead wood decomposes. </p>
<p>The Amazon drought of 2010 greatly increased tree mortality with the result that more than <a href="https://www.sciencemag.org/content/331/6017/554.short?related-urls=yes&legid=sci;331/6017/554">two billion tons of carbon dioxide</a> was emitted into the Earth’s atmosphere (that’s four times as much as the UK’s contribution in 2012). Over mere decades the Amazon could turn from a large sink of carbon to a large source, further amplifying climate change. </p>
<p>A sensible course of action when dealing with this potential carbon bomb would be to reduce our emissions of greenhouse gasses and manage the forest on the ground as best we can. Instead emissions continue to rise while we hit the unexploded ordinance with a hammer. Or rather a chainsaw. </p>
<p>Trees in the Amazon continue to be felled. Humans are attacking the forest on two fronts: a local front that follows new roads which open up previously undisturbed forest to logging, and a global front through emissions of greenhouse gasses from industrialised nations. The two will interact which could significantly <a href="http://www.pnas.org/content/106/49/20610.short">increase the risk of widespread die back</a> of the Amazon. </p>
<p>The new research published in Nature will help improve our understanding of the role trees play in ecological and biogeochemical processes not just in the Amazon but across the globe. This knowledge could help inform management practices for the remaining forests. But perhaps its greatest impact will be the realisation that the emergence of civilisation has led to the net destruction of nearly three trillion of Earth’s trees. That could serve as a powerful perspective for comprehending the impacts humans have had on the natural world.</p><img src="https://counter.theconversation.com/content/46914/count.gif" alt="The Conversation" width="1" height="1" />
Each year more than 15 billion trees are lost worldwide, according to a major new study.James Dyke, Lecturer in Complex Systems Simulation, University of SouthamptonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/433472015-08-12T09:07:55Z2015-08-12T09:07:55ZCan the Earth feed 11 billion people? Four reasons to fear a Malthusian future<p>Humanity is on course for a population greater than 11 billion by the end of this century, according to the <a href="http://www.amstat.org/meetings/jsm/2015/onlineprogram/AbstractDetails.cfm?abstractid=317963">latest analysis</a> from the UN’s population division.</p>
<p>In a simple sense, population is the root cause of all sustainability issues. Clearly if there were no humans there would be no human impacts. Assuming you don’t wish to see the complete end of the human race – a desire that is shared by some <a href="http://www.cbc.ca/news/technology/vhemt-the-case-against-humans-1.742788">deep green thinkers</a> and [Bond super-villians](http://jamesbond.wikia.com/wiki/Hugo_Drax_(Michael_Lonsdale) – then the issue is whether there is an optimal number of humans on the planet.</p>
<p>Discussions on population growth often start with the work of Rev Thomas Robert Malthus whose <a href="http://www.gutenberg.org/files/4239/4239-h/4239-h.htm">An Essay on the Principle of Population</a> published at the end of the 18th century is one of the seminal works of demography. Populations change in response to three driving factors: fertility – how many people are born; mortality – how many people die; and migration – how many people leave or enter the population. </p>
<p>Malthus observed that more births than deaths would lead to exponential growth which would always outpace any improvements in farming and increases in yields. Consequently, unchecked growth was doomed to end in famine and population collapse. Malthus was right about exponential growth, but he was <a href="http://www.economist.com/node/11374623">famously wrong</a> about his dire predictions for the consequences of such growth. </p>
<p>At a global level we can ignore migration (no interplanetary migration happening just yet) and so the tremendous rise in the total numbers of humans is a result of an imbalance between fertility and mortality rates.</p>
<p>Over longer timescales, the recent increases look practically vertiginous. We seem to be on a trajectory that would surely exceed whatever the <a href="https://na.unep.net/geas/archive/pdfs/GEAS_Jun_12_Carrying_Capacity.pdf">carrying capacity</a> of the Earth is. However, 11 billion could be the high water mark as the UN forecasts population to slowly decrease after the end of this century.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/91297/original/image-20150810-11085-ngrlhr.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/91297/original/image-20150810-11085-ngrlhr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/91297/original/image-20150810-11085-ngrlhr.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=354&fit=crop&dpr=1 600w, https://images.theconversation.com/files/91297/original/image-20150810-11085-ngrlhr.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=354&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/91297/original/image-20150810-11085-ngrlhr.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=354&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/91297/original/image-20150810-11085-ngrlhr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=445&fit=crop&dpr=1 754w, https://images.theconversation.com/files/91297/original/image-20150810-11085-ngrlhr.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=445&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/91297/original/image-20150810-11085-ngrlhr.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=445&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Whatever sustainability looks like, it’s not this.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/File:Population_curve.svg">El T / census.gov</a></span>
