Global warming will thaw more permafrost than previously thought

The UK Met Office reports that “global warming will thaw about 20 per cent more permafrost than previously thought, scientists have warned – potentially releasing significant amounts of greenhouse gases into the Earth’s atmosphere. A new international research study, including climate change experts from the University of Leeds, University of Exeter and the Met Office, reveals that permafrost is more sensitive to the effects of global warming than previously thought. The study, published in Nature Climate Change, suggests that nearly 4 million square kilometres of frozen soil – an area larger than India – could be lost for every additional degree of global warming experienced. Permafrost is frozen soil that has been at a temperature of below 0°C for at least two years. Large quantities of carbon are stored in organic matter trapped in the icy permafrost soils. When permafrost thaws the organic matter starts to decompose, releasing greenhouse gases such as carbon dioxide and methane which increase global temperatures. It is estimated that there is more carbon contained in the frozen permafrost than is currently in the atmosphere.”

“Recent studies have shown that the Arctic is warming at around twice the rate as the rest of the world, with permafrost already starting to thaw across large areas. The researchers, from Sweden and Norway as well as the UK, suggest that the huge permafrost losses could be averted if ambitious global climate targets are met. Lead-author Dr Sarah Chadburn of the University of Leeds said: ‘A lower stabilisation target of 1.5°C would save approximately two million square kilometres of permafrost. Achieving the ambitious Paris Agreement climate targets could limit permafrost loss. For the first time we have calculated how much could be saved.’”

“This allowed them to calculate the amount of permafrost that would be lost under proposed climate stabilisation targets. As co-author Professor Peter Cox of the University of Exeter explained: ‘We found that the current pattern of permafrost reveals the sensitivity of permafrost to global warming.’ The study suggests that permafrost is more susceptible to global warming than previously thought, as stabilising the climate at 2°C above pre-industrial levels would lead to thawing of more than 40 per cent of today’s permafrost areas.”

Source: http://www.metoffice.gov.uk/news/releases/2017/climate-targets-to-constr...