The Guardian
Giant ice sheets, ocean currents and permafrost regions may already have passed point of irreversible change.
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 study really underpins why the Paris agreement goal of 1.5C is so important and must be fought for.
“We’re not saying that, because we’re probably going to hit some tipping points, everything is lost and it’s game over. Every fraction of a degree that we stop beyond 1.5C reduces the likelihood of hitting more tipping points.” (...)
“Our new work provides compelling evidence that the world must radically accelerate decarbonising the economy. To achieve that, we need to trigger positive social tipping points.”
Complete article
The collapse of the Greenland ice cap is one of the tipping points that may already have been passed. Photograph: Ulrik Pedersen/Getty Images.
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