Climate Change Accelerates: 2025 Set to be Among Hottest Years

October 2025 was the third-warmest globally on record, with an average surface air temperature of 15.14 degrees Celsius, which is 0.70 degrees above the 1991 to 2020 average for the month, according to data from the European Union's Copernicus Climate Change Service.

The report states that 2025 is virtually certain to finish as either the second- or third-warmest year on record, potentially tied with 2023, which is currently the second-warmest year, and only behind 2024, the warmest year recorded.

This data reflects the accelerating pace of climate change, driven by the burning of fossil fuels that releases greenhouse gases, trapping heat in the atmosphere. In addition, the report highlights that global warming is reducing low-level cloud cover, which contributes further to rising temperatures.

October 2025 was just 0.16 degrees cooler than the warmest October on record, in 2023, and 0.11 degrees cooler than October 2024. The month was 1.55 degrees above the estimated 1850 to 1900 average, marking it as the first month above 1.5 degrees since April 2025.

While it's unlikely that 2025 will exceed the 1.5 degrees threshold above pre-industrial levels, the average global temperature for the three-year period from 2023 to 2025 is expected to exceed this limit.

According to Copernicus, this would represent the first three-year average to surpass 1.5 degrees since climate records began in the 18th century. Samantha Burgess, Strategic Lead for Climate at Copernicus, emphasizes that we are in a decade where the 1.5 degrees limit is likely to be exceeded, underscoring the urgent need for action.

In Europe, the average temperature was 10.19 degrees Celsius for October 2025, which is 0.60 degrees above the 1991 to 2020 average, although it did not rank among the ten warmest on record. The most significant above-average temperatures were reported over Fennoscandia and the southern Iberian Peninsula, with below-average temperatures in southeastern Europe.

Outside of Europe, the polar regions experienced the highest temperature anomalies, particularly in northeastern Canada, the central Arctic Ocean, and East Antarctica. Sea surface temperatures in October 2025 were also concerning, with an average of 20.54 degrees Celsius, marking the third-highest value on record for that month.

The North Pacific continued to see significant above-average sea surface temperatures, with record highs in the west, while the European Arctic Ocean experienced much-above to record-breaking sea surface temperatures.

In terms of sea ice, the Arctic saw an average extent 12 percent below average, ranking as the eighth lowest for October. The Antarctic region had its third-lowest extent for October, at six percent below average, particularly in the Bellingshausen Sea and the Indian Ocean sector, coinciding with much-above-average surface temperatures in East Antarctica.