tag:theconversation.com,2011:/uk/topics/tim-flannery-4474/articlesTim Flannery – The Conversation2023-09-04T02:35:55Ztag:theconversation.com,2011:article/2115062023-09-04T02:35:55Z2023-09-04T02:35:55ZHow diving as a boy took Tim Flannery on the trail of the megalodon in all its ‘terrifying glory’<figure><img src="https://images.theconversation.com/files/545437/original/file-20230830-39956-lsjhr9.jpg?ixlib=rb-1.1.0&rect=77%2C11%2C3886%2C1970&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Tim Flannery with a model set of jaws of a megalodon at the Australian Museum, and, on right, a megalodon tooth.</span> <span class="attribution"><span class="source">Photos: Text Publishing, Wikimedia Commons</span></span></figcaption></figure><p>With <a href="https://www.imdb.com/title/tt9224104/">Meg 2: The Trench</a> currently showing in cinemas – its eponymous star looking unhelpfully like an oversized great white shark – megalodons are having another pop cultural moment.</p>
<p>Cinema-goers may, justifiably, have questions about the accuracy of this latest representation of these prehistoric creatures. The good news is that Tim and Emma Flannery have written a book that will both thrill and inform such curious readers.</p>
<hr>
<p><em>Review: Big Meg: The Story of the Largest and Most Mysterious Predator that Ever Lived – Tim Flannery and Emma Flannery (Text Publishing)</em></p>
<hr>
<p>Megalodons had cartilaginous structures, rather than the bony skeletons of the dinosaurs. While dinosaurs roamed Earth during the Triassic, Jurassic and Cretaceous periods (from 252 million to 66 million years ago), it is believed the megalodon emerged a mere 23 million years ago. </p>
<p>Megalodons had big, serrated teeth that could cut through large marine animals. When they became extinct, about 3.6 million years ago, palaeontologists were left only with remnants of their toothy smile from which to unpick the story of these sharks.</p>
<p>A palaeontologist by training, Tim Flannery’s prolific literary output has contributed both to academic debate and general awareness-raising about the nature and needs of the planet we continue to dominate. In this latest book, he has combined forces with his daughter, Emma, a scientist and explorer in her own right, but this is very much his story.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/544912/original/file-20230828-201730-am7gat.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/544912/original/file-20230828-201730-am7gat.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/544912/original/file-20230828-201730-am7gat.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=918&fit=crop&dpr=1 600w, https://images.theconversation.com/files/544912/original/file-20230828-201730-am7gat.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=918&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/544912/original/file-20230828-201730-am7gat.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=918&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/544912/original/file-20230828-201730-am7gat.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1153&fit=crop&dpr=1 754w, https://images.theconversation.com/files/544912/original/file-20230828-201730-am7gat.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1153&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/544912/original/file-20230828-201730-am7gat.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1153&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>
</figcaption>
</figure>
<p>Text Publishing’s edition advertises Big Meg as: “The Story of the Largest and Most Mysterious Predator that Ever Lived”. While these words are intended to excite readers, scientists have not yet assigned a definitive shape or weight to the megalodon. How sure can we be that it was the largest predator? <a href="https://en.wikipedia.org/wiki/Livyatan">Livyatan</a>, for instance, a prehistoric sperm whale, was an estimated 17.5m long and sported the largest teeth of any known creature. </p>
<p>At any rate, Tim and Emma Flannery approach the mysterious megalodon with imagination and intelligent speculation. They draw on what is already known of other species of sharks, while accepting this one could have been quite different.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/ancient-megalodon-super-predators-could-swallow-a-great-white-shark-whole-new-model-reveals-188749">Ancient megalodon super-predators could swallow a great white shark whole, new model reveals</a>
</strong>
</em>
</p>
<hr>
<p>The book begins with an account of Tim as a teenage fossil-hunter in western Victoria. After unprecedented floods in 1973 expose a fresh layer of fossils for exploration, he finds a large megalodon tooth. From this moment, his passion is fired to find out more about this mysterious creature.</p>
<p>At the Museum of Victoria, Tim finds a curator who becomes his lifelong mentor. Tim had already found bits of a fossilised seal at Melbourne’s Beaumaris beach, so his mentor employs him to look for the rest of it on the understanding he must hand over anything he finds. On his first day’s dive, Tim discovers a beautiful, large, green megalodon tooth. He agonises over parting with it.</p>
<p>More than four decades later, he finds closure when he revisits this tooth at the museum. (Ironically, his mentor tells him: “I would have been happy for you to keep it.”) As he once more holds the tooth in his hand, reflecting on its rightful place in the museum’s collection, he realises he “had finally grown up”.</p>
<p>Throughout the book, Tim and Emma explore this tooth’s place in Earth’s emerging environments with an ease that comes with extensive knowledge of the subject. Drawing on comparative examples of fossilised prey, they imaginatively recreate the megalodon’s life in the ancient oceans as an apex predator. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/545440/original/file-20230830-30-9kn3uq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/545440/original/file-20230830-30-9kn3uq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/545440/original/file-20230830-30-9kn3uq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=409&fit=crop&dpr=1 600w, https://images.theconversation.com/files/545440/original/file-20230830-30-9kn3uq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=409&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/545440/original/file-20230830-30-9kn3uq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=409&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/545440/original/file-20230830-30-9kn3uq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=514&fit=crop&dpr=1 754w, https://images.theconversation.com/files/545440/original/file-20230830-30-9kn3uq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=514&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/545440/original/file-20230830-30-9kn3uq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=514&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Tim and Emma Flannery.</span>
<span class="attribution"><span class="source">Photo: Kate Holden</span></span>
</figcaption>
</figure>
<p>Exactly when the megalodon became extinct remains a mystery, but several reasons are offered as to why it did – including, perhaps, that the food required to sustain such enormous creatures was running low during the <a href="https://en.wikipedia.org/wiki/Pliocene">Pliocene</a> epoch (5.33 million to 2.58 million years ago). With fierce competition from sharks such as great whites, the supposedly bigger female megalodons, in particular, may have been just too large for the oceans to sustain the needs of any more than a small population. The species, write the authors, “may have always lived on a knife edge”.</p>
<p>As we follow this toothy tale, we learn of the cult of collectors, some of whom will go to extraordinary lengths, diving to dangerous, pitch-dark depths, to acquire a much-prized tooth. </p>
<p>Megalodon teeth vary considerably in appearance because of the absorption of particular chemicals in rocks and sediment in the many locations where they have been found. The authors describe the beauty of some of the teeth they have seen – jewel-like, variously coloured and patterned – pointing readers towards some of the likeliest sites for successful fossil-hunting. The US east coast (especially North Carolina) is a particularly rich hunting ground.</p>
<p>However, they point out that hunting is not without its dangers. Amateur fossil excavation can also risk disturbing valuable sites.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/meg-2-the-truth-about-the-extinct-mega-shark-and-why-even-this-ridiculous-film-could-inspire-future-palaeontologists-210751">Meg 2: the truth about the extinct mega shark – and why even this ridiculous film could inspire future palaeontologists</a>
</strong>
</em>
</p>
<hr>
<h2>Truth in a tooth</h2>
<p>In the absence of a fully fossilised megalodon discovery that might reveal its shape and likely weight, it seems there is still a lot of truth in a tooth. The largest megalodon tooth yet found is “18cm from base to tip” and “almost certainly came from an individual that exceeded 15m in length”.</p>
<p>The shape of the tooth and its serrations confirm its job was to kill other marine mammals. The tooth’s marks on ancient bones or positions within them can reveal what the megalodon ate, while its colour, pattern and lustre can reveal the location of the creature when it died. </p>
<p>The authors acknowledge that the megalodon is not the ancestor of the great white shark – but analogies are made with this shark to allow the reader to get some sense of the kind of creature the megalodon might have been.</p>
<p>Two chapters, “Shark Eats Man” and “Man Eats Shark”, are almost entirely taken up with accounts of great white sharks, tiger sharks or bull sharks, either attacking humans, being attacked, or otherwise being used by humans to feed their desire for shark deities, shark trophies or shark fin soup. All of this rather distracts from the otherwise entertaining and informative story.</p>
