Acceleration of permafrost thaw

Permafrost, i.e. permanently frozen ground, stores about twice as much carbon as the atmosphere. The climate-induced thawing of permafrost has to potential to release huge amounts of greenhouse gases to the atmosphere, representing one of the strongest positive climate feedbacks. Current models, as discussed in the IPCC 5th assessment report, cannot predict the strength of this feedback with confidence because the rate of thawing of permafrost involves complex processes and feedbacks that are not described and because the frozen carbon reservoir is not treated in sufficient detail. We have identified strong positive feedbacks between snow and vegetation that are likely to accelerate permafrost thaw, because increasing shrub cover in the Arctic enhances the thermal insulation properties of the snow cover.

A French-Canadian consortium has been assembled to develop experimental and modeling approaches to reach the following objectives: (1) predict the permafrost thermal regime, while accounting for these novel feedbacks; (2) predict greenhouse gas emissions by thawing permafrost and quantify the permafrost-climate feedback. The project will benefit from the coordinator’s position within the joint research laboratory Takuvik created between CNRS and Université Laval in Quebec City.