<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div style="margin: 0px; font-stretch: normal; line-height: normal; background-color: rgb(255, 255, 255);" class=""><div style="font-variant-ligatures: normal; orphans: 2; widows: 2; margin: 0px; font-stretch: normal; line-height: normal;" class=""><cite style="box-sizing: inherit; font-variant-ligatures: normal;" class="">Science Advances </cite><span style="font-variant-ligatures: normal;" class=""> 05 Jul <b class="">2017</b></span></div></div><div style="margin: 0px; font-stretch: normal; line-height: normal; color: rgb(17, 85, 204); background-color: rgb(255, 255, 255);" class=""><span style="text-decoration: underline; -webkit-font-kerning: none;" class=""><a href="http://advances.sciencemag.org/content/3/7/e1602821" class="">http://advances.sciencemag.org/content/3/7/e1602821</a></span></div><div style="margin: 0px; font-stretch: normal; line-height: normal; color: rgb(34, 34, 34); background-color: rgb(255, 255, 255); min-height: 12px;" class=""><span style="font-kerning: none" class=""></span><br class=""></div><div style="margin: 0px; font-stretch: normal; line-height: normal; color: rgb(34, 34, 34); background-color: rgb(255, 255, 255);" class=""><span style="font-kerning: none" class=""><b class="">Excerpts from plain language reporting in The Guardian </b></span></div><div style="margin: 0px; font-stretch: normal; line-height: normal; color: rgb(34, 34, 34); background-color: rgb(255, 255, 255); min-height: 12px;" class=""><span style="font-kerning: none" class=""></span><br class=""></div><div style="margin: 0px; font-stretch: normal; line-height: normal; color: rgb(51, 51, 51); background-color: rgb(255, 255, 255);" class=""><span style="font-kerning: none" class="">Computer models have long indicated a high level of sensitivity, up to 4.5C for a doubling of CO2 in the atmosphere.</span></div><div style="margin: 0px; font-stretch: normal; line-height: normal; color: rgb(51, 51, 51); background-color: rgb(255, 255, 255); min-height: 17px;" class=""><span style="font-kerning: none" class=""></span><br class=""></div><div style="margin: 0px; font-stretch: normal; line-height: normal; color: rgb(51, 51, 51); background-color: rgb(255, 255, 255);" class=""><span style="font-kerning: none" class="">However in recent years estimates of climate sensitivity based on historical temperature records from the past century or so have suggested the response might be no more than 3C. </span></div><div style="margin: 0px; font-stretch: normal; line-height: normal; color: rgb(51, 51, 51); background-color: rgb(255, 255, 255); min-height: 17px;" class=""><span style="font-kerning: none" class=""></span><br class=""></div><div style="margin: 0px; font-stretch: normal; line-height: normal; color: rgb(51, 51, 51);" class=""><span style="-webkit-font-kerning: none;" class=""><span style="background-color: rgb(255, 255, 255);" class="">But the new work, using both models and paleoclimate data from warming periods in the Earth’s past, shows that the historical temperature measurements </span><span style="background-color: rgb(255, 251, 0);" class="">do not reveal</span><span style="background-color: rgb(255, 255, 255);" class=""> the slow heating of the planet’s oceans that takes place for decades or centuries after CO2 has been added to the atmosphere.</span></span></div><div style="margin: 0px; font-stretch: normal; line-height: normal; color: rgb(51, 51, 51); background-color: rgb(255, 255, 255); min-height: 17px;" class=""><span style="font-kerning: none" class=""></span><br class=""></div><div style="margin: 0px; font-stretch: normal; line-height: normal; color: rgb(51, 51, 51); background-color: rgb(255, 255, 255);" class=""><span style="font-kerning: none" class="">“The hope was that climate sensitivity was lower and the Earth is not going to warm as much,” said Cristian Proistosescu, at Harvard University in the US, who led the new research. </span></div><div style="margin: 0px; font-stretch: normal; line-height: normal; color: rgb(51, 51, 51); background-color: rgb(255, 255, 255); min-height: 17px;" class=""><span style="font-kerning: none" class=""></span><br class=""></div><div style="margin: 0px; font-stretch: normal; line-height: normal; color: rgb(51, 51, 51); background-color: rgb(255, 255, 255);" class=""><span style="font-kerning: none" class="">“There was this wave of optimism.”