<p>There is real passion in this story, but also horror and terror. Given the frequent analogies made with much oppressed, present-day sharks, more moderate language might have been used. The poor <a href="https://en.wikipedia.org/wiki/Greenland_shark">Greenland sharks</a> are gruesomely described. The great whites and others become the stuff of nightmares. Readers who will never experience the beauty of these elegant and inquisitive creatures in their own environments may well associate these sharks with the imagined meg, a “terrifying”, “horrifying” “monster”, with “razor-sharp teeth” that is the star of this book.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/545150/original/file-20230829-20-qjp5ge.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/545150/original/file-20230829-20-qjp5ge.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/545150/original/file-20230829-20-qjp5ge.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=471&fit=crop&dpr=1 600w, https://images.theconversation.com/files/545150/original/file-20230829-20-qjp5ge.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=471&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/545150/original/file-20230829-20-qjp5ge.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=471&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/545150/original/file-20230829-20-qjp5ge.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=592&fit=crop&dpr=1 754w, https://images.theconversation.com/files/545150/original/file-20230829-20-qjp5ge.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=592&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/545150/original/file-20230829-20-qjp5ge.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=592&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Man Eating Shark. Two chapters of the book focus on human-shark interactions.</span>
<span class="attribution"><span class="source">Sculpture and Photo: Dave Williams</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/friday-essay-the-meg-is-a-horror-story-but-our-treatment-of-sharks-is-scarier-100886">Friday essay: The Meg is a horror story but our treatment of sharks is scarier</a>
</strong>
</em>
</p>
<hr>
<p>In a final chapter, the authors return to the megalodon. Cryptozoologists, who search the planet for signs that creatures believed to be extinct are still alive, are on the trail of the megalodon following <a href="https://www.australiangeographic.com.au/topics/wildlife/2017/08/everything-you-need-to-know-about-the-megamouth-shark/">the discovery by a US navy ship in 1976 of a supposedly extinct megamouth shark</a>, a contemporary of the megalodon.</p>
<p>Tim and Emma doubt megalodons are still out there. The sharks would hunt, they reason, where they would be seen by us and there have been no traces of even parts of a megalodon washed ashore, as in the case of other large and mysterious creatures.</p>
<p>However, they’re optimistic that further scientific discoveries will reveal more about the true shape and size of the creature. </p>
<p>If a complete set of teeth could be found – exactly as they lay in the mouth – this would reveal how the jaws worked, how many teeth there were, and what megalodons primarily hunted. If enough of a fossil was found to indicate the length and shape of the fins, we might learn more about the megalodon’s swimming and hunting strategies.</p>
<p>In 1988, the fossil of an extinct cartilaginous shark (<em>Carcharodon hubbelli</em>) was <a href="https://www.foxnews.com/science/whos-your-daddy-great-white-sharks-parent-found">unearthed by an olive farmer</a> in the <a href="https://en.wikipedia.org/wiki/Pisco_Formation">Pisco Formation of Southern Peru</a>.</p>
<p>Tim Flannery suggests that if a megalodon fossil were to be found, it would most likely be in the Pisco Formation “where the ancient sea floor, miraculously preserved, is laid out in exquisite detail”.</p>
<p>For now, the creature, whose arrowhead tooth once sat in his youthful hand – pointing him to the path of palaeontology – exists largely in his imagination: the “megalodon in all its terrifying glory”.</p><img src="https://counter.theconversation.com/content/211506/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vivienne Westbrook has been the recipient of many international research funding institutes, though is not presently being funded by any organisation.</span></em></p>Megalodons are having a cultural moment. What do we know about them? And might further scientific discoveries reveal more about the true shape and size of these creatures?Vivienne Westbrook, Adjunct Senior Research Fellow, Oceans Institute, The University of Western AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1235942019-09-16T20:39:41Z2019-09-16T20:39:41ZThe gloves are off: ‘predatory’ climate deniers are a threat to our children<figure><img src="https://images.theconversation.com/files/292532/original/file-20190916-19063-131y5d0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A child jumps from a rock outcrop into a lagoon in the low-lying Pacific island of Tuvalu.</span> <span class="attribution"><span class="source">AAP/Mick Tsikas</span></span></figcaption></figure><p>In this age of <a href="https://climate.nasa.gov/climate_resources/4/graphic-dramatic-glacier-melt/">rapidly melting glaciers</a>, <a href="https://www.nytimes.com/interactive/2019/07/31/magazine/paradise-camp-fire-california.html">terrifying megafires</a> and ever more puissant <a href="https://blogs.nasa.gov/hurricanes/tag/dorian-2019/">hurricanes</a>, of <a href="http://theconversation.com/acid-oceans-are-shrinking-plankton-fuelling-faster-climate-change-121443">acidifying</a> and <a href="https://theconversation.com/climigration-when-communities-must-move-because-of-climate-change-122529">rising</a> oceans, it is hard to believe that any further prod to climate action is needed.</p>
<p>But the reality is that we continue to live in a business-as-usual world. Our media is filled with enthusiastic announcements about <a href="https://www.smh.com.au/business/companies/cooper-energy-discovers-new-gas-field-20190906-p52onn.html">new fossil fuel projects</a>, or the unveiling of the latest <a href="https://www.drive.com.au/news/2019-frankfurt-motor-show-hits-and-misses-122435">fossil-fuelled supercar</a>, as if there’s no relationship between such things and climate change. </p>
<p>In Australia, the disconnect among our political leaders on the deadly nature of fossil fuels is particularly breathtaking.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/292545/original/file-20190916-19055-i8uqn6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/292545/original/file-20190916-19055-i8uqn6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/292545/original/file-20190916-19055-i8uqn6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/292545/original/file-20190916-19055-i8uqn6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/292545/original/file-20190916-19055-i8uqn6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/292545/original/file-20190916-19055-i8uqn6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/292545/original/file-20190916-19055-i8uqn6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Energy Minister Angus Taylor, left, and Prime Minister Scott Morrison. Both believe the polluting coal industry has a strong future in Australia.</span>
<span class="attribution"><span class="source">Lukas Coch/AAP</span></span>
</figcaption>
</figure>
<p>Prime Minister Scott Morrison continues to <a href="https://www.theguardian.com/australia-news/2017/feb/09/scott-morrison-brings-coal-to-question-time-what-fresh-idiocy-is-this">sing the praises of coal</a>, while members of the government call for subsidies for coal-fired power plants. A few days ago, Energy and Emissions Reduction Minister Angus Taylor urged that the nation’s old and polluting coal-fired power plants be allowed to <a href="https://minister.environment.gov.au/taylor/news/2019/2019-australian-energy-update">run “at full tilt”</a>. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/australia-to-attend-climate-summit-empty-handed-despite-un-pleas-to-come-with-a-plan-123187">Australia to attend climate summit empty-handed despite UN pleas to ‘come with a plan'</a>
</strong>
</em>
</p>
<hr>
<p>In the past, many of us have tolerated such pronouncements as the utterings of idiots – in the true, <a href="https://www.nytimes.com/2017/06/12/opinion/trump-and-the-true-meaning-of-idiot.html">original Greek meaning of the word</a> as one interested only in their own business. But the climate crisis has now <a href="https://www.ipcc.ch/sr15/">grown so severe</a> that the actions of the denialists have turned predatory: they are now an immediate threat to our children.</p>
<h2>A ‘colossal failure’ of climate activism</h2>
<p>Each year the situation becomes more critical. In 2018, global emissions of greenhouse gases <a href="https://www.iea.org/geco/">rose by 1.7%</a> while the concentration of carbon dioxide in the atmosphere <a href="https://research.noaa.gov/News/Scientist-Profile/ArtMID/536/ArticleID/2461/Carbon-dioxide-levels-hit-record-peak-in-May">jumped by 3.5 parts per million</a> – the largest ever observed increase.</p>
