One of the datasets analysed in the study, from the European Union’s Copernicus climate service, suggests that the world could cross the 1.5°C long-term warming threshold as early as this year if current warming continues.
The other four datasets indicate that the threshold could be crossed between 2028 and 2029.
Crossing this level would mark a major milestone in climate change. Governments agreed under the Paris climate agreement to try to keep global warming below 1.5°C to avoid the worst impacts.
Claudie Beaulieu, a climate scientist at the University of California Santa Cruz, said the findings show the window to limit warming to 2°C may also be shrinking.
If the faster warming continues, she said, the chances of staying below this level will become much smaller.
Acceleration may still be temporary
Despite the worrying results, scientists say it is still possible that the recent rise in warming speed could be temporary.
Beaulieu explained that similar patterns have appeared before. For example, the strong El Niño event in 1998 created a period when temperatures suddenly jumped.
In the years after that, warming appeared to slow down, which some people wrongly interpreted as a pause in climate change.
Because of this, scientists say it will be important to continue observing global temperatures over the next several years.
This will help determine whether the current acceleration represents a long-term shift or simply a short-term variation.