2025 to be second or third-hottest year on record: EU scientists

This year is set to be the world’s second or third-warmest on record, potentially surpassed only by 2024’s record-breaking heat, the European Union’s Copernicus Climate Change Service (C3S) said on December 9.

The data is the latest from C3S following last month’s COP30 climate summit, where governments failed to agree to substantial new measures to reduce greenhouse gas emissions, reflecting strained geopolitics as the U.S. rolls back its efforts, and some countries seek to weaken CO2-cutting measures.

This year will also likely round out the first three-year period in which the average global temperature exceeded 1.5ºC above the 1850-1900 pre-industrial period, when humans began burning fossil fuels on an industrial scale, C3S said in a monthly bulletin.

“These milestones are not abstract – they reflect the accelerating pace of climate change,” said Samantha Burgess, strategic lead for climate at C3S.

Extreme weather continued to hit regions around the globe this year. Typhoon Kalmaegi killed more than 200 people in the Philippines last month. Spain suffered its worst wildfires for three decades because of weather conditions that scientists confirmed were made more likely by climate change.

Last year was the planet’s hottest on record.

While natural weather patterns mean temperatures fluctuate year to year, scientists have documented a clear warming trend in global temperatures over time, and confirmed that the main cause of this warming is greenhouse gas emissions from burning fossil fuels.

The last 10 years have been the 10 warmest years since records began, the World Meteorological Organisation said earlier this year.

The global threshold of 1.5 Celsius is the limit of warming which countries vowed under the 2015 Paris climate agreement to try to prevent, to avoid the worst consequences of warming.

The world has not yet technically breached that target – which refers to an average global temperature of 1.5 Celsius over decades. But the U.N. said this year that the 1.5 Celsius goal can no longer realistically be met and urged governments to cut CO2 emissions faster, to limit overshooting the target.

C3S’s records go back to 1940, and are cross-checked with global temperature records going back to 1850.

In a separate update ahead of COP30, the World Meteorological Organisation said the period from 2015 to 2025 is also set to rank as the 11 warmest years on instrumental record, with 2023-2025 the three warmest years and 2025 about 1.4ºC above the pre-industrial average so far.

Likewise the UN Environment Programme’s Emissions Gap Report 2025 had warned that even if countries implement their national climate plans in full, global temperatures this century would still be headed for around 2.3-2.5ºC of warming while current policies would deliver around 2.8ºC.

It also estimated that global emissions would have to drop by half by 2035 to keep the 1.5ºC pathway open, at least briefly.

Analysts have also noted an unprecedented 0.4ºC rise in global temperature in just two years, suggesting the world may already be edging into the psychologically important post-1.5ºC regime

With inputs from agencies.