<p>No climate report or warning, no political agreement nor technological innovation has altered the ever-upward trajectory of the pollution. This simple fact forces me to look back on my <a href="https://www.abc.net.au/qanda/tim-flannery/10644160">20 years of climate activism</a> as a colossal failure.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/rivf479bW8Q?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Many climate scientists think we are already so far down the path of destruction that it is <a href="https://e360.yale.edu/features/negative-emissions-is-it-feasible-to-remove-co2-from-the-air">impossible to stabilise the global temperature at 1.5°C</a> above the pre-industrial average without yet to be developed <a href="https://www.anu.edu.au/events/welcome-to-the-2018-negative-emissions-conference-integrating-industry-technology-and-society">drawdown technologies</a> such as those that remove greenhouse gases from the atmosphere. On current trends, within a decade or so, stabilising at 2°C will likewise be beyond our grasp.</p>
<p>And on the other side of that threshold, nature’s <a href="https://climate.nasa.gov/nasa_science/science/">positive feedback loops</a> promise to fling us into a hostile world. By 2100 - just 80 years away – if our trajectory does not change, it is estimated that Earth will be <a href="https://climate.nasa.gov/news/2865/a-degree-of-concern-why-global-temperatures-matter/">4°C warmer</a> than it was before we began burning fossil fuels.</p>
<h2>Far fewer humans will survive on our warming planet</h2>
<p>That future Earth may have enough resources to support <a href="https://edition.cnn.com/2018/11/23/health/climate-change-report-bn/index.html">far fewer people</a> than the 7.6 billion it supports today. British scientist James Lovelock <a href="https://www.independent.co.uk/voices/commentators/james-lovelock-the-earth-is-about-to-catch-a-morbid-fever-that-may-last-as-long-as-100000-years-5336856.html">has predicted a future human population of just a billion people</a>. Mass deaths are predicted to result from, among other causes, <a href="https://theconversation.com/how-global-warming-is-adding-to-the-health-risks-of-poor-people-109520">disease outbreaks</a>, <a href="https://theconversation.com/climate-change-set-to-increase-air-pollution-deaths-by-hundreds-of-thousands-by-2100-81830">air pollution</a>, <a href="https://theconversation.com/climate-change-set-to-increase-air-pollution-deaths-by-hundreds-of-thousands-by-2100-81830">malnutrition and starvation</a>, <a href="https://www.brown.edu/news/2017-07-25/warming">heatwaves</a>, and <a href="https://theconversation.com/climate-change-will-increase-deaths-by-suicide-102156">suicide</a>. </p>
<p>My children, and those of many prominent polluters and climate denialists, will probably live to be part of that <a href="https://theconversation.com/climate-change-weve-created-a-civilisation-hell-bent-on-destroying-itself-im-terrified-writes-earth-scientist-113055">grim winnowing</a> – a world that the <a href="https://twitter.com/alanjones?lang=en">Alan Joneses</a> and <a href="http://www.heraldsun.com.au/blogs/andrew-bolt">Andrew Bolts</a> of the world have laboured so hard to create. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/292540/original/file-20190916-19030-1lcc3au.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/292540/original/file-20190916-19030-1lcc3au.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/292540/original/file-20190916-19030-1lcc3au.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/292540/original/file-20190916-19030-1lcc3au.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/292540/original/file-20190916-19030-1lcc3au.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/292540/original/file-20190916-19030-1lcc3au.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/292540/original/file-20190916-19030-1lcc3au.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Thousands of school students from across Sydney attend the global climate strike rally at Town Hall in Sydney in March 2019.</span>
<span class="attribution"><span class="source">Mick Tsikas/AAP</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/climigration-when-communities-must-move-because-of-climate-change-122529">'Climigration': when communities must move because of climate change</a>
</strong>
</em>
</p>
<hr>
<p>How should Australia’s parents deal with those who labour so joyously to create a world in which a large portion of humanity will perish? As I have become ever more furious at the polluters and denialists, I have come to understand they are threatening my children’s well-being as much as anyone who might seek to harm a child.</p>
<p>Young people themselves are now mobilising against the danger. Increasingly they’re giving up on words, and resorting to actions. <a href="https://rebellion.earth">Extinction Rebellion</a> is the Anthropocene’s answer to the UK working class <a href="https://www.nationalarchives.gov.uk/education/politics/g7/">Chartists</a>, the <a href="https://www.archives.gov/founding-docs/declaration-transcript">US Declaration of Independence</a>, and the defenders of the <a href="https://www.nma.gov.au/defining-moments/resources/eureka-stockade">Eureka Stockade</a>.</p>
<p>Its <a href="https://rebellion.earth/declaration/">declaration states</a>: </p>
<blockquote>
<p>This is our darkest hour. Humanity finds itself embroiled in an event unprecedented in its history, one which, unless immediately addressed, will catapult us further into the destruction of all we hold dear […] The wilful complicity displayed by our government has shattered meaningful democracy and cast aside the common interest in favour of short-term gain and private profit […] We hereby declare the bonds of the social contract to be null and void.</p>
</blockquote>
<h2>Words have not cut through. Is rebellion the only option?</h2>
<p>Not yet a year old, Extinction Rebellion has had an enormous impact. In April it <a href="https://www.theguardian.com/environment/2019/apr/22/people-arrested-at-london-climate-protests">shut down six critical locations in London</a>, overwhelmed the police and justice system with 1,000 arrests, and forced the British government to become the <a href="https://www.bbc.com/news/uk-politics-48126677">first nation ever</a> to declare a climate emergency.</p>
<p>So unstable is our current societal response that a single young woman, <a href="https://twitter.com/GretaThunberg?ref_src=twsrc%5Egoogle%7Ctwcamp%5Eserp%7Ctwgr%5Eauthor">Greta Thunberg</a>, has been able to spark a profoundly powerful global movement. Less than a year ago she went on a one-person school strike. Today school strikes for climate action are a <a href="https://www.schoolstrike4climate.com">global phenomenon</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/292547/original/file-20190916-19063-1s0diz7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/292547/original/file-20190916-19063-1s0diz7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/292547/original/file-20190916-19063-1s0diz7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/292547/original/file-20190916-19063-1s0diz7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/292547/original/file-20190916-19063-1s0diz7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/292547/original/file-20190916-19063-1s0diz7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/292547/original/file-20190916-19063-1s0diz7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Greta Thunberg, a 16-year-old climate change activist from Sweden, participates in a school strike in Washington in September 2019.</span>
<span class="attribution"><span class="source">Shawn Thew/EPA</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/climate-change-is-the-defining-issue-of-our-time-were-giving-it-the-attention-it-deserves-123592">Climate change is the defining issue of our time – we're giving it the attention it deserves</a>
</strong>
</em>
</p>
<hr>
<p>On September 20 in Australia and elsewhere, school principals must decide whether they will allow their students to <a href="https://www.schoolstrike4climate.com/sept20">march in the global climate strike</a> in an effort to save themselves from the climate predators in our midst, or force them to stay and study for a future that will not, on current trends, eventuate.</p>
<p>I will be marching with the strikers in Melbourne, and I believe teachers should join their pupils on that day. After all, us older generation should be painfully aware that our efforts have not been enough to protect our children.</p>
<p>The new and carefully planned rebellion by the young generation forces us earlier generations of climate activists to re-examine our strategy. Should we continue to use words to try to win the debate? Or should we become climate rebels? Changing the language around climate denialism will, I hope, sharpen our focus as we ponder what comes next.</p><img src="https://counter.theconversation.com/content/123594/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tim Flannery works for the Climate Council and the not-for-profit Ocean Forests Foundation. He receives funding from both organisations. He is affiliated with the Australian Museum and Melbourne University's Melbourne Sustainable Society Institute. </span></em></p>Climate deniers have joyously laboured to create a world potentially uninhabitable for our children. Our activism has failed, and rebellion may be the only answer.Tim Flannery, Professorial fellow, Melbourne Sustainable Society Institute, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/827482017-08-22T05:58:17Z2017-08-22T05:58:17ZSea the possibilities: to fight climate change, put seaweed in the mix<figure><img src="https://images.theconversation.com/files/182884/original/file-20170822-5153-1f5dnd6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Nadya Peek/Flickr</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>The next stage of humanity’s fight to reduce greenhouse emissions may revolve around seaweed, according to tonight’s episode of ABC’s Catalyst, presented by Professor Tim Flannery, which asks the question “can seaweed save the world?”</p>