</span></div><div style="margin: 0px; font-stretch: normal; line-height: normal; color: rgb(51, 51, 51); background-color: rgb(255, 255, 255); min-height: 17px;" class=""><span style="font-kerning: none" class=""></span><br class=""></div><div style="margin: 0px; font-stretch: normal; line-height: normal;" class=""><span style="-webkit-font-kerning: none;" class=""><span style="background-color: rgb(255, 255, 255);" class="">The new research, </span><a href="http://advances.sciencemag.org/content/3/7/e1602821" style="background-color: rgb(255, 255, 255);" class=""><span style="font-stretch: normal; line-height: normal; -webkit-font-kerning: none; color: rgb(0, 0, 0);" class="">published in the journal Science Advances</span></a><span style="background-color: rgb(255, 255, 255);" class="">, has ended that. “The worrisome part is that all the models show there is an amplification of the amount of warming in the future,” he said. The situation might be even worse, as Proistosescu’s work shows climate sensitivity </span><span style="background-color: rgb(255, 251, 0);" class="">could be</span><span style="background-color: rgb(255, 255, 255);" class=""> as high as 6C.</span></span></div><div style="margin: 0px; font-stretch: normal; line-height: normal; color: rgb(148, 146, 0); background-color: rgb(255, 255, 255); min-height: 17px;" class=""><span style="font-kerning: none" class=""></span><br class=""></div><div style="margin: 0px; font-stretch: normal; line-height: normal; color: rgb(51, 51, 51); background-color: rgb(255, 255, 255);" class=""><span style="font-kerning: none" class="">Prof Bill Collins, at the University of Reading, UK, and not part of the new research, said: “Some have suggested that we might be lucky and avoid dangerous climate change without taking determined action if the climate is not very sensitive to CO2 emissions. This work provides new evidence that that chance is remote.” </span></div><div class="">
<div dir="auto" style="color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); font-variant-caps: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><br class=""><span style="font-weight: normal; font-style: normal; font-family: Verdana; background-color: rgb(255, 255, 255);" class="">**********************************<br class=""></span><div style="color: rgb(34, 34, 34); font-variant-ligatures: normal; orphans: 2; widows: 2; margin: 0px; font-stretch: normal; line-height: normal;" class=""><span style="background-color: rgb(255, 255, 255);" class=""><i style="font-weight: normal;" class="">Science April</i> 16, <b class="">2019</b></span></div><div style="font-weight: normal; color: rgb(34, 34, 34); font-variant-ligatures: normal; orphans: 2; widows: 2; margin: 0px; font-stretch: normal; line-height: normal;" class=""><div style="font-family: Arial, Helvetica, sans-serif; font-variant-ligatures: normal; margin: 0px; font-stretch: normal; line-height: normal; color: rgb(0, 0, 238);" class=""><span style="text-decoration: underline; -webkit-font-kerning: none; background-color: rgb(255, 255, 255);" class=""><a href="https://www.sciencemag.org/news/2019/04/new-climate-models-predict-warming-surge" target="_blank" data-saferedirecturl="https://www.google.com/url?q=https://www.sciencemag.org/news/2019/04/new-climate-models-predict-warming-surge&source=gmail&ust=1569624414033000&usg=AFQjCNG2SQeW3aBZbvqR8ymkn4i3MnJmKw" style="color: rgb(17, 85, 