Hotter, faster: Study finds global warming speeding up
Cain Burdeau
(CN) — The rate of global warming sped up considerably in the past decade, a finding that means a pivotal target set by the Paris Agreement may be exceeded even before 2030, according to a new study by researchers at a German climate institute.
The analysis by the Potsdam Institute for Climate Impact Research adds to a growing body of scientific literature suggesting global warming is accelerating, though there is still no consensus around this important debate. The paper was published Friday in Geophysical Research Letters.
“We can now demonstrate a strong and statistically significant acceleration of global warming since around 2015,” said Grant Foster, an American statistics expert and co-author.
Between 2015 and 2025, the researchers estimated the planet warmed by 0.35 degrees Celsius (0.68 degrees Fahrenheit), a significant jump from a steady rate of warming measured since 1970 of just under 0.2 C (0.36 F).
The past decade, then, was the fastest rate of warming since measurements began around 1880, the researchers said.
They did not seek to explain the reasons for the acceleration and instead focused on a statistical analysis to tease out whether warming is speeding up.
In recent years, James Hansen, a climate science pioneer and former NASA top scientist, focused minds on this matter by warning global warming was dangerously accelerating and cuts in greenhouse gas emissions were far too slow.
In a 2023 study, Hansen argued the rate of warming jumped by 50% since 2010. He linked the rising rate to efforts cutting pollution, which resulted in fewer particles in the atmosphere to reflect sunlight back into space. Those particles have a cooling effect.
The Potsdam Institute analysis helped back up Hansen’s warnings.
A scenario where warming is speeding up throws into question assumptions underpinning the Paris Agreement, the 2015 treaty setting out goals to reduce carbon emissions and keep warming to 1.5 C (2.7 F) more than the pre-industrial era.
“If the warming rate of the past 10 years continues, it would lead to a long-term exceedance of the 1.5 C limit of the Paris Agreement before 2030,” said Stefan Rahmstorf, a Potsdam Institute researcher who led the study.
Many scientists, including Hansen, believe the Paris Agreement’s goal of limiting warming to 1.5 C is unachievable and that the planet is facing a much warmer future.
In calculating the rate of warming, the Potsdam Institute researchers removed three key factors influencing global temperatures: the warming effect of El Niño weather events, volcanic eruptions and variations in solar intensity.
They said such short-term natural fluctuations “can mask changes in the long-term rate of warming.” After removing those factors, they said they obtained a global temperature curve that was less variable and thus found a statistically significant acceleration of global warming since 2015 across a range of temperature datasets.
“We filter out known natural influences in the observational data, so that the ‘noise’ is reduced, making the underlying long-term warming signal more clearly visible,” Foster said.
But their analysis was at odds with other recent statistical studies that showed no acceleration in warming at the global level.
“It is plausible that there has been an acceleration as the paper argues,” said Rebecca Killick, a statistics expert at both Lancaster University in England and Clemson University. Killick was part of a team that published a recent paper showing no acceleration.
But Killick said the Potsdam Institute paper fell short of proving the acceleration theory.
“Whilst some of the individual statistical methods employed in this paper are well vetted, their combination in this paper has not been shown to be reliable neither theoretically nor empirically,” said Killick and colleague Colin Gallagher, a Clemson University statistics expert, in an email.