<p>With the help of me and colleagues around the world, the documentary explores seaweed’s enormous potential to reduce greenhouse gases and draw CO₂ out of the atmosphere. In the case of seaweed, that could include <a href="https://theconversation.com/how-farming-giant-seaweed-can-feed-fish-and-fix-the-climate-81761">giant kelp farms that de-acidify oceans</a>, or feeding algae to cattle and sheep to <a href="http://www.abc.net.au/news/rural/2017-04-21/seaweed-fed-cows-could-solve-livestock-methane-problems/8460512">dramatically reduce their methane emissions</a>. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-farming-giant-seaweed-can-feed-fish-and-fix-the-climate-81761">How farming giant seaweed can feed fish and fix the climate</a>
</strong>
</em>
</p>
<hr>
<p>But while these possibilities are exciting, early adopters are dealing with unproven technology and complex international treaties. Globally, emissions are likely to keep rising, which means seaweed-related carbon capture should only be one part of a bigger emissions reduction picture. </p>
<h2>Net negative emissions</h2>
<p>To stay within the Paris climate agreement’s 2°C warming threshold, most experts agree that we must <a href="https://theconversation.com/we-need-to-get-rid-of-carbon-in-the-atmosphere-not-just-reduce-emissions-72573">remove carbon from the atmosphere</a> as well as reduce emissions. Many scientists now argue that 2°C will still cause dangerous climate change, and an upper limit of 1.5°C warming by 2100 is much safer. </p>
<p>To achieve that goal, humanity must begin reducing global emissions from 2020 (in less time than it takes an undergrad enrolling now to finish their degree) and rapidly decarbonise to zero net emissions by 2050.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-need-to-get-rid-of-carbon-in-the-atmosphere-not-just-reduce-emissions-72573">We need to get rid of carbon in the atmosphere, not just reduce emissions</a>
</strong>
</em>
</p>
<hr>
<p>Zero net carbon emissions can come from radical emissions reductions, and massive geoengineering projects. But it could be vastly helped by what Flannery calls “<a href="https://theconversation.com/theres-another-way-to-combat-climate-change-but-lets-not-call-it-geoengineering-46519">the third way</a>”: mimicking or strengthening Earth’s own methods of carbon capture. </p>
<p>Studies support the need to <a href="https://www.nature.com/articles/nclimate2572.epdf?shared_access_token=LD97ygQNSahFYailOr6vG9RgN0jAjWel9jnR3ZoTv0N5La99TIhV-eXtIfs2Rhl62avS_ey73Dz5PvwzgRV7mtfglTUuWeoMChMr24JsXcHDqYMpPeGzQIY7U76Mj3hJzErFkEqBsbUUn6FXlSPotV2inObntdBoHJHBkgXs8CU%3D">remove carbon from the atmosphere</a>, but there are serious <a href="http://science.sciencemag.org.ezp.lib.unimelb.edu.au/content/354/6309/182">technical, economic and political issues</a> with many <a href="http://rdcu.be/u9v8">large-scale plans</a>. </p>
<p>On the other hand, seaweed solutions could be put to work in the biologically desert-like “doldrums” of the ocean, and have positive side effects such as helping to clear up the <a href="https://theconversation.com/redrawing-the-map-could-reveal-ocean-garbage-patch-culprits-31163">giant ocean rubbish patches</a>. However, there are many technical problems still to be solved to make this a reality.</p>
<h2>We probably haven’t reached peak emissions</h2>
<p>Removing carbon from the atmosphere is an attractive proposition, but we can’t ignore the emissions we’re currently pumping out. For any negative emissions technology to work, our global emissions from fossil fuels must start to drop significantly, and very soon. </p>
<p>But wait a second, haven’t we <a href="http://fortune.com/2017/03/17/world-co2-emissions-stalled-last-year-thanks-to-the-u-s/">already hit peak emissions</a>? It’s true that for the <a href="https://theconversation.com/fossil-fuel-emissions-have-stalled-global-carbon-budget-2016-68568">third year in a row</a>, global carbon dioxide emissions from fossil fuels and industry have barely grown, while the global economy has continued to grow strongly.</p>
<p>This is great news, but the slowdown in emissions growth has been driven primarily by China, alongside the United States, and a general decline of emissions in developed countries. </p>
<p>China’s reductions are impressive. The country <a href="https://www.theguardian.com/environment/2016/jul/25/china-coal-peak-hailed-turning-point-climate-change-battle">peaked in coal</a> consumption in 2014, and tends to <a href="http://www.tandfonline.com/doi/abs/10.1080/14693062.2016.1156515">under-promise and over-deliver on emissions reductions</a>. However, under the Paris agreement, China has committed to a 60-65% reduction in emissions intensity, which means there’s <a href="https://www.nature.com/articles/nclimate2892">still room for them to rise in the future</a>.</p>
<p>India’s emissions, on the other hand, are major wild card. With a population of <a href="https://www.un.org/development/desa/en/news/population/world-population-prospects-2017.html">1.3 billion and rising</a>, about <a href="https://www.nature.com/articles/nclimate2892">300 million of whom are still not connected to an electrical grid</a>, and potential increases in <a href="https://theconversation.com/india-is-hedging-its-bets-on-coal-to-bring-power-to-the-people-54657">coal use to provide energy</a>, India will be vital to stabilising greenhouse gases. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/to-slow-climate-change-india-joins-the-renewable-energy-revolution-78321">To slow climate change, India joins the renewable energy revolution</a>
</strong>
</em>
</p>
<hr>
<p>India’s emissions today match those of China in 1990. A study that combined India’s Paris agreement targets with OECD estimates about its long-term economic growth, suggested <a href="http://palgrave.nature.com/nclimate/journal/v6/n1/full/nclimate2892.html">India’s CO₂ emissions could still grow significantly by 2030</a> (although per capita emissions would still be well below China and the US). </p>
<h2>The emissions reduction relay race</h2>
<p>So how do we deal with many competing and interconnected issues? Ideally, we need an array of solutions, with complementary waves of technology handling different problems. </p>
<p>Clearly the first wave, the clean energy transition, is well under way. Solar installations are <a href="https://www.greentechmedia.com/articles/read/iea-global-installed-pv-capacity-leaps-to-303-gw">breaking records</a>, with an extra 75 gigawatts added to our global capacity in 2016, up from 51 gigawatts installed in 2015. But this still represents just 1.8% of total global electricity demand.</p>
<p>In addition to renewable energy generation, limiting warming to below 1.5°C also means we must increase the efficiency of our existing grid. Fortunately, early-stage financiers and entrepreneurs are focusing on a <a href="http://www.nature.com/nclimate/journal/v7/n6/full/nclimate3306.html?WT.feed_name=subjects_technology">second wave of smart energy</a>, which includes efficiency and optimisation technologies. Others in Australia have also noted the opportunities offered by the increasing use of using <a href="http://www.2xep.org.au/files/2xEP_Innovation_Report_Phase_1_v2.pdf">small, smart devices connected to the internet that respond to user demand</a>. </p>
<p>Although <a href="https://theconversation.com/smart-home-gadgets-promise-to-cut-power-bills-but-many-lie-idle-or-can-even-boost-energy-use-82252">early user results have been mixed</a>, research shows better system control <a href="http://www.natureworldnews.com/articles/14801/20150521/climate-change-limiting-future-warming-to-1-5%C2%B0c-not-impossible.htm">reduces the emissions intensity of energy generation</a>. These energy efficient devices and optimisation software are on the cusp of becoming <a href="http://freelectrons.co/">widely commercially available</a>. </p>
<p>Critically, these efficiency technologies will be needed to complement structural change in the fossil fuel energy mix. This is especially in places where emissions are set to grow significantly, like India. Building renewable energy capacity, optimising with new software and technologies, and better understanding the opportunity for net negative emissions all play an important part in the emissions reductions relay race over the next 50 years to get us to 1.5°C.</p>
<p>With further research, development, and commercialisation, the possibilities offered by seaweed – outlined in more detail in the Catalyst documentary – are potentially game-changing. </p>
<p>But, as we saw with the development of renewable energy generation technology, it takes a long time to move from a good idea to wide implementation. We must support the scientists and entrepreneurs exploring zero-carbon innovations – and see if seaweed really can save the world. </p>
<p><br></p>
<hr>
<p><em><a href="https://tv.press.abc.net.au/catalyst-can-seaweed-save-the-world">Can Seaweed Save the World?</a> airs on the ABC on Tuesday 22 August at 8.30pm.</em></p><img src="https://counter.theconversation.com/content/82748/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adam Bumpus receives funding from the University of Melbourne Faculty of Science, the Australian Research Council (DECRA fellowship), and received financial compensation from the ABC for time working on the documentary. </span></em></p>Tonight on the ABC’s Catalyst, scientist Tim Flannery asks if seaweed can save the world. It’s a bold claim for algae, but seaweed could play a key role in keeping climate change in check.Adam Bumpus, Senior Lecturer, Environment & Innovation, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/730452017-02-20T04:14:50Z2017-02-20T04:14:50ZFactCheck Q&A: was it four degrees hotter 110,000 years ago?<figure><img src="https://images.theconversation.com/files/157278/original/image-20170217-4271-6avur5.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Senator Jacqui Lambie, speaking on Q&A.</span> <span class="attribution"><span class="source">Q&A</span></span></figcaption></figure><p><strong>The Conversation fact-checks claims made on Q&A, broadcast Mondays on the ABC at 9:35pm. Thank you to everyone who sent us quotes for checking via <a href="http://www.twitter.com/conversationEDU">Twitter</a> using hashtags #FactCheck and #QandA, on <a href="http://www.facebook.com/conversationEDU">Facebook</a> or by <a href="mailto:checkit@theconversation.edu.au">email</a>.</strong></p>
