Global warming is accelerating since 2015, new study finds; 1.5°C limit could be breached before 2030

A new study has found that global warming has been speeding up since around 2015, with researchers reporting the first statistically significant evidence that Earth’s long-term warming rate is accelerating after filtering out the effects of natural climate variability.

Published in the journal Geophysical Research Letters, the analysis by the Potsdam Institute for Climate Impact Research (PIK) found that global temperatures have risen by about 0.35°C per decade over the past 10 years—almost double the average warming rate of just under 0.2°C per decade recorded between 1970 and 2015.

Scientists isolate the long-term warming trend

To uncover the underlying climate signal, researchers removed the influence of short-term factors such as El Niño, volcanic eruptions and changes in solar activity, which can temporarily boost or suppress global temperatures.

The team analysed five major global temperature datasets—compiled by NASA, NOAA, HadCRUT, Berkeley Earth and ERA5—and found consistent evidence of accelerated warming across all of them.

According to lead author Stefan Rahmstorf, the adjusted data show more than 98% statistical certainty that global warming has accelerated since around 2015, making it highly unlikely that the observed trend is due to chance.

Two methods, one conclusion

Researchers used two independent statistical techniques to test whether the warming rate had changed over time.

One method examined whether the temperature curve has become steeper rather than rising at a constant pace, while the other identified shifts in warming rates across different periods. Both approaches pointed to the same conclusion: Earth’s warming has accelerated in the past decade.

Although the extreme heat of 2023 and 2024 became slightly less pronounced after adjusting for El Niño and the solar maximum, both years still remained the warmest on record.

What does it mean?

The study did not investigate the exact cause of the acceleration but noted that climate models have long suggested periods in which warming can speed up. Scientists say the findings are consistent with the effects of continued greenhouse gas emissions.

If the current pace continues, researchers warn that the world could permanently exceed the Paris Agreement’s 1.5°C warming target before 2030.

The 1.5°C threshold refers to long-term average global temperatures above pre-industrial levels. Scientists stress that crossing the limit in a single year does not mean the goal has been permanently breached; sustained warming over many years is what matters.

The researchers concluded that future warming will largely depend on how quickly global carbon dioxide emissions from fossil fuels are reduced, with faster emissions cuts remaining the most effective way to slow climate change.