Future Tipping

A study published in Science updates previous climate tipping point analyses. Greater amounts of warming lead to additional irreversible changes and any effort to reduce emissions matters.

Current global warming of ~1.1°C above pre-industrial already lies within the lower end of five CTP uncertainty ranges. Six CTPs become likely (with a further four possible) within the Paris Agreement range of 1.5 to <2°C warming, including collapse of the Greenland and West Antarctic ice sheets, die-off of low-latitude coral reefs, and widespread abrupt permafrost thaw. An additional CTP becomes likely and another three possible at the ~2.6°C of warming expected under current policies.

Currently the world is heading toward ~2 to 3°C of global warming; at best, if all net-zero pledges and nationally determined contributions are implemented it could reach just below 2°C. This would lower tipping point risks somewhat but would still be dangerous as it could trigger multiple climate tipping points.

Update (September 23):  Simon Clark calls it the "scariest climate science paper" he's read. 

Update (October 2):  The report Climate Dominoes published by Breakthrough - National Centre for Climate Restoration concludes:

At just 1.2°C of global average warming, tipping points have been passed for several large Earth systems. These include Arctic sea ice, the Greenland Ice Sheet, the Amundsen Sea glaciers in West Antarctica, the eastern Amazonian rainforest, and the world’s coral systems. The world will warm to 1.5°C by around 2030 with additional warming well beyond 1.5°C in the system after that. Yet even at the current level of warming, these systems will continue to move to qualitatively different states. In most cases, strong positive feedbacks are driving abrupt change. At higher levels of warming, the rate of change will quicken. The meme that "we have eight years to avoid 1.5°C and tipping points" should be deleted from the climate advocacy vocabulary. It is simply wrong: 1.5°C will be reached around 2030 regardless of the emissions path, and some tipping points are already here.

Update (December 12, 2023):  The Global Tipping Points report shows that five thresholds have been exceeded with three more possible if warming goes past 1.5 degrees Celsius.