According to scientists, January 2025 was the hottest January on record globally, adding new concerns about the rate of climate change. Contrary to expectations that the month would be cooler away from the El Niño weather pattern, January 2025 outpaced the previous year’s record by nearly 0.1°C, reported the European Copernicus Climate Service.
The sharp increase in temperatures is blamed on human-made greenhouse gas emissions, mainly due to the combustion of fossil fuels. But for the reasons behind the record-breaking heat last month, scientists are still trying to piece together. This extends a trend of unexpectedly high temperatures seen since the middle of 2023, placing the global average currently about 0.2°C above forecast.
As the director of NASA’s Goddard Institute for Space Studies Gavin Schmidt explained, the warming trend is essentially because of the rising concentration of greenhouse gases in the atmosphere. But why things have been so warm in recent months is still being researched.
It sets a dangerous precedent that January 2025 has recorded an average global temperature 1.75°C above the levels experienced back in the late 19th century. Going back to earlier in 2024, El Niño conditions-a phase characterized by warmer surface waters in the eastern tropical Pacific-typically raises global temperatures. This year, La Niña conditions have emerged, associated with cooler temperatures.
Scientists predicted a cooler January 2025, but temperatures begged to differ. As described by Adam Scaife of the UK Met Office: “We now know it isn’t, and we don’t really know why that is.”
Various theories have surfaced regarding the unanticipated warmth of the past two years. One theory suggests a prolonged ocean response to the previous El Niño, which, despite its moderate strength, may have released accumulated ocean heat into the atmosphere. However, as time passes, this explanation may become less plausible.
Another critical factor could be a reduction of aerosols in the atmosphere. Historically, these particles have contributed to masking part of the warming effect by reflecting sunlight. Current efforts to reduce aerosols from shipping and industry in general reduce their cooling impact, which can accelerate warming.
While some scientists remain skeptical about the significance of aerosol reduction, if proved valid, this could imply more serious climate impacts than previously estimated. Concerns also extend to possible feedback mechanisms where warming oceans might lead to fewer reflective clouds, further amplifying temperature increases.
In the light of these developments, which researchers continue to monitor, a consensus exists that 2025 might finally be cooler than the record, exceptionally warm years of 2023 and 2024. The sustained high temperatures imply, however, that record-breaking years will be more frequent, unless determinate action is taken to reduce greenhouse gas emissions. “Unless we turn off that tap to [greenhouse gas] emissions, then global temperatures will continue to rise,” said Dr. Samantha Burgess from Copernicus.
