Bleaching, Melting, Slowing: New report tracks growing risks of Earth system tipping points

Beyond coral reefs, the report highlights the risks, consequences, and governance challenges around Earth system tipping points. These span a variety of scales, from those with local impacts like glaciers and small ice fields to those with consequences at the continental and global scale, such as major ocean circulations, the polar ice sheets, and the Amazon rainforest. Current global warming of around 1.3-1.4 °C already exceeds the estimated tipping point for warm-water coral reefs. Several critical Earth system components, including land permafrost, the Greenland ice sheet, the West Antarctic ice sheet and the North Atlantic subpolar gyre, may reach their tipping points once temperatures rise just above 1.5 °C. 

“We have more and more evidence for tipping points in all these different systems”, warns PIK scientist Sina Loriani, who has co-led a new, updated section on the latest state of science on Earth system tipping points. “There is an increasing risk that we kick off feedback loops that amplify and accelerate changes in the Earth system.” 

The report finds that widespread die back of the Amazon rainforest, due to the combined stress of climate change and deforestation, could be triggered at a lower temperature than previously thought, with the lower end of the estimated range now at 1.5°C. This highlights the need for urgent action. “We must minimise both how far and how long we overshoot 1.5°C. Every fraction of a degree, and every year above that threshold, increases the risk of triggering irreversible tipping points,” says Nico Wunderling, scientist at PIK and Goethe University Frankfurt and also a report co-section lead. 

Case study underscores the outsized impact that crossing tipping points will have

A case study on Áakʼw Tʼáak Sítʼ, also known as the Mendenhall Glacier, near Juneau, Alaska (USA) highlights the substantial risks of crossing tipping points even in relatively small-scale systems like glaciers and small ice fields. In Juneau, increasingly large glacier lake outburst floods from Áakʼw Tʼáak Sítʼ set successive records in 2023, 2024 and 2025, causing tens of millions of dollars of damage and presenting serious adaptation and governance challenges for the region.

“The tragic situation in Juneau underscores the outsized impact that crossing tipping points will have on cities, local communities, and indigenous peoples everywhere, as they will bear the burden of adapting to continued environmental change. The quick and resilient actions of many – from building temporary flood barriers, to sourcing mutual aid and investing in long-term planning – demonstrate the complex network of stakeholder and rightsholder groups that must engage to achieve ‘real-world’ adaptation,” said PIK scientist Donovan Dennis, who led the case study. 

Not just warnings: the report identifies positive changes too

The 160 authors of the report argue that the nature of abrupt and irreversible Earth system tipping points mean they pose a different type of threat to other environmental challenges, and that current policies and decision-making processes are not currently adequate to respond.

However positive changes have been observed with the rapid up take of solar photovoltaics, wind power globally, and in the adoption of electric vehicles, battery storage and heat pumps in leading markets. The report shows that these technologies are already rapidly transforming energy systems, but further acceleration – e.g. via positive social and economical tipping points – is needed to halt and reverse global warming in time to avert triggering other tipping points.