The newest generation of climate models paints a stark picture: even at 1.5 °C of global warming, multiple parts of Earth’s climate system are already at risk of sudden, large-scale shifts.

In a recent ClimTip webinar, Sjoerd Terpstra (Utrecht University) presented results from the new systematic assessment of abrupt shifts in the CMIP6 model ensemble. Using “edge detection” method adapted from computer vision, Terpstra and colleagues traced when and where rapid changes appear in major climate subsystems such as sea ice, permafrost, snow cover, and forests.

Key findings

• Widespread abrupt shifts: 48 out of 57 models showed at least one large-scale abrupt shift.
• Risks already at 1.5 °C: At the Paris Agreement target, six out of ten subsystems showed abrupt shifts in multiple models.
• Systems most affected: Arctic summer and winter sea ice, Barents Sea ice, permafrost, Amazon rainforest, boreal forests, and snow cover on the Tibetan Plateau.
• Uncertainty remains high: Models disagree on exactly when and where shifts occur, but the pattern is consistent: the risk grows with warming.

Why this matters

Abrupt shifts are not the same as tipping points, but they signal rapid and sometimes unexpected changes compared to the recent past. The study shows that even well before higher warming levels are reached, critical parts of the Earth system can reorganize suddenly — challenging assumptions that changes will always be gradual.

The research builds on earlier CMIP5 assessments (Drijfhout et al., 2015; Bathiany et al., 2020), but goes further: using an automated detection method, linking shifts to warming thresholds, and mapping their spatial extent.

Importantly, the authors note that not all subsystems are represented in these simulations. For example, Greenland and Antarctic ice sheets are excluded. This means the results may understate the full picture of abrupt climate change.

Abrupt shifts appear in nearly every system analyzed. Concerningly, they emerge across a wide range of global warming levels, but some occur as early as 1.5 °C. As the authors put it:

“At a global warming of 1.5°C — which is a target set by the Paris climate agreement — six out of 10 studied climate subsystems showed large-scale abrupt shifts across multiple models.” – Terpstra et al. (2025)

Webinar Recording

Watch the full talk with the Q&A below or on our Youtube channel.

Speaker profile

Sjoerd Terpstra is an early career researcher with a bachelor’s in physics and a master’s in computational science. He is now a PhD candidate at Utrecht University, focusing on climate tipping points and their interactions.

Image credit (thumbnail and opener): Design by Kuat Abeshev. Photo by meriç tuna on Unsplash. Photo by David Lartey on Unsplash.

Add to your Watchlist

For more conversations like this, explore the ClimTip webinar series and see how science is tackling the biggest challenges of climate tipping points.

Watch the previous webinar with Levke Caesar on the Climate Tipping Points and the Planetary Boundaries Framwork.

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