9 September 2022 | David I. Armstrong McKay*, Arie Staal, Jesse F. Abrams, Ricarda Winkelmann, Boris Sakschewski, Sina Loriani, Ingo Fetzer, Sarah E. Cornell, Johan Rockström, Timothy M. Lenton*
The article "Exceeding 1.5°C Global Warming Could Trigger Multiple Climate Tipping Points" by David I. Armstrong McKay et al. reviews the current understanding of climate tipping points (CTPs) and their potential impacts. CTPs are critical thresholds in the climate system that, once crossed, can lead to self-perpetuating changes with significant and widespread consequences. The authors reassess nine global "core" tipping elements and seven regional "impact" tipping elements, identifying their estimated CTP thresholds and the timescales and impacts of tipping. They find that current global warming of ~1.1°C already lies within the lower end of five CTP uncertainty ranges, and six CTPs become likely (with four possible) within the Paris Agreement range of 1.5 to <2°C warming. These include the collapse of the Greenland and West Antarctic ice sheets, die-off of low-latitude coral reefs, and widespread abrupt permafrost thaw. The authors conclude that even the Paris Agreement goal of limiting warming to well below 2°C is not safe, as 1.5°C and above risks crossing multiple tipping points. They emphasize the urgency of mitigation efforts to prevent these tipping points from being triggered, as they could lead to positive feedback loops that further amplify global warming.The article "Exceeding 1.5°C Global Warming Could Trigger Multiple Climate Tipping Points" by David I. Armstrong McKay et al. reviews the current understanding of climate tipping points (CTPs) and their potential impacts. CTPs are critical thresholds in the climate system that, once crossed, can lead to self-perpetuating changes with significant and widespread consequences. The authors reassess nine global "core" tipping elements and seven regional "impact" tipping elements, identifying their estimated CTP thresholds and the timescales and impacts of tipping. They find that current global warming of ~1.1°C already lies within the lower end of five CTP uncertainty ranges, and six CTPs become likely (with four possible) within the Paris Agreement range of 1.5 to <2°C warming. These include the collapse of the Greenland and West Antarctic ice sheets, die-off of low-latitude coral reefs, and widespread abrupt permafrost thaw. The authors conclude that even the Paris Agreement goal of limiting warming to well below 2°C is not safe, as 1.5°C and above risks crossing multiple tipping points. They emphasize the urgency of mitigation efforts to prevent these tipping points from being triggered, as they could lead to positive feedback loops that further amplify global warming.