Global warming: several points of no return could be quickly reached, according to a study – franceinfo

Five potential breaking points. Global warming above 1.5°C, the most ambitious goal of the Paris Agreement, could trigger several climate “tipping points” that would trigger catastrophic chain reactions, according to a study published Friday, September 9 in the journal Science. According to the study, the current temperatures, already rising, threaten to initiate five of these points of failure, including those concerning the ice sheets of Antarctica and Greenland, warn the authors of the study, who estimate however that it is not too late to act. “For me, it will change the face of the world – literally, if you look from space”, with the rise in the level of the oceans or the destruction of the forests, explained to AFP Tim Lenton, one of the main authors of the study. A “tipping point” is “a critical threshold beyond which a system reorganizes, often brutally and/or irreversibly”, according to the definition of the UN Climate Panel (IPCC). These are phenomena that independently and ineluctably trigger other cascading consequences. The authors identify nine major “tipping points” at the planetary level and seven at the regional level, or 16 in total. Among these, five could be triggered with current temperatures, which have gained almost 1.2°C on average since the pre-industrial era. One of them concerns the ice caps in Antarctica and Greenland, and would participate, over hundreds of years, in a rise in sea level of 10 meters. Another would lead to a sudden thaw of permafrost, which would release immense quantities of greenhouse gases and profoundly change landscapes in Russia, Canada and Scandinavia. The study also mentions among these five tipping points the cessation of a heat transfer phenomenon in the Labrador Sea (in the Atlantic Ocean, between Labrador and Greenland) and the extinction of coral reefs. >> Visualize climate disruption over the past 30 years in five infographics While initial analyzes estimated the triggering threshold for these tipping points in a range of 3 to 5°C warming, progress in climate observations and modeling, as well as in the reconstruction of past climates, have drastically lowered this assessment. The study published in Science is a synthesis of more than 200 scientific publications, carried out in order to better predict the triggering thresholds of these breaking points.