Global warming has accelerated, with Earth heating up at about 0.36°C per decade since 2014, twice the rate of 0.18°C per decade before then. Researchers attribute this speedup to human activities, raising concerns about reaching the Paris Agreement's 1.5°C limit sooner than expected. The findings come from an analysis of multiple temperature datasets.
An analysis by Stefan Rahmstorf at the University of Potsdam, Germany, and his colleagues examined five global temperature datasets and found a statistically significant acceleration in warming. Prior to 2013-14, the planet warmed at roughly 0.18°C per decade. Since then, the rate has risen to about 0.36°C per decade, confirmed with 98 percent confidence as due to climate change rather than natural fluctuations like El Niño.
This speedup has fueled debates among climate scientists, particularly after record-hot years in 2023 and 2024. Natural factors, such as El Niño events, volcanic eruptions, and solar cycles, were accounted for in the study by fitting curves to the temperature data. However, Zeke Hausfather at Berkeley Earth noted that some effects of these factors might not be fully removed, potentially leading to a slight overestimate of the acceleration. Still, he described the evidence as strong for a quickened warming rate.
If the current pace persists, global temperatures could exceed the 1.5°C threshold above preindustrial levels by 2028, according to the projections. One dataset from the European Centre for Medium-Range Weather Forecasts suggests this mark might already be reached this year based on a 20-year average. Rahmstorf emphasized the implications: “Every tenth of a degree matters and makes the impact of global warming worse in terms of extreme weather events, in terms of ecosystem impacts, also the risk of crossing tipping points.”
Scientists link the acceleration primarily to a 2020 reduction in sulphur dioxide emissions from shipping, which had previously formed cooling aerosols. Further reductions in air pollution from fossil fuels may continue this trend, though Rahmstorf suggested the warming rate could ease in the coming decade. Breaching 1.5°C heightens risks to warm-water coral reefs, the Greenland ice sheet, west Antarctica, and the Amazon rainforest.
The study appears in Geophysical Research Letters (DOI: 10.1029/2025GL118804).