</figcaption>
</figure>
<p>This brings us to Malthus’ first error: he wasn’t able to appreciate that the process of industrialisation and development that decreased mortality rates would, in time, decrease fertility rates too. Higher living standards associated with better education, in particular <a href="http://www.earth-policy.org/data_highlights/2011/highlights13">female education and empowerment</a>, seem to lead to smaller family sizes – a <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2781829/">demographic transition</a> that has played out with some variations across most of the countries around the world. </p>
<p>This may explain how populations can overcome unsustainable growth, but it still seems remarkable that the Earth can provide for a 700% increase in the numbers of humans over the span of less than a few centuries. This was Malthus’s second error. He simply couldn’t conceive of the <a href="http://www.nature.com/nature/journal/v418/n6898/full/nature01013.html">tremendous increases in yields</a> that industrialisation produced. </p>
<h2>How we fed seven billion</h2>
<p>The “green revolution” that produced a four-fold increase in global food productivity since the middle of the 20th century relied on irrigation, pesticides and fertilisers. </p>
<p>You may describe yourself as an omnivore, vegetarian, or vegan – but in an sense we all eat fossilised carbon. This is because most fertiliser is produced through the <a href="https://theconversation.com/five-chemistry-inventions-that-enabled-the-modern-world-42452">Haber process</a> which creates ammonia (a fertiliser) by reacting atmospheric nitrogen with hydrogen under high temperatures and pressures. All that heat requires serious amounts of energy, and the hydrogen is derived from natural gas, which currently means the Haber process uses lots of fossil fuels. If we include production, processing, packaging, transportation, marketing and consumption, then the food system consumes <a href="http://www.fao.org/news/story/en/item/95161/icode/">more than 30% of total energy use</a>
while contributing 20% to global greenhouse gas emissions.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/91333/original/image-20150810-11068-1xnnzz4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/91333/original/image-20150810-11068-1xnnzz4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=315&fit=crop&dpr=1 600w, https://images.theconversation.com/files/91333/original/image-20150810-11068-1xnnzz4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=315&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/91333/original/image-20150810-11068-1xnnzz4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=315&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/91333/original/image-20150810-11068-1xnnzz4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=396&fit=crop&dpr=1 754w, https://images.theconversation.com/files/91333/original/image-20150810-11068-1xnnzz4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=396&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/91333/original/image-20150810-11068-1xnnzz4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=396&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">All this, just to grow some plants? Billingham is one of the UK’s largest fertiliser factories.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Billingham_ICI_plant_September_1970_No._7_geograph-3436065-by-Ben-Brooksbank.jpg">Ben Brooksbank</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Feeding the next four billion</h2>
<p>If industrialised agriculture can now feed seven billion, then why can’t we figure out how to feed 11 billion by the end of this century? There may be many issues that need to be addressed, the argument runs, but famine isn’t one of them. However there are a number of potentially unpleasant problems with this prognosis.</p>
<p>First, some research suggests <a href="http://www.nature.com/ncomms/journal/v3/n12/full/ncomms2296.html">global food production is stagnating</a>. The green revolution hasn’t run out of steam just yet but innovations such as GM crops, more efficient irrigation and <a href="http://www.telegraph.co.uk/news/earth/agriculture/farming/11706406/Londons-first-underground-farm-opens-in-WW2-air-raid-shelter.html">subterranean farming</a> aren’t going to have a big enough impact. The low-hanging fruits of yield improvements have already been gobbled up.</p>
<p>Second, the current high yields assume plentiful and cheap supplies of phosphorus, nitrogen and fossil fuels – mainly oil and gas. Mineral phosphorus isn’t going to run out anytime soon, nor will oil, but both are becoming increasingly <a href="https://theconversation.com/peak-phosphorus-will-be-a-shortage-we-cant-stomach-25065">harder to obtain</a>. All things being equal this will make them more expensive. The <a href="http://www.nytimes.com/2008/04/10/opinion/10thu1.html?_r=0">chaos in the world food systems</a> in 2007-8 gives some indication of the impact of higher food prices.</p>
<p>Third, soil is running out. Or rather it is running away. Intensive agriculture which plants crops on fields without respite leads to <a href="https://www.worldwildlife.org/threats/soil-erosion-and-degradation">soil erosion</a>. This can be offset by using more fertiliser, but there comes a point where the soil is so eroded that farming there becomes very limited, and it will take many years for such soils to recover.</p>
