From The Guardian, Damian Carrington, September 8, 2022
The climate crisis has driven the world to the brink of multiple “disastrous” tipping points, according to a major study.
It shows five dangerous tipping points may already have been passed due to the 1.1C of global heating caused by humanity to date.
These include the collapse of Greenland’s ice cap, eventually producing a huge sea level rise, the collapse of a key current in the north Atlantic, disrupting rain upon which billions of people depend for food, and an abrupt melting of carbon-rich permafrost.
At 1.5C of heating, the minimum rise now expected, four of the five tipping points move from being possible to likely, the analysis said. Also at 1.5C, an additional five tipping points become possible, including changes to vast northern forests and the loss of almost all mountain glaciers.
In total, the researchers found evidence for 16 tipping points, with the final six requiring global heating of at least 2C to be triggered, according to the scientists’ estimations. The tipping points would take effect on timescales varying from a few years to centuries.
“The Earth may have left a ‘safe’ climate state beyond 1C global warming,” the researchers concluded, with the whole of human civilisation having developed in temperatures below this level. Passing one tipping point is often likely to help trigger others, producing cascades. But this is still being studied and was not included, meaning the analysis may present the minimum danger.
Prof Johan Rockström, the director of the Potsdam Institute for Climate Impact Research, who was part of the study team, said: “The world is heading towards 2-3C of global warming.