204);" class="">https://www.sciencemag.org/<wbr class="">news/2019/04/new-climate-<wbr class="">models-predict-warming-surge</a></span></div></div><div style="font-weight: normal; font-style: normal; font-family: Arial, Helvetica, sans-serif; color: rgb(34, 34, 34); font-variant-ligatures: normal; orphans: 2; widows: 2; margin: 0px; font-stretch: normal; line-height: normal; min-height: 14px;" class=""><span style="background-color: rgb(255, 255, 255);" class=""><br class=""></span></div><p style="font-weight: normal; font-style: normal; font-family: Arial, Helvetica, sans-serif; font-variant-ligatures: normal; orphans: 2; widows: 2; margin: 0px 0px 15px; font-stretch: normal; line-height: normal; color: rgb(51, 51, 51);" class=""><span style="-webkit-font-kerning: none; background-color: rgb(255, 255, 255);" class=""><b class="">New climate models predict a warming surge</b></span></p><div style="font-weight: normal; font-style: normal; font-family: Arial, Helvetica, sans-serif; font-variant-ligatures: normal; orphans: 2; widows: 2; margin: 0px; font-stretch: normal; line-height: normal; color: rgb(55, 88, 138);" class=""><span style="color: rgb(102, 102, 102); background-color: rgb(255, 255, 255);" class=""><b class="">By </b><a href="https://www.sciencemag.org/author/paul-voosen" target="_blank" data-saferedirecturl="https://www.google.com/url?q=https://www.sciencemag.org/author/paul-voosen&source=gmail&ust=1569624414033000&usg=AFQjCNEWkTq7TafXl7SJWoDT9h6GurVeaQ" style="color: rgb(17, 85, 204);" class=""><span style="color: rgb(55, 88, 138);" class=""><b class="">Paul Voosen</b></span></a></span></div><div style="font-weight: normal; font-style: normal; font-family: Arial, Helvetica, sans-serif; font-variant-ligatures: normal; orphans: 2; widows: 2; margin: 0px; font-stretch: normal; line-height: normal; color: rgb(55, 88, 138); min-height: 12px;" class=""><span style="background-color: rgb(255, 255, 255);" class=""><span style="font-kerning: none;" class=""><b class=""></b></span><br class=""></span></div><div style="font-weight: normal; font-style: normal; font-family: Arial, Helvetica, sans-serif; font-variant-ligatures: normal; orphans: 2; widows: 2; margin: 0px; font-stretch: normal; line-height: normal; color: rgb(0, 0, 238);" class=""><br class=""></div><p style="font-weight: normal; font-style: normal; font-family: Arial, Helvetica, sans-serif; font-variant-ligatures: normal; orphans: 2; widows: 2; margin: 0px 0px 15px; font-stretch: normal; line-height: normal; color: rgb(51, 51, 51);" class=""><span style="background-color: rgb(255, 255, 255);" class=""><span style="font-kerning: none;" class="">For nearly 40 years, the massive computer models used to simulate global climate have delivered a fairly consistent picture of how fast human carbon emissions might warm the world. But a host of global climate models developed for the United Nations’s next major assessment of global warming, <a href="https://wg1.ipcc.ch/AR6/AR6.html" target="_blank" data-saferedirecturl="https://www.google.com/url?q=https://wg1.ipcc.ch/AR6/AR6.html&source=gmail&ust=1569624414033000&usg=AFQjCNH79c9KIxr-FTfAGf-1XAIDpC4yYw" style="color: rgb(17, 85, 204);" class=""><span style="font-stretch: normal; line-height: normal;" class=""><b class="">due in 2021</b></span></a>, are now showing a puzzling but undeniable trend. They are <a href="https://www.carbonbrief.org/guest-post-why-results-from-the-next-generation-of-climate-models-matter" target="_blank" data-saferedirecturl="https://www.google.com/url?q=https://www.carbonbrief.org/guest-post-why-results-from-the-next-generation-of-climate-models-matter&source=gmail&ust=1569624414033000&usg=AFQjCNFeuJ0sKuXOIygJMlppRaq4hwZA3A" style="color: rgb(17, 85, 204);" class=""><span style="font-stretch: normal; line-height: normal;" class=""><b class="">running hotter</b></span></a></span><span style="color: rgb(55, 88, 138);" class=""><b class=""> </b></span><span style="font-kerning: none;" class="">than they have in the past. Soon the world could be, too.