
January 2025 was the warmest on record, continuing a series of extreme global temperatures despite a shift towards a cooling La Nina weather pattern, European Union scientists have sounded the alarm.
January continued a streak of exceptional heatwaves, in which 18 of the last 19 months saw an average global temperature of more than 1.5 degrees Celsius above pre-industrial times, the EU's Copernicus Climate Change Service said in a monthly bulletin.
This happened despite the world shifting from the warming El Nino pattern - which helped make 2024 the world's warmest year on record - and back towards its cooler La Nina phenomenon, which involves cooling equatorial Pacific waters and can curb global temperatures.
The average global temperature in January was 1.75C higher than in pre-industrial times.
Copernicus estimates that La Nina is not yet fully developed and the world is currently in neutral conditions between the two phases. Other data patterns may differ, with US scientists showing last month that La Nina conditions were forming.
Scientists at Berkeley Earth and the UK Met Office have said they expect 2025 to be the third warmest year on record - cooler than 2024 and 2023 due to the shift towards La Nina, although uncertainty remains about how the phenomenon will develop.
Globally, average sea surface temperatures in January were the second highest ever recorded for this month, surpassed only in January 2024.
A report by World Weather Attribution found that a "perfect storm" of climate change and cyclical La Niña weather patterns triggered catastrophic flooding across southern Africa over the past month, killing 200 people and affecting hundreds of thousands more.
The report showed that the intensity of such extreme rainfall events has increased by 40% since pre-industrial times - a clear sign that warmer ocean temperatures linked to greenhouse gas emissions are partly to blame - and that the current La Niña conditions had made things worse.
La Niña involves temporary cooling of temperatures in the central and eastern Pacific Ocean. The World Meteorological Organization has predicted a weak La Niña in this cycle, but warned that warmer-than-normal sea temperatures linked to climate change are increasing the likelihood of flooding and drought.
In China, the Meteorological Administration found that the average annual temperature hit a record for the second year running at 10.9 degrees Celsius (51.6 degrees Fahrenheit), with the hottest days ever recorded.