Global warming has accelerated significantly since 2015, rising at an estimated pace of about 0.35 degrees Celsius per decade. Researchers at the Potsdam Institute for Climate Impact Research report a statistical certainty of over 98 percent that long-term warming has sped up, threatening to push past the Paris Agreement limit before 2030.
Earth’s long-term temperature rise is no longer moving at a steady pace. Following a thorough statistical analysis of observational data, scientists have documented the first statistically significant evidence that the planet’s warming rate has kicked into a faster gear. Over the past decade, global temperatures have climbed at an estimated pace of roughly 0.35 degrees Celsius per decade, depending on the dataset examined. That speed marks a sharp departure from the average warming rate of just under 0.2 degrees Celsius per decade recorded between 1970 and 2015.
Isolating the Long-Term Warming Signal From Natural Noise
Telling natural, short-term fluctuations apart from long-term trends driven by human activity has long presented a statistical challenge in climate science. Natural variability has created misleading conclusions in the past. Following the strong 1998 El Niño, for example, some observers claimed that global warming had slowed or even stopped. Subsequent research demonstrated that the apparent pause reflected temporary natural variability superimposed on the long-term trend rather than a halt in anthropogenic warming.
To answer whether the rate of human-caused warming has actually changed in recent years, researchers analyzed measurements from five widely used global temperature datasets: NASA, NOAA, HadCRUT, Berkeley Earth, and ERA5. The team applied two statistical approaches—a quadratic trend analysis to test whether the temperature curve is bending upward over time, and a piecewise linear model to objectively identify when the rate of warming changes.
“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.”
Grant Foster, US statistics expert and co-author
After adjusting for natural influences such as El Niño, volcanic eruptions, and solar variation, the team found that the acceleration appeared consistently across all five temperature records. The adjusted data show an acceleration of global warming since 2015 with a statistical certainty of over 98 percent, according to Stefan Rahmstorf, a researcher at the Potsdam Institute for Climate Impact Research and lead author of the study published in Geophysical Research Letters.
Implications for the 1.5-Degree Celsius Paris Agreement Limit
While the study was designed to detect and measure statistical acceleration rather than determine its exact causes, the authors noted that climate models can produce periods in which warming speeds up. Even after researchers adjusted for El Niño and the solar maximum, the extreme warmth of 2023 and 2024 remained the two warmest years since instrumental records began around 1880, though those peak temperatures were reduced slightly in the analysis.
This heightened pace puts global temperature records on a trajectory to cross critical thresholds much sooner than previously anticipated. Officially breaching the Paris Agreement limit requires global temperatures to exceed 1.5 degrees Celsius above pre-industrial levels for an average of 20 years.
“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.”
Stefan Rahmstorf, Potsdam Institute for Climate Impact Research
Long-term exceedance of that threshold could trigger multiple climate tipping points. These changes could include breakdowns of major ocean circulation systems, abrupt thawing of boreal permafrost, and the collapse of tropical coral reef systems, carrying irreversible consequences for humanity.
Emissions Reductions and the Path Ahead
The findings underscore how insufficient efforts to slow and eventually stop global warming under international climate accords have been. Without decisive action from major polluters, including the United States, the current pace of warming is projected to continue or accelerate further.
The researchers emphasize that stopping the upward trajectory remains entirely within human control, contingent on the speed of decarbonization.
“How quickly the Earth continues to warm ultimately depends on how rapidly we reduce global CO2 emissions from fossil fuels to zero.”
Stefan Rahmstorf, Potsdam Institute for Climate Impact Research