<hr>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/VunHZ7cCCyw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<blockquote>
<p>JACQUI LAMBIE: First of all, we’ve always had climate change – it’s been much, much hotter and much, much colder. Even 110,000 years ago, it was four degrees hotter. Charging our pensioners and our businesses and families more for power…</p>
<p>TONY JONES: There’ll be fact checkers on that one, Jacqui…– <strong>Tasmanian senator Jacqui Lambie, <a href="http://www.abc.net.au/tv/qanda/txt/s4612398.htm">speaking on Q&A</a> with host Tony Jones, February 13, 2017</strong></p>
</blockquote>
<p>With renewable energy, heatwaves and climate change back in the headlines, Tasmanian senator Jacqui Lambie told Q&A that it was four degrees hotter 110,000 years ago.</p>
<p>Is that right?</p>
<h2>Checking the source</h2>
<p>When asked for sources to support her statement, a spokesman for Jacqui Lambie referred The Conversation to Al Gore’s book <a href="https://www.amazon.com/Inconvenient-Truth-Planetary-Emergency-Warming/dp/B000QEJ0WY">An Inconvenient Truth</a> and Tim Flannery’s book <a href="http://www.theweathermakers.org/">The Weather Makers</a>.</p>
<p>The spokesman confirmed that Lambie was referring to 4°C, not Fahrenheit, and added:</p>
<blockquote>
<p>… most people think that the average world temperature has been constant for millions of years. The Gore and Flannery books prove it hasn’t.</p>
</blockquote>
<p>The detailed response from Lambie’s office, which is available <a href="http://theconversation.com/full-response-from-a-spokesperson-for-jacqui-lambie-for-a-factcheck-on-climate-change-73064">here</a>, included a chart from Gore’s book An Inconvenient Truth, which Lambie’s office had annotated. That chart is based on <a href="https://www.ncdc.noaa.gov/paleo-search/study/6080">data</a> from <a href="http://science.sciencemag.org/content/317/5839/793">Antarctic ice cores</a>. A response that The Conversation sourced from Tim Flannery on Lambie’s representation of his work can also be found <a href="http://theconversation.com/full-response-from-a-spokesperson-for-jacqui-lambie-for-a-factcheck-on-climate-change-73064">here</a>. </p>
<p>Let’s check the scientific evidence.</p>
<h2>Warmer, compared to what?</h2>
<p>Most non-scientists probably think in terms of “warmer than today” or “cooler than today”.</p>
<p>However, much of the science on this compares past and projected temperatures to a <a href="https://www.climate-lab-book.ac.uk/2017/defining-pre-industrial/">pre-industrial baseline</a>, not to the temperature today in 2017. That’s because temperatures now are rising too rapidly to serve as a useful baseline. (Industrialisation began in the late 18th century, and the world has warmed by <a href="https://climate.nasa.gov/evidence/">about 1°C since then</a>).</p>
<p>In this FactCheck, we will talk about both: comparing to pre-industrial levels and comparing to today.</p>
<h2>Was it ‘much, much hotter’ and ‘much, much colder’ in the past?</h2>
<p>Lambie was right to say that the Earth’s climate has always changed and that, at different times, Earth has been hotter and colder than today.</p>
<p>The past 650,000 years of Earth’s history (the interval shown in the annotated chart provided by Lambie’s office) was characterised by large climate swings as Earth moved naturally in and out of “ice ages” <a href="https://theconversation.com/ice-ages-have-been-linked-to-the-earths-wobbly-orbit-but-when-is-the-next-one-70069">triggered by changes in its orbit relative to the Sun</a>. </p>
<p>Initial cooling, brought on by slow changes to the shape of the Earth’s orbit and wobble of the Earth’s axis, was <a href="https://www.epa.gov/climate-change-science/causes-climate-change">amplified by natural effects</a>, including the growing ice sheets and the drawing down of carbon dioxide into the deep oceans. Over tens of thousands of years these <a href="https://www.theguardian.com/environment/2011/jan/05/climate-change-feedback-loops">amplifying feedbacks</a> caused Earth’s climate to descend into an ice age. </p>
<p>At the peak of the last ice age (around 20,000 years ago), Earth’s global average temperature is estimated by scientists to have been about <a href="http://www.nature.com/nature/journal/v538/n7624/full/nature19798.html">5-6°C cooler</a> than it was during the pre-industrial interval.</p>
<p>So, yes, it is fair to describe the ice ages as much, much colder than now. But were the warm periods of the last 650,000 years “much, much hotter”? </p>
<p>No. The warm climates of the so-called “interglacials” – meaning the period between ice ages – were similar to today. <a href="http://www.nature.com/nature/journal/v538/n7624/full/nature19798.html">A few of these periods</a> were a little bit hotter; some were a little bit cooler. </p>
<p>None had a <em>global</em> average temperature that was 4°C warmer than either today or pre-industrial times (we will return later to what the data say about <em>local</em> average temperatures).</p>
<h2>How warm was it 110,000 or so years ago?</h2>
<p>There was a warm interglacial period <a href="http://www.sciencedirect.com/science/article/pii/S0277379114003382">around 130,000 to 115,000 years ago</a>, before the last ice age. </p>
<p>This last interglacial period <em>was</em> one of the warmest periods of the past 650,000 years. But it wasn’t 4°C hotter globally. </p>
<p>Extensive <a href="http://rsta.royalsocietypublishing.org/content/371/2001/20130097">scientific evidence from across the globe</a> shows that the global average temperature during this interglacial period was <a href="http://www.nature.com/nature/journal/v538/n7624/full/nature19798.html">1-2°C warmer</a> than pre-industrial times (or about as warm as it was in 2016).</p>
<p>This evidence comes from <a href="https://www.ncdc.noaa.gov/news/what-are-proxy-data">natural climate archives</a>, including the tiny marine organisms that <a href="http://icestories.exploratorium.edu/dispatches/big-ideas/ice-and-sediment-cores/">accumulate as sediment on the bottom of the oceans</a> and whose chemical makeup fluctuates with surface ocean temperatures, and the <a href="https://theconversation.com/explainer-what-are-ice-cores-24302">water molecules in ice cores</a> that reflect air temperatures over the polar regions.</p>
<p>The last time Earth’s average temperature was 4°C warmer than pre-industrial levels was around <a href="http://rsta.royalsocietypublishing.org/content/371/2001/20120294">5-10 million years ago</a>. To put that in context, modern humans have existed for the last 200,000 years and civilised societies began to form only around 6,000 years ago.</p>
<h2>Global average temperatures versus local warming</h2>
<p>While the global average temperature during the last interglacial period was 1-2°C warmer than pre-industrial times, in some places like Antarctica and Greenland <em>local</em> warming resulted in temperatures as high as, <a href="http://www.nature.com/nature/journal/v493/n7433/full/nature11789.html">or even higher than</a>, 4°C warmer. These more extreme <em>local</em> temperature changes near the poles are referred to as
<a href="http://www.realclimate.org/index.php/archives/2006/01/polar-amplification/">polar amplification</a>.</p>
<p>Scientists have used ice-core data to calculate that during the last interglacial period Antarctica was around <a href="https://www.ncdc.noaa.gov/paleo/study/6080">3-5°C warmer</a> than it was during pre-industrial times. But <em>global</em> average temperatures were not 4°C warmer. </p>
<h2>Why does it matter?</h2>
<p>The fact that Earth has experienced natural climate changes in the past doesn’t downplay the significance of how humans are changing the climate now. </p>
<p>The vast amounts of coal, oil and gas burned since the Industrial Revolution in 1750 has caused the levels of <a href="https://www.co2.earth/">carbon dioxide in our atmosphere to rise</a> very significantly.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/UatUDnFmNTY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Time history of atmospheric carbon dioxide, by the Co-operative Institute for Research In Environmental Sciences (CIRES) and National Oceanic and Atmospheric Administration (NOAA)</span></figcaption>
</figure>
<p>Natural climate variations have continued to be a factor in Earth’s climate since the Industrial Revolution, but the rapid rise in carbon dioxide (and other greenhouse gases) has been the <a href="https://www.ipcc.ch/report/ar5/wg1/docs/WG1AR5_FAQbrochure_FINAL.pdf">dominant cause of climate warming during the industrial era</a>.</p>
<p>In 2016, the planet’s average surface temperature had risen to be about <a href="https://www.nasa.gov/press-release/nasa-noaa-data-show-2016-warmest-year-on-record-globally">1.1°C warmer than in the late 19th century</a>, when instrumental records began. This places our climate today at a similar global average temperature to the last interglacial.</p>
<hr>
<p><iframe id="tc-infographic-187" class="tc-infographic" height="2000" src="https://cdn.theconversation.com/infographics/187/6864d164de3795db8173059dc5a397f7e744e8fd/site/index.html" width="100%" style="border: none" frameborder="0"></iframe></p>
<hr>
<p>When global average temperatures were 1-2°C warmer than pre-industrial times between 115,000 and 130,000 years ago, this caused so much of the Antarctic and Greenland ice sheets to destabilise and melt that <a href="http://science.sciencemag.org/content/349/6244/aaa4019">sea level rose by 6-9 metres</a>.</p>
