Permafrost Carbon Emissions from a Warming Arctic: What are the Implications for International Climate Goals?
Abstract
Permafrost contains the largest vulnerable carbon pool on the planet, holding nearly twice the amount of carbon as is currently in the atmosphere. As the Arctic permafrost region continues to warm, this carbon pool is expected to become a significant source of emissions to the atmosphere. Despite the potential for a strong positive feedback to future climate change, permafrost emissions are rarely included in climate models, many of which will inform the Intergovernmental Panel on Climate Change 6 th Assessment Report. Critically, when models do incorporate permafrost emissions, thawing is simulated as a gradual top-down process—ignoring non-linear processes such as abrupt thaw and fire-permafrost interactions, which may have a similar or greater impact on our remaining carbon budgets. Therefore, there is an urgent need for a comprehensive assessment that links global climate change scenarios to carbon emissions from gradual thaw, abrupt thaw, and fire, and to assess the implications for carbon budgets that limit warming to the 1.5°C and 2°C temperature goals as outlined in the Paris Climate Agreement. To address this need, we developed a simple but robust modelling framework that builds upon the reduced complexity Earth System Model (OSCAR) and gradual permafrost thaw emulator by incorporating abrupt permafrost thaw, fire-carbon emissions, and fire-induced permafrost degradation. We found that the impact of permafrost thaw and fire emissions on global emissions budgets depended not only on the ultimate temperature target, but also on the pathway to these targets (i.e., the timing, as well as the magnitude, of anthropogenic emissions), with early mitigation of anthropogenic emissions associated with a larger remaining emissions budget. For the first time, we demonstrate the substantial emissions that may be released from the combined effects of gradual and abrupt permafrost thaw, fire, and post-fire thaw from the Arctic permafrost region, which will dramatically reduce the global emissions budgets that limit warming to 1.5°C and 2°C. Our conclusions underscore the urgency of international efforts to implement existing climate policy pledges and to accelerate ambition ahead of the next Conference of the Parties to the UN Framework Convention on Climate Change in 2021.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMB027...09T
- Keywords:
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- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCES;
- 0428 Carbon cycling;
- BIOGEOSCIENCES;
- 0702 Permafrost;
- CRYOSPHERE