February 6, 2025

expert reaction to Copernicus data reporting that January 2025 was the warmest on record globally

Scientists comment on data published by Copernicus that shows January 2025 was the warmest on record globally.

Dr Joel Hirschi, Associate Head of Marine Systems Modelling, UK’s National Oceanography Centre (NOC), said:

“One should not infer too much out of one month temperature data, as temperature anomalies can vary a lot.  The global temperatures for 2024 and now early 2025 have been tracking the record temperatures we saw in 2023 (and 2024) quite closely.  The last few months of 2024 were slightly cooler than in 2023 and January 2025 is now just warmer than January 2024.

“Despite La Niña conditions having developed in the tropical Pacific, global temperatures remain very high.  This pattern is similar to what we observed after the El Niño events of 2015/16 and 2019/20 when global temperatures remained close to record warm levels even after the onset of La Niña conditions.

“Global sea surface temperatures are a bit lower than in 2024 and will likely remain lower as we move further into 2025.”

Prof Richard Allan, Professor of Climate Science, University of Reading, said:

“Human caused warming of the ocean is accelerating and this is dominating to an ever greater extent over the natural year to year fluctuations in climate.  Although the swing from moderate El Niño to a weak La Niña during 2024 had a small cooling effect on the surface of the ocean, heat continues to flood into the climate system as atmospheric greenhouse gases continue to rise and the reflective haze of aerosol particle pollution diminishes in some regions following clean air regulation.  Aside from a cooler than average equatorial band in the eastern Pacific due to the weak La Niña conditions, much of the rest of the global sea surface remains remarkably warm in early 2025, primarily a result of human-caused warming of climate.

“Changing weather patterns from week to week can rapidly alter temperatures over continental regions, which warm up and cool down more quickly than the oceans.  Based upon the most up to date, state of the art Copernicus data, large areas of Europe, Canada and Siberia experienced less cold weather than is normal for January but parts of South America, Africa, Australia and Antarctica also experienced above average temperatures which contributed along with the balmy oceans to the unexpected record global temperatures at the beginning of 2025.  As industrial activity continues to spew greenhouse gases into the air, this growing heating effect is tipping the balance toward record warmth and worsening hot, dry and wet extremes.”

Prof Bill McGuire, Emeritus Professor of Geophysical & Climate Hazards, UCL, said:

“The fact that the latest robust Copernicus data reveals the January just gone was the hottest on record – despite an emerging La Nina, which typically has a cooling effect – is both astonishing and, frankly terrifying.  Having crashed through the 1.5C limit in 2024, the climate is showing no signs of wanting to dip under it again, reflected by the fact that this is the 18th of the last 19 months to see the global temperature rise since pre-industrial times top 1.5C.  On the basis of the Valencia floods and apocalyptic LA wildfires, I don’t think there can be any doubt that dangerous, all-pervasive, climate breakdown has arrived.  Yet emissions continue to rise, while fossil fuel corporations seek to expand operations. Grim doesn’t even begin to describe our prospects.”

Dr Friederike Otto, Senior Lecturer at the Centre for Environmental Policy and co-lead of World Weather Attribution, Imperial College London, said: 

“This January is the hottest on record because countries are still burning huge amounts of oil, gas and coal.

“Sure, El Niño and La Niña add or take off a tiny bit of warming, but the reason we’ve broken another record is the continued burning of fossil fuels.

“The LA wildfires were a stark reminder that we have already reached an incredibly dangerous level of warming.  We’ll see many more unprecedented extreme weather events in 2025.

“If politicians really care about people’s lives and their children’s futures, transitioning away from fossil fuels would need to be top of their agenda, to make the world safer and fairer.

“This data shows very clearly what hundreds of other high-quality analyses have shown in recent decades – more burning of fossil fuels leads to more emissions that lead to more warming.”

Declared interests

Dr Joel Hirschi: “No conflicts of interest.”

Prof Richard Allan: “No conflicting interests.”

Dr Friederike Otto: “No DOIs.”