<p>Fourth, it is not even certain we will be able to maintain yields in a world that is facing potentially significant environmental change. We are on course towards 2°C of warming by the end of this century. Just when we have the greatest numbers of people to feed, floods, storms, droughts and other extreme weather will cause significant disruption to food production. In order to avoid dangerous climate change, we must keep the majority of the Earth’s fossil fuel deposits <a href="http://www.nature.com/nature/journal/v517/n7533/full/nature14016.html">in the ground</a> – the same fossil fuels that our food production system has become effectively addicted to.</p>
<p>If humanity is to have a long-term future, we must address all these challenges at the same time as reducing our impacts on the planetary processes that ultimately provide not just the food we eat, but water we drink and air we breathe. This is a challenge far greater than those that so exercised Malthus 200 years ago.</p><img src="https://counter.theconversation.com/content/43347/count.gif" alt="The Conversation" width="1" height="1" />
Humanity is on course for a population greater than 11 billion by the end of this century, according to the latest analysis from the UN’s population division. In a simple sense, population is the root…James Dyke, Lecturer in Complex Systems Simulation, University of SouthamptonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/434322015-06-19T18:25:11Z2015-06-19T18:25:11ZEarth’s sixth mass extinction has begun, new study confirms<figure><img src="https://images.theconversation.com/files/85718/original/image-20150619-3363-gjxzr7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">How long before the rhino joins the list?</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/zambog/15965594976/">Gerry Zambonini</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>We are currently witnessing the start of a mass extinction event the likes of which have not been seen on Earth for at least 65 million years. This is the alarming finding of a new study published in the journal <a href="http://advances.sciencemag.org/content/1/5/e1400253">Science Advances</a>. </p>
<p>The research was designed to determine how human actions over the past 500 years have affected the extinction rates of vertebrates: mammals, fish, birds, reptiles and amphibians. It found a clear signal of elevated species loss which has markedly accelerated over the past couple of hundred years, such that life on Earth is embarking on its sixth greatest extinction event in its 3.5 billion year history. </p>
<p>This latest research was conducted by an international team lead by <a href="http://web.ecologia.unam.mx/personal/personal_perfil.php?var1=Dr.&var2=Gerardo&var3=Ceballos&var4=Gonz%C3%A1lez">Gerardo Ceballos</a> of the National Autonomous University of Mexico. Measuring extinction rates is notoriously hard. Recently <a href="https://theconversation.com/one-in-six-species-faces-extinction-as-a-result-of-climate-change-41018">I reported</a> on some of the fiendishly clever ways such rates have been estimated. These studies are producing <a href="https://theconversation.com/we-can-avoid-mass-extinction-but-time-is-running-out-32441">profoundly worrying results</a>.</p>
<p>However, there is always the risk that such work overestimates modern extinction rates because they need to make a number of assumptions given the very limited data available. Ceballos and his team wanted to put a floor on these numbers, to establish extinction rates for species that were very conservative, with the understanding that whatever the rate of species lost has actually been, it could not be any lower. </p>
<p>This makes their findings even more significant because even with such conservative estimates they find extinction rates are much, much higher than the background rate of extinction – the rate of species loss in the absence of any human impacts.</p>
<p>Here again, they err on the side of caution. A number of studies have attempted to estimate the background rate of extinction. These have produced upper values of about one out of every million species being lost each year. Using <a href="http://www.ncbi.nlm.nih.gov/pubmed/21368823">recent work</a> by co-author Anthony Barnosky, they effectively double this background rate and so assume that two out of every million species will disappear through natural causes each year. This should mean that differences between the background and human driven extinction rates will be smaller. But they find that the magnitude of more recent extinctions is so great as to effectively swamp any natural processes. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/85760/original/image-20150619-3347-1btwpy0.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/85760/original/image-20150619-3347-1btwpy0.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/85760/original/image-20150619-3347-1btwpy0.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=441&fit=crop&dpr=1 600w, https://images.theconversation.com/files/85760/original/image-20150619-3347-1btwpy0.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=441&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/85760/original/image-20150619-3347-1btwpy0.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=441&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/85760/original/image-20150619-3347-1btwpy0.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=554&fit=crop&dpr=1 754w, https://images.theconversation.com/files/85760/original/image-20150619-3347-1btwpy0.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=554&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/85760/original/image-20150619-3347-1btwpy0.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=554&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Cumulative vertebrate species recorded as extinct or extinct in the wild by the IUCN (2012). Dashed black line represents background rate. This is the ‘highly conservative estimate’.</span>
