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CL3.2.5 | Temperature overshoot and climate (ir)reversibility
EDI
Temperature overshoot and climate (ir)reversibility
Convener: Carl-Friedrich Schleussner | Co-conveners: Biqing ZhuECSECS, Fabien MaussionECSECS
The Paris Agreement long-term temperature goal of limiting warming to 1.5°C sets ambitions for global climate action to avoid the most devastating impacts of climate change. However, due to past and present climate inaction, exceeding a global mean temperature increase of 1.5°C above pre-industrial levels is a distinct possibility. This has led to an increased interest in so-called overshoot pathways that exceed a global warming level before returning to or below it in the long-run, commonly by deploying net-negative carbon dioxide removal at scale.

The prospects of such a global temperature overshoot raise important questions in relation to Earth system feedbacks under overshoot, and the feasibility and side-effects of large-scale deployment of carbon dioxide removal. Regional and sector specific climate and climate impact evolution under long-term global temperature decline and resulting implications for adaptation needs are poorly understood. Potential irreversibilities and hysteresis behavior of climate impacts under overshoot are a key research gap.

In this session, we welcome abstract submissions on global climate dynamics under peak and decline pathways, on regional to global climate impacts in overshoot scenarios, and mechanisms of non-linearity under global warming reversal. We also invite analysis focussing on consequences in a wide range of sectors, from ocean dynamics to the cryosphere, biodiversity and biosphere changes to human systems and economic consequences of overshoot. Contributions that consider the socio-economic conditions and feasibility of overshoot scenarios, climate effects of large scale carbon dioxide removal, as well as the implications of overshoots for climate change adaptation planning are also strongly encouraged.