Volcanic eruptions can have a powerful cooling effect on the Earth’s climate, but they’re notoriously difficult to predict. Most climate models assume a steady, average level of volcanic activity based on past records, rather than trying to account for the unpredictable nature of future eruptions. However, this approach doesn’t reflect reality—volcanic eruptions often happen in clusters or can go quiet for decades. Even smaller eruptions, which were often missed before satellite monitoring, contribute significantly to long-term climate impacts.

To improve climate projections, researchers have developed a new method that uses thousands of possible volcanic futures based on data from ice cores, satellite observations, and historical records. By feeding these scenarios into climate models, scientists can get a better picture of how future eruptions might affect global temperatures. Their findings show that volcanic activity could explain over a third of the uncertainty in near-term climate projections, even more than natural variability within the climate system.

Interestingly, the inclusion of realistic volcanic activity slightly reduces the chances of the world crossing 1.5°C of global warming in the short term, although it doesn’t affect the long-term picture. It also increases the chances of both cooler and hotter decades, which is important for planning around climate extremes. Volcanic eruptions don’t stop climate change—but they can temporarily mask its effects or make short-term predictions harder.

Climate models need to include these factors to better reflect the unpredictable nature of volcanic eruptions. The researchers suggest that future modelling projects, like those for the IPCC, should include more realistic volcanic scenarios to give us clearer insights into future climate risks and responses.

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