It is “virtually certain” that 2024 will be the hottest year on record, the European Union’s space programme has found.

The prognosis comes the week before diplomats meet at the Cop29 climate summit and a day after a majority of voters in the US, the biggest historical polluter of planet-heating gas, chose to make Donald Trump president.

Trump has described climate change as a “hoax” and promised to roll back policies to clean up the economy.

The report found 2024 is likely to be the first year more than 1.5C (2.7F) hotter than before the Industrial Revolution, a level of warming that has alarmed scientists.

“This marks a new milestone in global temperature records and should serve as a catalyst to raise ambition for the upcoming climate change conference,” said Dr Samantha Burgess, deputy director of the Copernicus Climate Change Service.

The scientists found global temperatures for the past 12 months were 1.62C greater than the 1850-1900 average, when humanity started to burn vast volumes of coal, oil and gas.

In their monthly climate bulletin, they said October 2024 was the second-warmest October on record, behind only October 2023, with temperatures 1.65C greater than preindustrial levels. It was the 15th month in the past 16 to be higher than the 1.5C mark.

World leaders promised to stop the planet from heating 1.5C by the end of the century but are on track to heat it by roughly double that.

Scientists say a single year above the threshold does not mean they have missed the target, as temperature rise is measured over decades rather than years, but warn that it will force more people and ecosystems to the brink of survival.

“Our civilisation never had to cope with a climate as warm as the current one,” said Carlo Buontempo, the director of Copernicus. “This inevitably pushes our ability to respond to extreme events – and adapt to a warmer world – to the absolute limit.”

The Copernicus findings are based on billions of weather measurements from satellites, ships, aircraft and weather stations. The temperature analyses in the ERA5 dataset on which the bulletin relies differ slightly from other prominent datasets used by climate scientists in the US and Japan.

The scientists also found that Arctic sea ice had reached its fourth-lowest monthly level for October, at 19% below average, while Antarctic sea ice extent hit its second-lowest for October, at 8% below average.

They pointed to heavier-than-normal rains that hit large parts of Europe, including Spain, where flash floods killed more than 200 people as they ripped through villages and swamped homes with mud.

Last week, the World Meteorological Organization (WMO) found the concentration of planet-heating pollutants clogging the atmosphere had hit record levels in 2023. It found carbon dioxide was accumulating faster than at any time in human history, with concentrations having risen by more than 10% in just two decades, heating the planet and making extreme weather more violent.

“The most effective solution to address the climate challenges is a global commitment on emissions,” said Buontempo.