Global warming acceleration has been detected since around 2015, according to a peer-reviewed analysis that separated the long-term temperature trend from shorter natural fluctuations. Researchers estimated that Earth warmed at roughly 0.35°C per decade over the most recent 10-year period, compared with just under 0.2°C per decade on average between 1970 and 2015.
The study was led by climate scientist Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research and statistician Grant Foster. It was published in Geophysical Research Letters in March 2026. The research is receiving renewed attention after being republished in an August science report, but it should not be described as a newly released August study.
Scientists Remove Natural Temperature Variations
Year-to-year global temperatures are affected by natural influences that can temporarily strengthen or weaken the apparent warming trend. El Niño can raise global temperatures by releasing heat from the tropical Pacific, major volcanic eruptions can cool the planet by reflecting sunlight, and changes in solar activity can create smaller variations.
The researchers estimated and removed the influence of El Niño, volcanism and solar variation from five major global temperature records. The datasets were produced by NASA, NOAA, HadCRUT, Berkeley Earth and the European Centre for Medium-Range Weather Forecasts through its ERA5 reanalysis.
After those adjustments, all five datasets showed evidence that the warming rate had increased. The study reported statistical confidence above 98 per cent, meaning the acceleration was unlikely to be explained by random variation alone. The pattern remained visible regardless of which dataset or statistical method the researchers used.
Two Methods Identify a Similar Shift
The team applied two approaches to determine whether warming had departed from the earlier trend. A quadratic analysis tested whether the temperature curve was bending upward over time. A piecewise linear model allowed the researchers to identify a point at which the warming rate changed.
Both approaches supported acceleration. The change became visible around 2013 or 2014 in several records, while the researchers described the broader shift as beginning around 2015. They also found that the result was not driven only by the exceptional warmth recorded in 2023 and 2024.
Those two years became slightly less extreme after the influence of El Niño and the solar maximum was removed, but they remained the warmest years in the instrumental record examined by the researchers. The estimated recent rate was also higher than that of any earlier decade since modern global temperature observations began in 1880.
Study Does Not Establish the Cause
The research was designed to detect and measure acceleration, not determine exactly why it occurred. The authors noted that climate models can produce periods of faster warming and discussed declining aerosol cooling as one possible explanation examined by other scientists, but the analysis did not establish a single cause.
That distinction matters because removing natural variability reveals the underlying trend without automatically identifying every physical influence responsible for the change. Human activities, principally greenhouse gas emissions, have unequivocally caused long-term global warming, while aerosols, ocean conditions and natural variability can influence the rate over shorter periods.
Paris Threshold Could Be Exceeded Before 2030
Rahmstorf said that if the estimated warming rate of the past decade continues, long-term warming could exceed 1.5°C above pre-industrial levels before 2030. The statement is conditional and does not mean the threshold has already been permanently crossed.
A single year above 1.5°C is not treated as a lasting breach of the Paris Agreement goal. Scientists generally assess the threshold using sustained warming over a longer period because individual years can be pushed higher or lower by natural variability.
The future rate of warming will depend heavily on carbon dioxide emissions from fossil fuels. The study’s findings provide strong evidence of global warming acceleration since around 2015, while also showing that the pace of future change remains closely tied to how rapidly emissions are reduced