Year: 2026
Type: article
Abstract: Overshooting global warming targets risks irreversible Earth system changes. However, uncertainties remain in how critical Earth system components such as permafrost and the Atlantic Meridional Overturning Circulation (AMOC) respond to and interact under warming. By using three climate models of varying complexity to assess the permafrost carbon response under idealized climate mitigation and overshoot scenarios, we here show that permafrost loses 11–21 PgC of carbon per 100 degree-years of warming exposure (cumulative warming over 100 years) during temperature overshoot in a robust linear relationship. This relationship also holds true under relative Northern Hemisphere cooling from a temporary AMOC slowdown during temperature overshoot. This relative cooling partially offsets climate change impacts on permafrost, while in itself causing adverse impacts on climate and society. These results underscore the importance of including both destabilizing and stabilizing Earth system feedbacks when assessing overshoot impacts, critical for informing carbon budgets, net-zero planning, and climate change reversibility. Climate models show permafrost carbon emissions scale linearly with warming exposure during temperature overshoot, also when AMOC-driven cooling partly offsets them. These climate feedbacks are crucial for carbon budgets and net-zero planning.
Source: Nature Communications
Institutions: Bjerknes Centre for Climate Research, NORCE Research AS, CICERO Center for International Climate Research, Met Office, International Institute for Applied Systems Analysis, University of Oxford, University of Leeds, Seoul National University, Norwegian University of Science and Technology
Language: English
Subfield: Atmospheric Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Climate action
Open Access status: gold
Estimated APC paid: $6,990
OpenAlex ID: W7168581905