<p>It takes time to melt an ice sheet. But in some parts of Antarctica, climate warming since the Industrial Revolution has <a href="https://theconversation.com/we-can-now-only-watch-as-west-antarcticas-ice-sheets-collapse-26957">already triggered unstoppable changes in the ice sheets</a> that will likely commit us to the higher end of the <a href="https://theconversation.com/what-does-the-science-really-say-about-sea-level-rise-56807">28-98cm range of sea-level rise</a> predicted for the end of this century by the latest report from the Intergovernmental Panel on Climate Change.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/157267/original/image-20170217-4280-742ine.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/157267/original/image-20170217-4280-742ine.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/157267/original/image-20170217-4280-742ine.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=432&fit=crop&dpr=1 600w, https://images.theconversation.com/files/157267/original/image-20170217-4280-742ine.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=432&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/157267/original/image-20170217-4280-742ine.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=432&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/157267/original/image-20170217-4280-742ine.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=543&fit=crop&dpr=1 754w, https://images.theconversation.com/files/157267/original/image-20170217-4280-742ine.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=543&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/157267/original/image-20170217-4280-742ine.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=543&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Peak global mean temperature, atmospheric CO2, maximum global mean sea level (GMSL), and source(s) of meltwater. Light blue shading indicates uncertainty of GMSL maximum. Red pie charts over Greenland and Antarctica denote fraction (not location) of ice retreat.</span>
<span class="attribution"><a class="source" href="http://science.sciencemag.org/content/349/6244/aaa4019">Dutton et al. Sea-level rise due to polar ice-sheet mass loss during past warm periods, Science.</a></span>
</figcaption>
</figure>
<h2>Verdict</h2>
<p>Senator Jacqui Lambie’s description of past climate change on Q&A was not entirely correct. </p>
<p>She was right to say that Earth’s climate has always changed. It always will - driven by a wide range of natural causes, and now dominated by the growing influence of human activities such as burning fossil fuels. And at different times it has been hotter and colder than today.</p>
<p>But was it 4°C hotter 110,000 years ago, as Lambie said? No, not globally. </p>
<p>The Antarctic was about 4°C hotter during last interglacial period (around 130,000-115,000 years ago) than it was in pre-industrial times – but the <em>global</em> average temperature then was closer to 1-2°C warmer than pre-industrial times. </p>
<p>Our climate today is at a similar global average temperature to the last interglacial period about 130,000-115,000 years ago. <strong>– Nerilie Abram</strong></p>
<h2>Review</h2>
<p>This is a sound FactCheck. It is presented in a clear and accessible manner. In drawing its conclusions it cites a range of peer-reviewed scientific literature in our top journals. It highlights the key distinction between local and global temperature, and our understanding of polar amplification. </p>
<p>I would only add that the rate of warming over the last century is very unusual in the context of glacial and interglacial cycles. When the earth has moved out of ice ages in recent millennia it has taken, <a href="http://earthobservatory.nasa.gov/Features/GlobalWarming/page3.php">on average, 1,000 years</a> to warm the planet by 1°C. The earth’s temperature in recent decades has risen at around <a href="http://earthobservatory.nasa.gov/Features/GlobalWarming/page3.php">1°C per 100 years</a>, or <a href="http://theconversation.com/meet-el-ninos-cranky-uncle-that-could-send-global-warming-into-hyperdrive-72360">faster</a>. So the recent <em>rate</em> of warming is very unusual in this context. NASA makes this point <a href="http://earthobservatory.nasa.gov/Features/GlobalWarming/page3.php">here</a>. </p>
<p>The climate science community is very well aware of the record of past changes in the Earth’s climate. Indeed, these changes are part of the evidence for why we expect the rapid accumulation of greenhouse gases in the atmosphere due to human activity to produce large changes to the climate. <strong>– Ben Henley</strong></p>
<hr>
<p><div class="callout"> Have you ever seen a “fact” worth checking? The Conversation’s FactCheck asks academic experts to test claims and see how true they are. We then ask a second academic to review an anonymous copy of the article. You can request a check at checkit@theconversation.edu.au. Please include the statement you would like us to check, the date it was made, and a link if possible.</div></p><img src="https://counter.theconversation.com/content/73045/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nerilie Abram receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Ben Henley receives funding from an ARC Linkage Project and is an associate investigator with the ARC Centre of Excellence for Climate System Science.</span></em></p>During a Q&A discussion about climate change, Tasmanian Senator Jacqui Lambie said it was four degrees hotter 110,000 years ago. Is that right?Nerilie Abram, ARC Future Fellow, Research School of Earth Sciences; Chief Investigator for the ARC Centre of Excellence for Climate Extremes, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/465192015-08-25T04:19:10Z2015-08-25T04:19:10ZThere’s another way to combat climate change — but let’s not call it geoengineering<figure><img src="https://images.theconversation.com/files/92869/original/image-20150825-17760-f6jrsm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Geoengineering the climate may be more palatable if it supports natural processes.</span> <span class="attribution"><span class="source">Tree planting image from www.shutterstock.com</span></span></figcaption></figure><p>No matter how much we reduce greenhouse gas emissions, it will not be enough to keep global warming below 2C – the internationally agreed <a href="https://theconversation.com/a-matter-of-degrees-why-2c-warming-is-officially-unsafe-42308">“safe” limit</a>. This fact has been implied by the Intergovernmental Panel on Climate Change, and confirmed again recently by <a href="https://theconversation.com/reducing-emissions-alone-wont-stop-climate-change-new-research-45493">international research</a>. </p>
<p>Does this mean we should give up? Not at all. There is a plan B to keep warming below dangerous levels: helping the planet to take more carbon dioxide out of the atmosphere.</p>
<p>In his new book <a href="https://www.textpublishing.com.au/books/atmosphere-of-hope">Atmosphere of Hope</a>, Tim Flannery, Climate Councillor and Professorial Fellow at the Melbourne Sustainable Society Institute (and co-author of this article), argues that these strategies will be necessary to combat climate change, but cannot substitute completely for reducing emissions. </p>
<h2>Plan B</h2>
<p>When the term “plan B” is mentioned in relation to climate change, ideas immediately turn to the presumed “techno-fix” of geoengineering.</p>
<p><a href="https://theconversation.com/au/topics/geoengineering">Geoengineering</a>, or “climate engineering” as it is also known, is a broad, all-encompassing definition that includes both managing solar radiation and removing carbon dioxide from the atmosphere. </p>
<p>Solar radiation management techniques are those that change the balance of the sun’s energy reaching the earth, versus the amount being reflected out. Like deploying a parasol, this aims to cool the planet without adjusting greenhouse gas levels. </p>
<p>In contrast, carbon dioxide removal methods “suck” carbon dioxide from the atmosphere to store it semi-permanently either underground, in rocks, or in animals, plants and ecosystems.</p>
<p>Often the distinctions between these two methods (and their potential impacts and different governance challenges) are not made clear. It is not uncommon for the term “geoengineering” to be used only to refer to managing the sun’s radiation reaching the Earth. This is presumably why at the first international conference on climate engineering in 2014 the chair Mark Lawrence <a href="http://www.ce-conference.org/sites/default/files/wysiwyg/files/cec14_opening_statement_lawrence.pdf">called on all delegates</a> to be discerning and precise in their use of language.</p>
<p>Talk of geoengineering tends to elicit uncomfortable feelings. This is in part because it has no obvious governance – how do you decide who takes action that will affect the whole world? </p>
<p>It is also because many of the techniques under the geoengineering umbrella have <a href="http://climate.envsci.rutgers.edu/pdf/20Reasons.pdf">potentially serious adverse side-effects</a>, both environmental and social (like a cure that could be worse than the disease). It is also largely because it feels wrong, conceptually, to try to address a problem caused by the dominance of Man over Nature through the further dominance of Man over Nature. </p>
<h2>The third way</h2>
<p>If emissions reduction is not enough and geoengineering ideas <a href="http://decarboni.se/insights/what-and-what-isnt-geoengineering">are decried as</a> “ludicrous Bond-villain style schemes”, there must be another way … and there is.</p>
<p>According to <a href="http://link.springer.com/article/10.1007%2Fs10584-014-1148-6#page-1">research</a> from the Tyndall Centre for Climate Change Research, geoengineering methods that are perceived as “natural” are more likely to receive public support.</p>