<span class="attribution"><a class="source" href="http://advances.sciencemag.org/content/1/5/e1400253">Ceballos et al</a></span>
</figcaption>
</figure>
<p>The “very conservative estimate” of species loss uses International Union of Conservation of Nature data. This contains documented examples of species becoming extinct. They use the same data source to produce the “conservative estimate” which includes known extinct species and those species believed to be extinct or extinct in the wild.</p>
<p>The paper has been published in an open access journal and I would recommend reading it and the accompanying Supplementary Materials. This includes the list of vertebrate species known to have disappeared since the year 1500. The Latin names for these species would be familiar only to specialists, but even the common names are exotic and strange: the Cuban coney, red-bellied gracile, broad-faced potoroo and southern gastric brooding frog. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/85766/original/image-20150619-3353-1q4zyn4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/85766/original/image-20150619-3353-1q4zyn4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=388&fit=crop&dpr=1 600w, https://images.theconversation.com/files/85766/original/image-20150619-3353-1q4zyn4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=388&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/85766/original/image-20150619-3353-1q4zyn4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=388&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/85766/original/image-20150619-3353-1q4zyn4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=488&fit=crop&dpr=1 754w, https://images.theconversation.com/files/85766/original/image-20150619-3353-1q4zyn4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=488&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/85766/original/image-20150619-3353-1q4zyn4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=488&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Farewell, broad-faced potoroo, we hardly knew ye.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/File:BroadFacedPotoroo.jpg">John Gould</a></span>
</figcaption>
</figure>
<p>These particular outer branches of the great tree of life now stop. Some of their remains will be preserved, either as fossils in layers of rocks or glass eyed exhibits in museum cabinets. But the Earth will no longer see them scurry or soar, hear them croak or chirp. </p>
<p>You may wonder to what extent does this matter? Why should we worry if the natural process of extinction is amplified by humans and our expanding industrialised civilisation?</p>
<p>One response to this question essentially points out what the natural world does for us. Whether it’s pollinating our crops, purifying our water, providing fish to eat or fibres to weave, <a href="http://www.nature.com/nature/journal/v486/n7401/full/nature11148.html">we are dependent on biodiveristy</a>. Ecosystems can only continue to provide things for us if they continue to function in approximately the same way. </p>
<p>The relationship between species diversity and ecosystem function is very complex and not well understood. There may be gradual and reversible decreases in function with decreased biodiversity. There may be effectively no change until a tipping point occurs. The analogy here is <a href="http://web.clark.edu/smethvin/classes_pdf/Basics/gen_sociology_101/handouts/Unit4/Rivet%20Poppers.pdf">popping out rivets</a> from a plane’s wing. The aircraft will fly unimpaired if a few rivets are removed here or there, but to continue to remove rivets is to move the system closer to catastrophic failure. </p>
<p>This latest research tells us what we already knew. Humans have in the space of a few centuries swung a wrecking ball through the Earth’s biosphere. Liquidating biodiversity to produce products and services has an end point. Science is starting to sketch out <a href="https://theconversation.com/humanity-is-in-the-existential-danger-zone-study-confirms-36307">what that end point could look like</a> but it cannot tell us why to stop before we reach it.</p>
<p>If we regard the Earth as nothing more than a source of resources and a sink for our pollution, if we value other species only in terms of what they can provide to us, then we we will continue to unpick the fabric of life. Remove further rivets from spaceship earth. This not only increases the risk that it will cease to function in the ways that we and future generations will depend on, but can only reduce the complexity and beauty of our home in the cosmos.</p><img src="https://counter.theconversation.com/content/43432/count.gif" alt="The Conversation" width="1" height="1" />
Even if humans survive the planet will never be the same again.James Dyke, Lecturer in Complex Systems Simulation, University of SouthamptonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/427002015-06-03T15:05:14Z2015-06-03T15:05:14Z‘Global Apollo’ programme for renewables cannot take off without political power<figure><img src="https://images.theconversation.com/files/83793/original/image-20150603-10695-kmd6l9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">It always seems impossible until it's done.</span> <span class="attribution"><span class="source">NASA</span></span></figcaption></figure><p>A group of prominent scientists has launched an “Apollo programme” for renewables, called <a href="http://www.globalapolloprogramme.org/">Global Apollo</a>. Its mission is to make carbon-free electricity less costly than that generated from coal, and to do it within ten years. It’s an international effort that will promote the technological advances required to produce the rapid transition from fossil fuels to renewable energy, and so keep climate change to within the “safe” limit of two degrees celsius. </p>
