Permafrost warming could accelerate global warming

Permafrost extent in the northern hemisphere
Source: Hugo Ahlenius, UNEP/GRID-Arendal

Permafrost covers 15 million square km of the land surface and stores more than twice as much carbon as there is in the atmosphere. Conversion of part of this frozen carbon into carbon dioxide (CO2) and methane (CH4) into the atmosphere would accelerate the rate of climate change. In a recent study the spatial distribution of permafrost and air temperature is used to infer the sensitivity of permafrost to future global warming. It is estimated that the permafrost area loss for every degree Celsius (°C) of warming is 4 million square kilometers. Based on this sensitivity estimate, if the climate is stabilized at 2 °C above pre-industrial levels, it is estimated that the permafrost area would eventually be reduced by over 40% releasing as much carbon into the atmosphere as it currently contains. An observation-based constraint on permafrost loss as a function of global warming, S. E. Chadburn, E. J. Burke, P. M. Cox, P. Friedlingstein, G. Hugelius & S. Westermann, Nature Climate Change, 7, 340–344 (2017) doi:10.1038/nclimate3262