Global warming has sped up since around 2015, according to a new analysis from the Potsdam Institute for Climate Impact Research (PIK).
After removing the effects of natural temperature swings, researchers found the first statistically significant evidence that the planet’s long-term warming rate is accelerating. Over the past decade, global temperatures have risen at an estimated pace of about 0.35°C per decade, depending on the dataset used.
By comparison, the average warming rate from 1970 to 2015 was just under 0.2°C per decade. The recent pace is higher than that of any previous decade since instrumental temperature records began in 1880, a report obtained from Science Daily said.
Scientists, however, isolated the long-term warming signal, noting that, “We can now demonstrate a strong and statistically significant acceleration of global warming since around 2015,” says Grant Foster, a US statistics expert and co-author of the study, which was published in the scientific journal Geophysical Research Letters.
“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 added.
In climate data, “noise” refers to short-term temperature changes that can temporarily hide or exaggerate the underlying trend. El Niño, for example, can push global temperatures higher for a limited period by releasing heat from the tropical Pacific Ocean into the atmosphere. Volcanic eruptions can have the opposite effect by sending particles into the atmosphere that reflect sunlight, while changes in the Sun’s activity can also produce smaller temperature variations.
To separate these temporary influences from the broader warming trend, the researchers analyzed measurements from five widely used global temperature data sets (NASA, NOAA, HadCRUT, Berkeley Earth, ERA5).
“The adjusted data show an acceleration of global warming since 2015 with a statistical certainty of over 98 percent, consistent across all data sets examined and independent of the analysis method chosen,” explains Stefan Rahmstorf, PIK researcher and lead author of the study.
A statistical certainty of more than 98 percent means the researchers found strong evidence that the change in the warming rate is real rather than the result of random variation in the data. The same overall pattern appeared in all five temperature records, even though the datasets are produced by different scientific organizations and use somewhat different methods.
After the researchers adjusted for El Niño and the solar maximum, the extreme warmth of 2023 and 2024 was reduced slightly in the analysis. Even so, both years remained the two warmest since instrumental records began.
Across all of the datasets, the acceleration started to become visible in 2013 or 2014. The researchers describe the broader shift as beginning around 2015, when the evidence became clearer.