<p>It’s an ambitious if not audacious statement of intent that will seek to marshal the efforts of current and new generations of engineers and scientists.</p>
<p>And on its own it’s doomed to failure. Let me explain. </p>
<p>The Global Apollo mission takes inspiration not only from the <a href="http://www.nasa.gov/mission_pages/apollo/missions/index.html">Apollo Program</a> that sent humans to the moon, but also the <a href="http://www.itrs.net/">International Technology Roadmap for Semiconductors</a> (ITRS). What’s that got to do with climate change? Well, the ITRS is a collaborative effort between the world’s largest chip manufacturers to understand, plan and ultimately resolve technological challenges that allow faster semiconductor chips. Over the past 30 years this has produced continual decreases in microchip prices along with steady performance improvements. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/83806/original/image-20150603-2943-it3a5c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/83806/original/image-20150603-2943-it3a5c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/83806/original/image-20150603-2943-it3a5c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=846&fit=crop&dpr=1 600w, https://images.theconversation.com/files/83806/original/image-20150603-2943-it3a5c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=846&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/83806/original/image-20150603-2943-it3a5c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=846&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/83806/original/image-20150603-2943-it3a5c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1064&fit=crop&dpr=1 754w, https://images.theconversation.com/files/83806/original/image-20150603-2943-it3a5c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1064&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/83806/original/image-20150603-2943-it3a5c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1064&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">By the 60s semiconductors were taking over from vacuum tubes.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/91591049@N00/14672175040/in/">SenseiAlan</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Faster and cheaper chips translates to better and cheaper electronic products that spur further innovation. It’s a win-win. But this is a terrible analogy for our current dependence on fossil fuels.</p>
<p>It’s a terrible analogy because the ITRS doesn’t operate in a world in which electronic <a href="http://www.vacuumtubes.net/How_Vacuum_Tubes_Work.htm">vacuum tube</a> manufacturers spend <a href="http://www.washingtonpost.com/politics/fossil-fuel-lobbyists-bolstered-by-gop-wins-work-to-curb-environmental-rules/2014/12/07/3ef05bc0-79b9-11e4-9a27-6fdbc612bff8_story.html">millions of dollars actively trying to undermine</a> the development of semiconductors. </p>
<h2>What renewables are up against</h2>
<p>Take Shell, for instance, which has been particularly belligerent on exploiting its fossil fuel reserves. Speaking last month, the company’s CEO <a href="http://www.theguardian.com/business/2015/may/22/shell-boss-endorses-warnings-about-fossil-fuels-and-climate-change">Ben van Beurden said</a>:</p>
<blockquote>
<p>All the oil that we have, we will use … There will still be a need for hydrocarbons for years to come, and the decline in existing production is always going to be faster than the decline that the most successful [low carbon] policies can create. There is always going to be a need for investment.</p>
</blockquote>
<p>This explains why Shell’s drilling platform <a href="http://www.rigzone.com/data/offshore_drilling_rigs/1095/Semisub/Transocean_Ltd/Transocean_Polar_Pioneer">Polar Explorer</a> is currently parked in Seattle, before heading north in the summer to start <a href="http://abcnews.go.com/US/wireStory/groups-sue-agency-block-shells-arctic-offshore-drilling-31476918">developing new fields in the Arctic</a>. That climate change is producing warmer temperatures in the Arctic and so reduced summer ice, which makes it easier to drill for more climate-changing fossil fuels, is either fortuitous or tragically ironic depending on your point of view.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/83808/original/image-20150603-2923-108we4d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/83808/original/image-20150603-2923-108we4d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/83808/original/image-20150603-2923-108we4d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=285&fit=crop&dpr=1 600w, https://images.theconversation.com/files/83808/original/image-20150603-2923-108we4d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=285&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/83808/original/image-20150603-2923-108we4d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=285&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/83808/original/image-20150603-2923-108we4d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=358&fit=crop&dpr=1 754w, https://images.theconversation.com/files/83808/original/image-20150603-2923-108we4d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=358&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/83808/original/image-20150603-2923-108we4d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=358&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Polar Explorer is met by anti-fossil fuel ‘kayaktivists’.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/backbone_campaign/17269233846/">Backbone Campaign</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>We have a good idea of how much carbon <a href="http://www.nature.com/nature/journal/v517/n7533/full/nature14016.html">we need to leave in the ground</a> and it’s more than current known reserves. We don’t need to be prospecting for more fossil fuels. Shell attempts to avoid the conclusions of its behaviour by arguing for <a href="http://www.ccsassociation.org/what-is-ccs/">carbon capture and storage</a> – removing the carbon dioxide from the point of pollution, or some other technologies that could scrub it out of the atmosphere. </p>
