Global Warming Has Accelerated Since 2015, Potsdam Study Finds, With Rate Near 0.35°C a Decade

Researchers at the Potsdam Institute report statistically significant evidence that Earth's warming rate has risen since about 2015, even after removing El Niño, volcanic and solar effects.

A new study from the Potsdam Institute for Climate Impact Research (PIK), published in Geophysical Research Letters, reports the first statistically significant evidence that the pace of global warming has increased since around 2015. The authors estimate that the planet has warmed by roughly 0.35°C per decade over the past ten years, although the exact figure depends on the temperature dataset used. That compares with an average of just under 0.2°C per decade between 1970 and 2015. Lead author Stefan Rahmstorf and co-author Grant Foster say the acceleration holds with a statistical certainty of more than 98 percent.

To test whether the jump was simply natural noise, the team adjusted observations for known influences such as El Niño, volcanic eruptions and the solar cycle. They analysed five major datasets (NASA, NOAA, HadCRUT, Berkeley Earth and ERA5) using two statistical approaches, a quadratic trend analysis and a piecewise linear model, and report consistent results in every case. Signs of the shift were already visible in 2013 or 2014, according to the researchers. After adjustment, 2023 and 2024 were somewhat cooler than the raw figures but still the warmest years since instrumental records began in 1880.

The study was not designed to explain why warming has sped up, and the authors stress that detecting a change in rate is different from identifying its physical causes. They add that the acceleration is consistent with what current climate models can produce. Rahmstorf warns that if the rate of the past decade continues, the long-term 1.5°C limit of the Paris Agreement would be exceeded before 2030, and that the pace ultimately depends on how quickly CO2 emissions from fossil fuels are cut to zero. The findings are based on the researchers' analysis and press materials, and the projection is conditional on the recent rate persisting.