14 April 2016, The Guardian, World’s scientists to join forces on major 1.5C climate change report. Special UN report will offer comprehensive assessment of impacts of a 1.5C rise in global warming on sea level, coral bleaching and biodiversity. Scientists from around the world will contribute to a major UN report on how global temperatures can be held to a rise of 1.5C and what the impact might be on sea level rises, the bleaching of corals and biodiversity. The special report, from the Intergovernmental Panel on Climate Change (IPCC), will assess all the available peer-reviewed science along with other special reports on how land and oceans are being affected by climate change. These will look at the melting of ice in polar and mountain regions, as well as the impact of climate change on cities and food supplies. “We now have a roadmap for the next comprehensive assessment which will be published in 2022, in good time for the global stocktake by governments in 2023,” said Hoesung Lee, chair of the panel, in Nairobi. The 1.5C report was requested by governments meeting at the Paris climate talks in December where countries unexpectedly agreed to “pursue efforts” to limit warming to 1.5C above pre-industrial levels. 1.5C marks the point, say many scientists, where there is a real danger of serious “tipping points” in the world’s climate. Temperatures have already risen 1C and show little sign of slowing. “Before the Paris meeting governments were focussing on [a rise of ] 2C. The latest assessment by the IPCC showed that some serious risks to corals and sea-level rise emerge at 1.5C. But there was not much available [science] on these topics. There is a lot we need to find out about 1.5C. We are ready to embark on this,” said Lee. “Limiting warming to 1.5C will be a significant challenge,” said Myles Allen, Professor of Geosystem Science at Oxford university’s Environmental Change Institute (ECI). “In a nutshell, it means we have to reduce emissions twice as fast as we would have done to limit warming to 2C – and that was already looking challenging. Inevitably, people are already starting to ask if it is worth it. These are big tough questions, and we haven’t much time to answer them, so the academic community needs to step up.” Read More here
Category Archives: Impacts Observed & Projected
13 April 2016, The Guardian, It’s settled: 90–100% of climate experts agree on human-caused global warming. There is an overwhelming expert scientific consensus on human-caused global warming. Authors of seven previous climate consensus studies — including Naomi Oreskes,Peter Doran, William Anderegg, Bart Verheggen, Ed Maibach, J. Stuart Carlton,John Cook, myself, and six of our colleagues — have co-authored a new paper that should settle this question once and for all. The two key conclusions from the paper are:
1) Depending on exactly how you measure the expert consensus, it’s somewhere between 90% and 100% that agree humans are responsible for climate change, with most of our studies finding 97% consensus among publishing climate scientists.
2) The greater the climate expertise among those surveyed, the higher the consensus on human-caused global warming.
Expert consensus is a powerful thing. People know we don’t have the time or capacity to learn about everything, and so we frequently defer to the conclusions of experts. It’s why we visit doctors when we’re ill. The same is true of climate change: most people defer to the expert consensus of climate scientists. Crucially, as we note in our paper: Public perception of the scientific consensus has been found to be a gateway belief, affecting other climate beliefs and attitudes including policy support. Read More here
11 April 2016, Springer Link, Significant implications of permafrost thawing for climate change control. Large amounts of carbon are stored as permafrost within the Arctic and sub-Arctic regions. As permafrost thaws due to climate warming, carbon dioxide and methane are released. Recent studies indicate that the pool of carbon susceptible to future thaw is higher than was previously thought and that more carbon could be released by 2100, even under low emission pathways. We use an integrated model of the climate and the economy to study how including these new estimates influence the control of climate change to levels that will likely keep the temperature increase below 2 °C (radiative forcing of 2.6 Wm−2). According to our simulations, the fossil fuel and industrial CO2 emissions need to peak 5–10 years earlier and the carbon budget needs to be reduced by 6–17 % to offset this additional source of warming. The required increase in carbon price implies a 6–21 % higher mitigation cost to society compared to a situation where emissions from permafrost are not considered. Including other positive climate feedbacks, currently not accounted for in integrated assessment models, could further increase these numbers. Read More here
7 April 2016, Carbon Brief, Analysis: the ‘highly unusual’ behaviour of Arctic sea ice in 2016. The decline of Arctic sea ice is already setting records in 2016, with the winter peak in March clocking in as the lowest since satellite records began, scientists say. A new and fuller summary of this year’s Arctic winter by the US National Snow and Ice Data Centre (NSIDC) confirms the preliminary announcement last week that sea icereached its annual maximum extent on 24 March this year. Covering an area of 14.52m square kilometers, this year’s peak winter extent is a shade smaller than the previous record low set in 2015. But the new NSIDC report adds a lot more detail about what it calls a “highly unusual” and “most interesting” Arctic winter. With abnormally warm conditions right across the Arctic, some regions experienced temperatures 4-8C higher than average. While this meant slower ice growth in some places, in others it caused a dramatic thinning by 30cm in one week, according to early model results. Reaching a peak Arctic sea ice ebbs and flows with the seasons, reaching a maximum extent for the year in February or March and a minimum in September, at the end of the summer melt period. This year, scientists were still waiting expectantly at the end of March, explains the NSIDC report: “Very early in the month, extent declined, raising anticipation that an early maximum had been reached. However, after a period of little change, extent slowly rose again, reaching the seasonal maximum on March 24.” As late as a week ago, scientists still hadn’t ruled out the possibility of a late season surge. But sea ice extent has dropped off quite a bit since then, suggesting the peak has been and gone. You can see this year’s sea ice behaviour in the graph below from NSIDC, which shows sea ice extent over the 2015/6 winter (blue line) up to 3 April compared to previous years. Read More here