<p>However, given <a href="https://mitei.mit.edu/news/we-did-math-clean-coal-and-it-doesnt-add">the feeble performance of carbon capture and storage</a> and the requirements for sustained decreases in greenhouse gas emissions right now, this is equivalent to identifying the hard-to-fix element of problem, drawing a box around it and labelling it “this is where the magic happens”. </p>
<p>Earlier this year environmental campaigner and consultant Jonathon Porritt <a href="http://www.theguardian.com/environment/2015/jan/15/it-is-impossible-todays-big-oil-companies-adapt-climate-change-jonathon-porritt">gave up working with Shell</a> and concluded that it and BP will never transition away from being companies built around the exploitation of fossil fuels. It’s hard not to come to the same conclusion. </p>
<p>You may accept all that, but still feel it doesn’t seem fair to argue that companies like Shell are trying to stop the development of renewable energy. Yet oil and gas firms account for five out of the world’s top six <a href="http://www.forbes.com/global2000/list/#header:revenue_sortreverse:true">companies by revenue</a>. There are tremendous amounts of money to be made from digging up fossilised carbon, and these firms are profiting hugely from the status quo.</p>
<p>These profits buy access to power. Recent <a href="http://www.theguardian.com/environment/2015/apr/28/fossil-fuel-lobby-given-far-more-access-to-uk-ministers-than-renewables-analysis">analysis from the Guardian</a> shows that between 2010 and 2015, Shell alone met with UK ministers at least 112 times. This was nearly as much as the total number of meetings from 23 renewable energy companies over the same period. </p>
<p>Maybe it’s just a coincidence that the recently passed <a href="http://services.parliament.uk/bills/2014-15/infrastructure.html">Infrastructure Act</a> includes the passage on “maximising economic recovery of petroleum in the United Kingdom”. This means the Secretary of State for Energy and Climate Change will in future be legally obliged to promote the extraction of fossil fuels, while also being legally obliged to reduce emissions as a consequence of the 2008 <a href="http://www.legislation.gov.uk/ukpga/2008/27/introduction">Climate Change Act</a>. Perhaps another magic trick is required?</p>
<p>Notwithstanding their very large revenues, oil and gas companies also receive extensive tax breaks and economic incentives to exploit more fossil fuels. The International Energy Authority estimated these were <a href="http://www.worldenergyoutlook.org/resources/energysubsidies/">US$548 billion in 2013</a>. </p>
<h2>The problems are political</h2>
<p>It is on this landscape that Global Apollo launches. It and similar endeavours such as the <a href="http://www.greattransition.org/publication/bounding-the-planetary-future-why-we-need-a-great-transition">Great Transition</a> are urgently needed, but they will only succeed with buy-in from all sectors of society. That involves the challenge of leaving potentially trillions of dollars in the ground and with it the influence and power that could wield. </p>
<p>Power does not evaporate in the face of compelling argument. Building a vision of low-carbon energy generation is necessary for a sustainable future. But it isn’t sufficient. The power that fossil fuel companies currently enjoy must be challenged. This will require a leap as great as any of the technical and engineering advances of Global Apollo or the original Apollo Program. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/83792/original/image-20150603-10676-1yolczr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/83792/original/image-20150603-10676-1yolczr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/83792/original/image-20150603-10676-1yolczr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=604&fit=crop&dpr=1 600w, https://images.theconversation.com/files/83792/original/image-20150603-10676-1yolczr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=604&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/83792/original/image-20150603-10676-1yolczr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=604&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/83792/original/image-20150603-10676-1yolczr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=759&fit=crop&dpr=1 754w, https://images.theconversation.com/files/83792/original/image-20150603-10676-1yolczr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=759&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/83792/original/image-20150603-10676-1yolczr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=759&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 footprint that will last millions of years. Global Apollo could have a much greater legacy.</span>
<span class="attribution"><span class="source">Edwin Aldrin, Apollo 11, NASA</span></span>
</figcaption>
</figure>
