Last month was the world’s warmest January on record. This has raised questions about the pace of climate change. January 2025 broke the previous record set in January 2024 by nearly 0.1°C.
We've released the Berkeley Earth temperature update for January 2025.
It was the warmest January on record at 1.64C above preindustrial levels, and 0.09°C above the prior record set in 2024. pic.twitter.com/v3XWu9vixx
— Zeke Hausfather (@hausfath) February 11, 2025
This was a surprise to scientists. They had expected January to be slightly cooler due to a shift in weather patterns in the Pacific Ocean. The world is warming mainly because of greenhouse gas emissions from human activities like burning fossil fuels.
Last week, @CopernicusEU released its January climate report, highlighting the climate trends of the month 🌡️
📈 Global: 1.75°C above pre-industrial levels
🌍 Europe: 2.51°C above the 1991-2020 average👉 https://t.co/3syqzfEFbw pic.twitter.com/08ZHDAE1Hf
— EU Climate Action (@EUClimateAction) February 11, 2025
However, scientists say they cannot fully explain why last month was so hot. “The specifics of exactly why 2023, 2024, and the start of 2025 were so warm — other elements are involved there. We’re trying to pin those down,” said Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies.
January 2025 marked the second consecutive month of record-low Arctic sea ice for the time of the year, 6% below the 1991–2020 average.📉
Since June 2024, the Arctic sea ice extent has stayed well below average.
Full details in the #C3S January CB: https://t.co/X6RvFrEMrJ pic.twitter.com/4rCoknMbtW— Copernicus ECMWF (@CopernicusECMWF) February 12, 2025
January 2025 was 1.75°C warmer than in the late 19th century before humans started significantly warming the climate. Last year, global temperatures were boosted by El Niño, a natural weather pattern that usually leads to warmer temperatures. This year, La Niña conditions are developing instead.
January 2025 was the 18th month in a 19-month period in which the global-average temperature was more than 1.5°C above pre-industrial level. 🧵 pic.twitter.com/srpzwlK9FJ
— Copernicus ECMWF (@CopernicusECMWF) February 11, 2025
Record-breaking heat raises questions
La Niña typically has a cooling effect. “If you’d asked me a few months ago what January 2025 would look like relative to January 2024, my best shot would have been it would be cooler,” said Adam Scaife, head of monthly to decadal predictions at the UK Met Office.
“We now know it isn’t, and we don’t really know why that is.”
Several theories have been proposed to explain the recent warmer-than-expected temperatures. One idea is that the oceans are having a prolonged response to the 2023-24 El Niño. Another theory points to a reduction in small particles called aerosols in the atmosphere.
These particles usually help offset some warming by reflecting sunlight. The months ahead should provide more insight into whether the extra warmth is temporary or marks an acceleration in climate change. Most researchers still expect 2025 will end up slightly cooler than 2023 and 2024.
However, the recent record warmth means they can’t be certain. “In time, 2025 is likely to be one of the cooler years that we experience,” said Dr. Samantha Burgess, deputy director of the Copernicus climate service.
Unless we turn off that tap to greenhouse gas emissions, then global temperatures will continue to rise.
Cameron is a highly regarded contributor in the rapidly evolving fields of artificial intelligence (AI) and machine learning. His articles delve into the theoretical underpinnings of AI, the practical applications of machine learning across industries, ethical considerations of autonomous systems, and the societal impacts of these disruptive technologies.
