Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research says global warming has accelerated since around 2015, and the team’s adjusted data put that shift at more than 98 percent statistical certainty. The study, published in Geophysical Research Letters, says the faster rise shows up after removing natural temperature swings from five global records.
Rahmstorf said the evidence became clearer around 2015. The analysis puts the recent warming pace at about 0.35°C per decade, compared with just under 0.2°C per decade from 1970 to 2015, making it the fastest decade in the instrumental record that began in 1880.
Geophysical Research Letters study
The researchers analyzed data from NASA, NOAA, HadCRUT, Berkeley Earth and ERA5. The same overall pattern appeared in all five records, and the team used both a quadratic trend analysis and a piecewise linear model to test whether the warming rate had changed since the 1970s.
Grant Foster, a US statistics expert and co-author of the study, said, “We can now demonstrate a strong and statistically significant acceleration of global warming since around 2015,” and added, “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,”
NASA NOAA HadCRUT
The adjustment step matters because the researchers were not looking at short-lived spikes alone. After removing effects tied to El Niño and the solar maximum, the extreme warmth of 2023 and 2024 was reduced slightly in the analysis, but both years still ranked as the two warmest since instrumental records began.
Across the datasets, the acceleration started to become visible in 2013 or 2014, and the broader shift became clearer around 2015. Rahmstorf said, “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,”
Berkeley Earth and ERA5
The practical takeaway for anyone following climate trend data is that the recent warming pace is no longer sitting near the long-term average. The study says the newer rate is higher than any previous decade since 1880, so trend lines built on older baselines now understate how fast temperatures have been rising since the mid-2010s.
The open question is what is driving the faster rate since around 2015 after the natural swings were stripped out. This study does not answer that part; it says the signal is now visible in five widely used records, and that leaves the cause for the next round of analysis.