<p>What this suggests is that humanity would be more accepting of new proposals to deal with climate change if they worked alongside natural processes. “Natural” options would be ones that strengthened and supported the environment in doing what it already does: processing excess atmospheric carbon dioxide. This is the third way to deal with climate change. </p>
<p>The analogy <a href="http://www.centerforcarbonremoval.org/blog/2015/7/28/open-letter-to-tim-flannery-in-response-to-a-third-way-to-fight-climate-change">has been drawn</a> to a person battling weight gain. Reducing calorie intake is important but this should be supplemented by exercise to help the body do what it already does: burn excess fat. This analogy also likens some geoengineering techniques to lap-band surgery.</p>
<p>The third way is thus a concept that is described in Atmosphere of Hope as:</p>
<blockquote>
<p>encompassing proposals and experiments that shed light on how Earth’s natural system for maintaining the carbon balance might be stimulated to draw CO<sub>2</sub> out of the air and sea at a faster rate than occurs presently, and how we might store the recovered CO<sub>2</sub> safely. </p>
</blockquote>
<p>In essence, the division between the third way and geoengineering is a functional one.</p>
<p>Third-way ideas are extremely varied. They include planting trees or building artificial trees that capture CO<sub>2</sub> from the air; producing and using <a href="https://theconversation.com/can-biochar-save-the-planet-1099">biochar</a>; farming CO<sub>2</sub>-absorbing seaweed; and constructing buildings from carbon-neutral cement capable of capturing CO<sub>2</sub> from the air. </p>
<p>Determining whether a particular idea aligns with the third-way concept needs to be done on a case-by-case basis. </p>
<p>Ocean fertilisation is a good example. It involves adding elements or compounds (such as iron, nitrogen, phosphate, silica, or urea) to the oceans in an area that is nutrient deficient. This stimulates biological growth that can absorb carbon through photosynthesis. </p>
<p>Although the concept builds on existing natural processes, the outcome is uncertain and research suggests that there are environmental risks such as damaging fisheries and marine biodiversity (see <a href="http://www.vliz.be/imisdocs/publications/141458.pdf">here</a>, <a href="http://www.whoi.edu/fileserver.do?id=45403&pt=2&p=28251">here</a> and <a href="http://www.vliz.be/imisdocs/publications/141440.pdf">here</a>), causing <a href="http://www.its.caltech.edu/%7Ebi1/Bi1__Micro-_to_Macro-Biology/Additional_Readings_files/Side%20Effects%20of%20Oceanic%20Iron%20Fertilization.pdf">localised warming</a>, <a href="http://www.sciencedirect.com/science/article/pii/S0967064506001986">altering cloud formations</a> and maybe even <a href="http://www.int-res.com/articles/theme/m364p283.pdf">increasing greenhouse gas emissions</a>. </p>
<p>Given the current state of research, ocean fertilisation does not look feasible or appropriate and thus may not qualify as third-way (despite sitting squarely under the geoengineering umbrella).</p>
<h2>Direct Action could do the job</h2>
<p>The third way may be easier for us to grapple with that geoengineering. This is perhaps because the third-way concept is already partially embedded in the Australian government’s approach to climate policy.</p>
<p>The government’s Direct Action mechanism is aimed at providing incentives for tackling rising atmospheric greenhouse gases. The Minister for the Environment <a href="http://www.int-res.com/articles/theme/m364p283.pdf">has called</a> Direct Action “source blind as to the type of abatement”. That means that the policy instrument does not discriminate on the technology or the sector within which the abatement takes place. </p>
<p>Direct Action also does not discriminate between emissions reduction and emissions removal (despite being financed by a government purse known as the Emissions Reduction Fund). In fact, the long title of the <a href="https://www.comlaw.gov.au/Details/C2015C00260">legislation</a> is “An Act about projects to remove carbon dioxide from the atmosphere and projects to avoid emissions of greenhouse gases, and for other purposes”. </p>
<p>Of the 30 or so <a href="http://www.environment.gov.au/climate-change/emissions-reduction-fund/methods">methods</a> currently available for funding under the Emissions Reduction Fund only a small handful could be classified as third-way. And at this stage they are all within the agriculture and forestry sector. </p>
<p>This is because the legislation for Direct Action is inherited from the previous government’s Carbon Farming Initiative that focused exclusively on the land sector. However, technically (if not economically) there is the potential for third-way methods to gain more importance under Direct Action.</p>
<h2>The third-way cannot be the only way</h2>
<p>What should not be ignored, however, is the fact that the total capacity for third-way methods to help meet the climate change challenge is limited by a number of factors, including by nature itself, but also the pace of innovation and funding.</p>
<p>In Atmosphere of Hope, it is estimated that by mid-century up to about 40% of current global emissions could potentially be absorbed in this way. </p>
<p>Globally emissions from the burning fossil fuels and from cement production continue to increase. </p>
<p>In Australia, emissions from the combustion of fossil fuels levelled off in 2009, and even started to decrease (from reduced electricity demand) but have started to increase again in the latest financial year. The third way can only be a supplement to serious emissions reduction in Australia and worldwide, it should not be seen as a substitute. </p>
<p><em>The launch of Tim Flannery’s latest book, <a href="https://www.textpublishing.com.au/books/atmosphere-of-hope">Atmosphere of Hope: Searching for Solutions to the Climate Crisis</a>, will be hosted by the Melbourne Sustainable Society Institute on Wednesday 26 August. Tickets are available <a href="http://sustainable.unimelb.edu.au/atmosphere-hope-tim-flannery">here</a>.</em></p><img src="https://counter.theconversation.com/content/46519/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Anita Talberg is on an Australian Postgraduate Award PhD scholarship.</span></em></p><p class="fine-print"><em><span>Tim Flannery is author of Atmosphere of Hope. He is a Climate Councillor for the Climate Council and a pro-bono judge on Richard Branson's £25 million Virgin Earth Challenge.</span></em></p>No matter how much we reduce greenhouse gas emissions, it will not be enough to keep global warming below 2C. Does this mean we should give up? Not at all.Dr Anita Talberg, PhD student in the Australian German Climate and Energy College, The University of MelbourneTim Flannery, Professorial fellow, Melbourne Sustainable Society Institute, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/100892012-12-20T03:33:55Z2012-12-20T03:33:55ZScientists and national park managers are failing northern Australia’s vanishing mammals<figure><img src="https://images.theconversation.com/files/18736/original/vf88ysyp-1355705581.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An early dry season fire in Kakadu National Park – are these fires burning up our mammals?</span> <span class="attribution"><span class="source">Clay Trauernicht</span></span></figcaption></figure><p>Conservationists should take heart that Australia is finally waking up to the biodiversity crisis in Australia’s north. It is an urgent problem: right now, a diverse assortment of our small mammals – bandicoots, tree-rats, possums - are rapidly vanishing from northern Australia’s most iconic biodiversity strongholds.</p>
<p><a href="http://www.publish.csiro.au/paper/WR09125">Work in Kakadu National Park</a> has shown that between 1996 and 2009 mammal populations crashed, with species richness and total abundance decreasing by 65% and 75% respectively.</p>
<p>Most alarming is that scientists can’t tell us why this is happening, let alone how to stop it.</p>
<p>Prominent conservationist Tim Flannery recently drew attention to the plight of northern Australian mammals in his <a href="http://www.quarterlyessay.com/issue/after-future-australias-new-extinction-crisis">Quarterly Essay</a> and accompanying article in <a href="http://theconversation.com/the-future-for-biodiversity-conservation-isnt-more-national-parks-11027">The Conversation</a> (as have others writing in <a href="http://theconversation.com/the-kimberley-pristine-precious-and-on-the-precipice-1266">The Conversation</a> and <a href="http://www.theaustralian.com.au/news/health-science/extinction-risk-in-kakadu-national-park/story-e6frg8y6-1226410521540">other media</a>). Though valuable, these articles tend to oversimplify the complex and unresolved ecological questions that must underpin an appropriate management response.</p>
<p>Flannery asserts that <a href="http://theconversation.com/the-future-for-biodiversity-conservation-isnt-more-national-parks-11027">“the main driver appears to be changes in fire regime, compounded by the presence of feral cats”</a>. This overstates our current understanding.</p>
<p>Unlike most other conservation issues in Australia, the most immediate obstacle is lack of knowledge. We simply don’t know why mammals are declining or what management interventions could halt the decline.</p>
<h2>Frequent fire hazards</h2>
<p>There is widespread agreement that the mammal decline has <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1755-263X.2011.00164.x/abstract"><em>something</em> to do with fire</a>. However, scientists have failed to answer the critical question – with a large budget, what type of fire regime should (and could) land managers implement to benefit small mammals?</p>
