The world witnessed yet another record-breaking warm month in January 2025, defying expectations of a cooler year due to a developing La Niña and a frigid winter in the United States, according to data from the European climate service Copernicus.
Unprecedented January Heat
Copernicus reported that January 2025 was 0.09°C hotter than January 2024, the previous warmest January on record, and 1.75°C above pre-industrial levels. This marks the 18th month out of the last 19 that global temperatures have touched or exceeded the 1.5°C warming limit set by international climate agreements.
Despite La Niña’s typical cooling influence, global temperatures have not dropped as expected, raising concerns among climate scientists.
Scientists Warn of Accelerating Global Warming
A new study by James Hansen, a former NASA climate scientist, suggests that global warming is accelerating, a claim that has sparked debate in the scientific community. Hansen’s research indicates that the planet has warmed at nearly double the rate in the last 15 years compared to the previous 40.
“I’m confident this higher rate will continue for at least several years,” Hansen stated, adding that 2025 could still compete with 2024 as the hottest year on record.
Samantha Burgess, a climate strategist at Copernicus, pointed to record-high ocean temperatures as a key driver of January’s unexpected warmth. Even as the equatorial Pacific cooled due to La Niña, other oceanic regions remained abnormally warm, pushing global temperatures higher.
The Arctic saw alarming temperature spikes, with parts of the Canadian Arctic experiencing temperatures 30°C above average, leading to sea ice melt in January. Copernicus reported that Arctic sea ice levels tied the record for lowest January extent, while the U.S. National Snow and Ice Data Center ranked it as the second-lowest on record.
What Lies Ahead?
While February has started slightly cooler, scientists caution that 2025 remains in the race for another record-hot year. The unexpected resilience of warming trends, despite natural cooling cycles, underscores the overwhelming influence of greenhouse gas emissions from fossil fuels.
With Hansen’s warning that the planet is warming faster than previously thought, the latest findings add urgency to global climate action efforts.