Arctic permafrost carbon and global climate models

A policy-relevant review of the latest in Earth System Model development

As the Arctic rapidly warms, loss of permafrost (i.e., continuously frozen ground that underlies roughly 15% of the exposed land surface in the Northern Hemisphere and which contains an estimated 1.5 trillion tons of carbon) could release greenhouse gas (GHG) emissions (carbon dioxide and methane) at levels rivaling the highest-emitting countries. Accounting for these potential emissions is necessary to inform time-bound, tailored, and ambitious mitigation strategies that avoid the worst climate scenarios.

Unfortunately, Earth System Models (ESMs), which are used to understand planetary responses and feedbacks to future climate scenarios, currently do not include complete representation of the permafrost-carbon cycle*;  consequently, the global carbon budget underestimates potential GHG emissions from permafrost thaw and related feedbacks. Improved representation of permafrost carbon dynamics in ESMs will ultimately ensure that policy, innovation, and research are consistent with a  1.5°C climate threshold and other climate commitments (pursuant to national ambition and the Paris Agreement).