Overconfidence in climate overshoot

• 成果类型: Article
• 署名作者: Schleussner, Carl-Friedrich; Ganti, Gaurav; Lejeune, Quentin; Zhu, Biqing; Pfleiderer, Peter; Pruetz, Ruben; Ciais, Philippe; Froelicher, Thomas L.; Fuss, Sabine; Gasser, Thomas; Gidden, Matthew J.; Kropf, Chahan M.; Lacroix, Fabrice; Lamboll, Robin; Martyr, Rosanne; Maussion, Fabien; McCaughey, Jamie W.; Meinshausen, Malte; Mengel, Matthias; Nicholls, Zebedee; Quilcaille, Yann; Sanderson, Benjamin; Seneviratne, Sonia I.; Sillmann, Jana; Smith, Christopher J.; Steinert, Norman J.; Theokritoff, Emily; Warren, Rachel; Price, Jeff; Rogelj, Joeri
• 署名单位: International Institute for Applied Systems Analysis (IIASA); Humboldt University of Berlin; Humboldt University of Berlin; Universite Paris Saclay; University of Hamburg; Imperial College London; University of Bern; University of Bern; Potsdam Institut fur Klimafolgenforschung; Swiss Federal Institutes of Technology Domain; ETH Zurich; Federal Office of Meteorology & Climatology (MeteoSwiss); University of Bern; Imperial College London; University of Innsbruck; University of Bristol; University of Melbourne; Met Office - UK; Hadley Centre; University of Leeds; University of East Anglia; University of East Anglia
• 刊物名称: Nature
• ISSN/ISSBN: 0028-5319
• DOI: 10.1038/s41586-024-08020-9
• 发表日期: 2024-10-10
• 关键词: zero emissions; temperature; COMMITMENT; LIMITS

摘要

Global emission reduction efforts continue to be insufficient to meet the temperature goal of the Paris Agreement1. This makes the systematic exploration of so-called overshoot pathways that temporarily exceed a targeted global warming limit before drawing temperatures back down to safer levels a priority for science and policy2-5. Here we show that global and regional climate change and associated risks after an overshoot are different from a world that avoids it. We find that achieving declining global temperatures can limit long-term climate risks compared with a mere stabilization of global warming, including for sea-level rise and cryosphere changes. However, the possibility that global warming could be reversed many decades into the future might be of limited relevance for adaptation planning today. Temperature reversal could be undercut by strong Earth-system feedbacks resulting in high near-term and continuous long-term warming6,7. To hedge and protect against high-risk outcomes, we identify the geophysical need for a preventive carbon dioxide removal capacity of several hundred gigatonnes. Yet, technical, economic and sustainability considerations may limit the realization of carbon dioxide removal deployment at such scales8,9. Therefore, we cannot be confident that temperature decline after overshoot is achievable within the timescales expected today. Only rapid near-term emission reductions are effective in reducing climate risks. Aiming for declining global temperatures can limit long-term climate risks compared with a mere stabilization of global warming, including sea-level rise and cryosphere changes.