Potsdam Institute Researchers Detect Sharp Acceleration in Global Warming

Potsdam Institute Analysis Isolates Long-Term Warming Signal

Global temperatures are rising faster than they did during the final decades of the 20th century. According to a study from the Potsdam Institute for Climate Impact Research, the planet’s long-term warming rate has sped up notably since around 2015. After stripping away the noise of short-term weather fluctuations, investigators uncovered the first statistically significant evidence that the underlying warming trajectory is bending upward.

Over the past decade, global temperatures increased at an estimated pace of about 0.35°C per decade, depending on the dataset examined. That represents a sharp jump from the average warming rate recorded between 1970 and 2015, which sat just under 0.2°C per decade. This recent pace outstrips any comparable decade since instrumental record-keeping began in 1880.

“We can now demonstrate a strong and statistically significant acceleration of global warming since around 2015,”

Grant Foster, a US statistics expert and co-author of the study, via Sciencedaily

To strip away temporary distortions, the research team filtered out known natural influences. Natural variability can obscure long-term trajectories for years at a time. An El Niño event, for example, releases heat from the tropical Pacific Ocean into the atmosphere to spike global temperatures temporarily. Volcanic eruptions send sunlight-reflecting particles aloft to cool the planet, while solar activity fluctuations alter incoming energy.

By removing these factors, researchers made the underlying long-term signal more clearly visible in the observation records.

Consistent Findings Across Five Major Temperature Datasets

To ensure the trend was not an artifact of a single tracking system, the team evaluated five widely used global temperature records: NASA, NOAA, HadCRUT, Berkeley Earth, and ERA5. Even though these independent scientific organizations collect data using different methods, all five records displayed the same fundamental shift.

A statistical certainty of more than 98 percent indicates that the change in the warming rate reflects a real physical shift rather than random data variation. Even after the researchers adjusted their models to account for the extreme warmth driven by an El Niño and a solar maximum during 2023 and 2024, those two years remained the warmest in the instrumental record. Across the datasets, the inflection point became apparent in 2013 or 2014, with the broader shift firmly established by 2015.

To test the data rigorously, the authors deployed two distinct statistical methods. The first was a quadratic trend analysis, which evaluates whether the temperature curve bends upward rather than climbing linearly. The second was a piecewise linear model, designed to divide the temperature record and objectively pinpoint when the pace shifted. Both approaches confirmed the acceleration.

Paris Agreement 1.5°C Threshold Faces Pressure Before 2030

The speedup carries direct consequences for international climate policy. The Paris Agreement targets a long-term limit of restricting global warming to 1.5°C above preindustrial levels. While scientists emphasize that a single hot year does not permanently breach that threshold, the sustained velocity of the past decade threatens the timeline.

“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, PIK researcher and lead author of the study, via world-today-journal.com

While the study was designed to measure statistical acceleration rather than assign blame, the authors point to ongoing carbon dioxide emissions from fossil fuels as the primary driver. Another possibility raised by researchers is that cooling aerosols, which historically masked a portion of global heating by reflecting sunlight, may have diminished in their offsetting capacity.

Computer climate simulations show that periods of accelerated warming fit within the range of expected physical behavior. Ultimately, how quickly the planet continues to warm depends on how rapidly global emissions are driven down to zero.