Five potential breaking points. A warming of the planet beyond 1.5°C, the most ambitious objective of the Paris agreement, could trigger several “tipping points” climatic conditions that would cause 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 watch 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”, as defined by the UN Panel of Climate Experts (IPCC). These are phenomena that independently and ineluctably trigger other cascading consequences. The authors identify nine “tipping points” major at the planetary level and seven at the regional level, making 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 participate, over hundreds of years, in a rise in sea level of 10 meters. Another would cause a sudden thaw of the permafrost, which would release huge amounts 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.
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If initial analyzes estimated the threshold for triggering these tipping points in a range of 3 to 5°C of warming, progress in observations and climate modeling, as well as in the reconstruction of past climates, have drastically lowered this Evaluation. 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 breakpoints.