<p>If that happens, if we are able to rein in the power and influence of oil and gas companies at the same time as help them transform into providers of low carbon energy, then Global Apollo may just work and in doing so surpass a footprint made in lunar dust nearly 46 years ago.</p><img src="https://counter.theconversation.com/content/42700/count.gif" alt="The Conversation" width="1" height="1" />
There’s no point promoting renewable technology if all the power still resides with fossil fuel firms.James Dyke, Lecturer in Complex Systems Simulation, University of SouthamptonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/410182015-04-30T18:12:10Z2015-04-30T18:12:10ZOne in six species faces extinction as a result of climate change<figure><img src="https://images.theconversation.com/files/79975/original/image-20150430-30716-1irpmy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Can rhinos pray for rain?</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/baronreznik/15392149569">Baron Reznik</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span></figcaption></figure><p>The Earth is on course to lose up to one in six of all its species, if carbon emissions continue as they currently are. This global extinction risk masks very large regional variations. Up to a quarter of South American species may be doomed. </p>
<p>These are some of the findings of a comprehensive piece of new research conducted by evolutionary ecologist Mark Urban and published in <a href="http://www.sciencemag.org/lookup/doi/10.1126/science.aaa4984">Science</a>. </p>
<p>You may console yourself that these are the very upper estimates of some of the consequences of uncontrolled carbon emissions. We can’t really be facing such a collapse in biodiversity can we? What Urban establishes is that far from being fanciful, these estimates are in fact the results of very robust analysis. What’s more they could be worse. Much worse. </p>
<p>Assessing how many species have gone extinct due to human impacts is notoriously hard. Previously, I reported on a study published in Nature that estimated that over the past 500 years, <a href="https://theconversation.com/we-can-avoid-mass-extinction-but-time-is-running-out-32441">13% of all species</a> had been lost as a consequence of human behaviour. Urban’s study uses a similar approach in that he conducts a systematic review of published papers and builds a series of statistical models that synthesise the central findings. </p>
<p>Urban found that keeping emissions to within rates that would limit climate change to the “safe” amount of 2°C would lead to a little over 5% increase in total extinction risks. Business as usual carbon emissions would produce over 4°C warming and nearly 16% extinction. </p>
<p><strong>Extinction risks accelerate with global temperature rises:</strong></p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/79982/original/image-20150430-30735-13te1ap.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/79982/original/image-20150430-30735-13te1ap.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/79982/original/image-20150430-30735-13te1ap.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=518&fit=crop&dpr=1 600w, https://images.theconversation.com/files/79982/original/image-20150430-30735-13te1ap.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=518&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/79982/original/image-20150430-30735-13te1ap.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=518&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/79982/original/image-20150430-30735-13te1ap.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=651&fit=crop&dpr=1 754w, https://images.theconversation.com/files/79982/original/image-20150430-30735-13te1ap.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=651&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/79982/original/image-20150430-30735-13te1ap.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=651&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Extinction risks under current 0.8°C post-industrial rise; the 2°C policy target; and two IPCC scenarios.</span>
<span class="attribution"><span class="source">Urban/Science</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Urban also made the surprising discovery that the varying research methods employed didn’t matter – the different papers all pointed towards similar estimates of extinction risk. Studies that built statistical models that correlate environmental factors to the distribution and abundance of species, produced on average the same results as mechanistic or process-based models that simulate populations of species. Very different techniques were producing the same magnitudes of extinction risk. </p>
<p>However, there were some key factors in Urban’s analysis that were associated with large uncertainty. The biggest differences in extinction risk were associated with different carbon emissions scenarios. This will be largely up to us to determine – how much of the existing reserves of coal, oil and gas are we willing to burn off? The second most important factor was the extinction debt – the unavoidable extinction of species – as a consequence of habitat loss. </p>
