January 2025 Was The Hottest On Record, Even With A Weaker La Niña

Data from the Copernicus Climate Bulletin shows that January 2025 was 1.75 °C (3.15 °F) above the pre-industrial level, and above the 1.5°C (2.7 °F) threshold established in the Paris Agreement to try to avoid disastrous outcomes from the unfolding climate crisis. 

The threshold has not been crossed for good, as there are monthly and annual variations. That said, the situation is of great concern, as last month was the 18th in the last nineteen months during which the global average surface air temperature was higher than 1.5°C above the pre-industrial level.  

“This January is the hottest on record because countries are still burning huge amounts of oil, gas and coal,” Dr Friederike Otto, Senior Lecturer at the Centre for Environmental Policy and co-lead of World Weather Attribution, Imperial College London, said in a statement to the Science Media Centre. “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.”

In the Northern Hemisphere, where winter is supposed to be in full swing, there have been more mild days than is typical. Large areas of Europe, Canada, and Siberia were hotter than usual, and most of Europe was also wetter than usual. Equally, large areas of South America, Africa, Australia, and Antarctica, have experienced warmer than usual conditions.

The extensions of both Arctic and Antarctic ice were also low, with the former getting to the lowest point in January since 2018.

Over the last few months of 2024, there was a swing from moderate El Niño to a weak La Niña. This had a cooling effect on the surface of the ocean, but not enough to offset the heat of the greenhouse gases in the atmosphere yet.

“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 1.5 °C 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 1.5 °C,” Prof Bill McGuire, Emeritus Professor of Geophysical & Climate Hazards, University College London, said in a statement to the Science Media Centre.

“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.”

Lives and livelihoods lost from the increase in the incidence and/or severity of natural disasters are expected to continue in the face of climate inaction. The Trump administration is taking the US out of the Paris Agreement, and staffers with Elon Musk’s Department of Government Efficiency were reportedly seen entering the National Oceanic and Atmospheric Administration to censor climate data.  

“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,” Dr Otto concluded.