<p>The managers of Kakadu - the epicentre of the northern mammal decline - have been <a href="http://conservationbytes.com/2009/08/21/shocking-continued-loss-of-australian-mammals/">roundly criticised</a> by conservation scientists for their excessive use of prescribed burning to prevent high-intensity wildfires. However, these same scientists have been remarkably silent on alternative management approaches.</p>
<p>There is evidence that high fire frequencies are detrimental to small mammals, demonstrated most significantly in the work by <a href="http://www.publish.csiro.au/paper/WR09125">John Woinarski and colleagues</a>. They found that in Kakadu, sites that had been most frequently burnt experienced the greatest small mammal declines over the period 1996-2009.</p>
<p>The challenge is understanding exactly what it is about fire regimes that has changed. The breakdown of <a href="https://theconversation.com/the-biggest-estate-on-earth-how-aborigines-made-australia-3787">traditional Aboriginal fire management</a> - and possible increase in the size and intensity of fires - is often <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1755-263X.2011.00164.x/abstract">suggested as a trigger</a>. However, in places like Kakadu this occurred many decades before mammal populations crashed.</p>
<h2>A tinderbox landscape</h2>
<p>There is a widely held view that there is too much fire in parks like Kakadu. However, calls for widespread reductions in fire frequency in the north tend to overlook the <a href="https://theconversation.com/the-worst-fire-season-ever-until-next-year-3452">fundamental ecology of fire</a>.</p>
<p>Fire is so prevalent in this region not because of people, but because of the intense monsoon climate. A reliable wet season promotes rapid grass growth, and a long dry season promotes drying of grassy fuels. </p>
<p>Abundant lightning at the end of the dry season ensures high fire activity. The effect of humans is to merely “jump start” the fire season, providing an ignition source earlier in the year.</p>
<p>It is inevitable that a large proportion of the landscape burns each year. For Kakadu, this figure is remarkably constant at <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1442-9993.2000.tb00067.x/abstract">around 45%</a>.</p>
<p>The only <a href="http://www.publish.csiro.au/?paper=WF10079">“lever” available to land managers</a> is whether burning occurs predominantly in the early (April–July) or late (August–November) dry season.</p>
<p>This fact has driven the prevailing approach to fire management in northern Australia – that of extensive early dry season burning to pre-empt intense late dry season fires.</p>
<h2>Fighting fire with fire</h2>
<p>Because they occur under milder fire conditions, early dry season fires tend to be significantly <a href="http://www.publish.csiro.au/?paper=WF05111">less intense</a>, <a href="http://www.publish.csiro.au/?paper=WF07150">smaller</a>, and <a href="http://www.publish.csiro.au/paper/WR03043">patchier</a> than late dry season fires.</p>
<p>It is well known that many fire-sensitive plants (such as the <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2745.2012.01970.x/abstract">northern cypress pine</a>, and to a lesser extent sandstone heaths) benefit from an earlier fire regime. There is also <a href="http://www.sciencedirect.com/science/article/pii/S0006320710000686">evidence</a> that this applies to small mammals too.</p>
<p>Based on satellite-derived fire mapping since 1980, we know that the proportion of Kakadu that burns each year has not changed over the last 32 years. However, it is clear that there has been a dramatic switch from late dry season to early dry season fires. Although such a shift in fire season is thought to be good for biodiversity, including mammals, there may be more insidious changes that have taken place.</p>
<p>For example, retired Kakadu ranger <a href="http://blogs.abc.net.au/nt/2012/07/kakadu-on-the-verge-of-extinction.html?site=darwin&program=darwin_drive">Greg Miles</a> has suggested that a vicious grass–fire cycle is now firmly established in Kakadu. The theory is that highly flammable speargrass (<em>Sorghum</em> species) increased in abundance following the breakdown of Aboriginal fire management, and now fuels fires of much greater intensity. </p>
<p>Even in the early dry season, speargrass fires tend to be of high intensity and <a href="http://search.informit.com.au/documentSummary;dn=520624831539387;res=IELHSS">low patchiness</a>. Hence, abundant speargrass effectively negates the advantages of early dry season prescribed burning.</p>
<p>It is noteworthy that the introduced swamp buffalo was virtually eradicated from Kakadu in the 1980s, after more than a century in the park. <a href="http://www.esajournals.org/doi/abs/10.1890/06-1599.1?journalCode=emon">Some suggest</a> that this may have further promoted an increase in speargrass abundance and fire intensity. The only major change to have immediately preceded the mammal collapse in Kakadu was the eradication of the buffalo.</p>
<p>Whether a grass-fire cycle can be reversed is not clear. One option put forward is to <a href="http://www.savanna.org.au/view/34903/fire-and-spear-grass-a-case-for-wet-season-burning-in-kakadu.html">burn heavily infested areas in the wet season</a>, before the speargrass can produce seed. Another option that warrants objective consideration is <a href="http://theconversation.com/elephants-on-grass-only-lively-debate-can-save-australias-environment-5287">grazing by exotic herbivores</a>, especially as highly-flammable exotic grasses overtake the park.</p>
<p>We need a better understanding of how fire regimes have changed over the last century. Despite Kakadu having the best-described fire regimes in northern Australia, the available fire records are still relatively short (from 1980 on). These satellite-derived records are also limited to fire frequency, size and season. Recent changes in a broader spectrum of fire regime attributes, such as intensity and fine-scale patchiness, are highly uncertain.</p>
<h2>Testing the critics’ claims</h2>
<p>Vague calls for “less fire” are unhelpful. Instead, we need to specifically identify what kinds of fire management work best for mammals at landscape scales. This means considering the intervals between fires, fire intensity, size and patchiness.</p>
<p>We also need to determine whether areas of long, unburnt vegetation are important for small mammals’ survival, and how different species are affected by “mosaic” burning practices, in which fires of varying intensities, scales and times are burnt to create a patchwork or mosaic effect in the landscape. </p>
<p>Some <a href="http://www.pnas.org/content/105/39/14796.short">researchers</a> suggest that Aboriginal fire management would have resulted in such a mosaic, and the loss of this mosaic has triggered biodiversity declines. Although intuitively appealing, there is remarkably little direct evidence to support this hypothesis, especially in relation to small mammals.</p>
<p>The greatest challenge will be to translate these research findings into explicit management actions.</p>
<p>For example, <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1442-9993.2011.02334.x/full">Alan Andersen and colleagues</a> described an approach to increasing the abundance of long unburnt areas, without actually decreasing the proportion of the landscape burnt each year. The trick is to decrease the randomness of burning, by concentrating prescribed burning on recently burnt areas, avoiding long unburnt areas.</p>
<p>If the current model of extensive early dry season burning is so obviously failing, then there is an onus on its critics to propose something new.</p>
<h2>Unlocking answers from the land</h2>
<p>Land managers need to do their bit too by facilitating collaborative research in conservation areas.</p>
<p>Sadly, national parks can be difficult places to conduct research in northern Australia, hindered by slow-moving bureaucracies and priorities other than biodiversity conservation.</p>
<p>The quantity and quality of research coming out of <a href="http://www.australianwildlife.org/">Australian Wildlife Conservancy</a> properties in the Kimberley demonstrates how much easier it can be to conduct conservation research on private land.</p>
<p>Close collaboration between scientists and land managers is essential, ideally within an <a href="http://en.wikipedia.org/wiki/Adaptive_management">adaptive management</a> framework. This is where new management interventions can be repeatedly tried, evaluated, improved or potentially abandoned.</p>
<p>Most importantly, unorthodox management interventions need to be objectively evaluated. These might range from grazing by large exotic herbivores (such as buffalo and cattle) to reduce fuel loads, to wet season burning of annual grasses.</p>
<p>As Tim Flannery points out, <a href="http://theconversation.com/the-future-for-biodiversity-conservation-isnt-more-national-parks-11027">“things are now so dire that we cannot afford to persist with business as usual”</a>.</p><img src="https://counter.theconversation.com/content/10089/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brett Murphy receives funding from the Australian Research Council and the National Environmental Research Program.</span></em></p><p class="fine-print"><em><span>Clay Trauernicht receives funding from ARC.</span></em></p><p class="fine-print"><em><span>David Bowman receives funding from the ARC, NASA, TERN and NERP. He serves on the Kakadu National Park Research Advisory Committee.</span></em></p>Conservationists should take heart that Australia is finally waking up to the biodiversity crisis in Australia’s north. It is an urgent problem: right now, a diverse assortment of our small mammals – bandicoots…Brett Murphy, Research Fellow, The University of MelbourneClay Trauernicht, Student, University of TasmaniaDavid Bowman, Professor, Environmental Change Biology, University of TasmaniaLicensed as Creative Commons – attribution, no derivatives.