</span></span></p><p style="font-weight: normal; font-style: normal; font-family: Arial, Helvetica, sans-serif; font-variant-ligatures: normal; orphans: 2; widows: 2; margin: 0px 0px 15px; font-stretch: normal; line-height: normal; color: rgb(51, 51, 51);" class=""><span style="background-color: rgb(255, 255, 255);" class="">In earlier models, doubling atmospheric carbon dioxide (CO</span><span style="background-color: rgb(255, 255, 255); font-stretch: normal; line-height: normal;" class="">2</span><span style="background-color: rgb(255, 255, 255);" class="">) over preindustrial levels led models to predict somewhere between 2°C and 4.5°C of warming once the planet came into balance. </span></p><p style="font-weight: normal; font-style: normal; font-family: Arial, Helvetica, sans-serif; font-variant-ligatures: normal; orphans: 2; widows: 2; margin: 0px 0px 15px; font-stretch: normal; line-height: normal; color: rgb(51, 51, 51);" class=""><span style="background-color: rgb(255, 255, 255);" class="">But in </span><a href="https://cmip6workshop19.sciencesconf.org/data/CMIP6_CMIP6AnalysisWorkshop_Barcelona_190325_FINAL.pdf" target="_blank" data-saferedirecturl="https://www.google.com/url?q=https://cmip6workshop19.sciencesconf.org/data/CMIP6_CMIP6AnalysisWorkshop_Barcelona_190325_FINAL.pdf&source=gmail&ust=1569624414033000&usg=AFQjCNHEmtFEEfMwyf9ye46175ivGiLLUQ" style="background-color: rgb(255, 255, 255); color: rgb(17, 85, 204);" class=""><span style="font-stretch: normal; line-height: normal;" class=""><b class="">at least eight of the next-generation models</b></span></a><span style="background-color: rgb(255, 255, 255);" class="">, produced by leading centers in the United States, the United Kingdom, Canada, and France, that “equilibrium climate sensitivity” </span><span style="background-color: rgb(255, 251, 0);" class="">has come in at 5°C or warmer.</span><span style="background-color: rgb(255, 255, 255);" class=""> Modelers are struggling to identify which of their refinements explain this heightened sensitivity before the next assessment from the United Nations’s Intergovernmental Panel on Climate Change (IPCC). But the trend “is definitely real. There’s no question,” says Reto Knutti, a climate scientist at ETH Zurich in Switzerland. “Is that realistic or not? At this point, we don’t know.”</span></p><p style="font-weight: normal; font-style: normal; font-family: Arial, Helvetica, sans-serif; font-variant-ligatures: normal; orphans: 2; widows: 2; margin: 0px 0px 15px; font-stretch: normal; line-height: normal; color: rgb(51, 51, 51);" class=""><span style="background-color: rgb(255, 255, 255);" class="">That’s an urgent question: If the results are to be believed, the world has even less time than was thought to limit warming to 1.5°C or 2°C above preindustrial levels—a threshold many see as too dangerous to cross. With atmospheric CO2 already at 408 parts per million (ppm) and rising, up from preindustrial levels of 280 ppm, even previous scenarios suggested the world could warm 2°C within the next few decades. The new simulations are only now being discussed at meetings, and not all the numbers are in, so “it’s a bit too early to get wound up,” says John Fyfe, a climate scientist at the Canadian Centre for Climate Modelling and Analysis in Victoria, whose model is among those running much hotter than in the past. </span><span style="background-color: rgb(255, 251, 0);" class="">“But maybe we have to face a reality in the future that’s more pessimistic than it was in the past.”</span></p><div style="font-weight: normal; font-style: normal; font-family: Verdana; font-size: 14px;" class=""><span style="background-color: rgb(255, 251, 0);" class=""><br class=""></span></div></div></div></div></div>
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