<p>If a species of tree frog can only reproduce in a particular species of tree, then when the very last tree of that species is cut down, the frog is doomed to extinction. There is for that particular region an extinction debt: while we may see individuals of that tree frog species now, at some point in the future they will vanish. This is an example of 100% habitat loss required to produce extinction. But many species will become extinct some time before all their habitat is lost. Urban conducted analysis in which he assumed 100%, 95% and 80% of habitat loss was required before extinction. He found a three-fold increase in extinction risk from 100% to 80% habitat loss. </p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/79989/original/image-20150430-30698-1mcfu5h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/79989/original/image-20150430-30698-1mcfu5h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/79989/original/image-20150430-30698-1mcfu5h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=627&fit=crop&dpr=1 600w, https://images.theconversation.com/files/79989/original/image-20150430-30698-1mcfu5h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=627&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/79989/original/image-20150430-30698-1mcfu5h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=627&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/79989/original/image-20150430-30698-1mcfu5h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=788&fit=crop&dpr=1 754w, https://images.theconversation.com/files/79989/original/image-20150430-30698-1mcfu5h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=788&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/79989/original/image-20150430-30698-1mcfu5h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=788&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">No trees, no frogs.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/backpackerben/2410127726">Benedict Adam</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Another crucial factor will be how fast climate change occurs. As the Earth’s climate warms, and local conditions change, species will respond in essentially three ways. </p>
<p>First, if environmental change is very slow, then individuals that are better adapted to new conditions will progressively replace the previously dominant individuals. Slow, progressive climate change may <a href="https://theconversation.com/rapidly-evolving-lizards-show-how-some-creatures-can-adapt-to-beat-climate-change-31705">produce evolutionary change</a>.</p>
<p>Second, if the rate of change is faster than evolutionary processes, then species may be able to buffer an amount of environmental change. This buffering can come as a result of what scientists call “<a href="http://www.eeb.cornell.edu/agrawal/pdfs/whitman-and-agrawal-2009-Ch_1-Phenotypic-Plasticity-of-Insects.pdf">phenotype plasticity</a>”. Certain species can express different genes as a response to environmental change. This changes their phenotype – their physical bodies and behaviour – so that they are better adapted to new conditions. This is more often observed in immobile or stationary organisms such as plants that can express different genes in hotter or drier conditions.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/79988/original/image-20150430-30726-r0yw5k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/79988/original/image-20150430-30726-r0yw5k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/79988/original/image-20150430-30726-r0yw5k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/79988/original/image-20150430-30726-r0yw5k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/79988/original/image-20150430-30726-r0yw5k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/79988/original/image-20150430-30726-r0yw5k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/79988/original/image-20150430-30726-r0yw5k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/79988/original/image-20150430-30726-r0yw5k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The crystalline iceplant can switch between two different modes of photosynthesis as a response to drought.</span>
<span class="attribution"><a class="source" href="http://en.wikipedia.org/wiki/Mesembryanthemum_crystallinum#/media/File:Unk_desert_flower_2.jpg">yummifruitbat</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<p>Third, if climate change happens too fast for evolution or adaptation, mobile species may be able to escape extinction by dispersing to other more suitable habitats. In order for this to be possible, there must be some viable route. For plants that disperse seeds on the wind, this may not be such an issue. But for species that produce offspring next to or near them it is crucial. Tree frogs may be able to respond to warmer temperature by progressively moving higher up the side of a mountain, but in order for that to happen there must not be any barriers such as rivers in the way. </p>
<p>These barriers are not only rivers, but roads, towns, fields and other human-driven land use changes. A third of the Earth’s surface has been <a href="http://data.worldbank.org/indicator/AG.LND.AGRI.ZS/countries/1W?display=graph">converted to agriculture</a>, cities continue to expand and road and rail networks multiply. This means we are attacking biodiveristy on two fronts: locally through destroying and fragmenting habitat, and globally by affecting the climate.</p>
<p>Urban ends his Science paper by noting that in the early 1980s climatologists warned that the signal that humans were affecting the climate was coming across loud and clear. Events since then show that our civilisation has either not heard or headed that message. </p>
<p>We are now detecting species loss due to this climate change and the message from Urban’s and other studies is unambiguous. We must leave most of the Earth’s fossil fuel reserves in the ground if we are to avoid consigning a significant fraction of its species to extinction.</p><img src="https://counter.theconversation.com/content/41018/count.gif" alt="The Conversation" width="1" height="1" />
A major new study looks at the risk global warming poses to the world’s plants and animals – it’s not good news.James Dyke, Lecturer in Complex Systems Simulation, University of SouthamptonLicensed as Creative Commons – attribution, no derivatives.