Thawing coastal permafrost in Arctic Canada (note person in photo for scale). Photo:Gustaf Hugelius.
Thawing coastal permafrost in Arctic Canada (note person in photo for scale). Photo:Gustaf Hugelius.
 

Permafrost is strongly affected by the implementation of climate change targets following the Paris COP21 agreement, according to a paper published in Nature Climate Change. The researchers from the UK, Sweden and Norway estimate that 4 million square kilometers of frozen ground (about nine times the size of Sweden) will be lost for each degree of global warming, with consequences for the emissions of greenhouse gases and the stability of buildings in high-latitude cities.​

On the one hand the news is rather bleak, as stabilising the climate at 2ºC above pre-industrial levels would lead to thawing of more than 40% of the current-day permafrost areas. However, as the lead-author Sarah Chadburn of the University of Leeds explains, “a lower stabilisation target of 1.5ºC, would save approximately 2 million square kilometres of permafrost”. The study therefore provides invaluable guidance to policymakers on the differing impacts of climate stabilisation at different levels of global warming.

The Arctic is warming twice as fast as the rest of the world, and permafrost is already starting to thaw over large areas of the land. But just how much permafrost will be lost as the planet warms up? This is an important question that scientists have struggled to answer. Using a novel combination of global climate models and observed data, the researchers devised a robust way to estimate the global loss of permafrost.

As co-author Gustaf Hugelius of Stockholm University explains “we used existing knowledge of how air temperature controls permafrost distribution to reveal the future sensitivity of permafrost to global warming”. They looked at the way that permafrost changes across the landscape, and how this is related to the air temperature. They then considered possible increases in air temperature in the future, and converted these to a permafrost distribution using their observation-based relationship. This allowed them to calculate the amount of permafrost that would be lost under proposed climate stabilisation targets.

Thawing permafrost in Siberian polygonal tundra. Photo: Gustaf Hugelius.
Thawing permafrost in Siberian polygonal tundra. Photo: Gustaf Hugelius.