Earth’s global warming pace has accelerated significantly since around 2015, rising at an estimated 0.35°C per decade. Researchers analyzing five major temperature datasets report a statistical certainty of over 98 percent, warning that the long-term 1.5°C Paris Agreement limit could be breached before 2030.
How Scientists Confirmed the Global Warming Acceleration
For decades, the rise in Earth’s average temperature appeared to follow a relatively stable upward path. While individual years stood out due to strong El Niño episodes or volcanic eruptions, the broader trend remained steady as per the study published in Geophysical Research Letters, titled Global Warming Has Accelerated Significantly
. That picture is now changing because researchers have successfully separated long-term trends from short-term fluctuations.
Scientists Isolate the Long-Term Warming Signal 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 published today 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.
To achieve this, the research team adjusted temperature records by removing the estimated effects of El Niño, volcanic eruptions, and solar activity variations. This statistical filtering revealed a near doubling in the rate of warming. Following the strong 1998 El Niño, some previously claimed global warming had paused, but subsequent research proved that apparent halt merely reflected temporary natural variability superimposed on the long-term warming trend.
Five Datasets and Two Statistical Approaches Point to 2015
Rather than relying on a single source of data, the analysis evaluated five widely used global temperature records compiled by NASA, NOAA, HadCRUT, Berkeley Earth, and the ERA5 reanalysis across all five temperature data sets. The acceleration appeared consistently across all five independent records, independent of the analysis method chosen.
The research team deployed two distinct statistical methods to verify the shift. The first approach was a quadratic trend analysis, which tests whether the temperature curve bends upward over time rather than rising constantly. The second method was a piecewise linear model, which divides the temperature record into separate periods to objectively identify when the rate of warming changes. Both methods confirmed that the acceleration emerged around 2013 or 2014, with the broader shift becoming clear by 2015 as the evidence became clearer.
The adjusted data show an acceleration of global warming since 2015 with a statistical certainty of over 98 percent,
explains Stefan Rahmstorf, PIK researcher and lead author of the study at the Potsdam Institute for Climate Impact Research.
Accelerating Rates and the Shrinking Timeline to 1.5°C
The numbers highlight a sharp departure from historical warming rates. Over the past decade, global temperatures rose at an estimated pace of 0.35°C (0.63 degrees Fahrenheit) per decade. By comparison, the average warming rate from 1970 to 2015 was just under 0.2°C (0.36 degrees Fahrenheit) per decade as opposed to just under 0.36 degrees F.
This increased velocity brings critical climate thresholds into dangerously close view. While a single warm year does not formally breach the Paris Agreement—which requires sustained anomalies over a longer average—the trajectory is alarming. 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 warned in a statement regarding the 1.5°C limit.
What the Study Does Not Explain About the Causes
While the analysis provides robust statistical confirmation that warming has sped up, the authors emphasize that the study was not designed to determine the precise physical causes behind the inflection point. Climate models demonstrate that an increasing rate of warming falls within the range of expected behaviors under continued greenhouse gas emissions, but exact drivers remain debated.
Existing research suggests that declining atmospheric aerosol pollution may have reduced part of the cooling effect that previously offset greenhouse warming, though uncertainty persists regarding the exact magnitude of that contribution over the size of that contribution. Despite these open questions, the data rules out random weather variability or short-term El Niño spikes as the sole explanation for the recent heat.
The Path Ahead and the Limits of Reversal
Sustained temperature overshoots risk triggering severe tipping points, including ocean circulation breakdowns, permafrost thawing, and tropical coral reef collapses. Preventing further escalation ultimately ties back to immediate policy choices made by the world’s largest emitters, including the United States including the U.S..
“Stopping this trend is in our hands. Studies show that global warming will stop around the time humanity reaches zero CO2 emissions, but it can hardly be reversed.”
Grant Foster and Stefan Rahmstorf, Study Authors
Whether global policymakers will alter course before the end of the decade remains entirely uncertain, leaving the planet on a direct collision course with the critical 1.5°C threshold.
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