It is now "virtually certain" that 2024 - a year punctuated by intense heatwaves and deadly storms - will be the world's warmest on record, according to projections by the European climate service.
Global average temperatures across the year are on track to end up more than 1.5C above pre-industrial levels, which would make 2024 the first calendar year to breach this symbolic mark.
These high temperatures are mainly down to human-caused climate change, with smaller contributions from natural factors such as the El Niño weather pattern.
Scientists say this should act as an alarm call ahead of next week's UN climate conference in Azerbaijan, COP29.
"This latest record sends another stark warning to governments at COP29 of the urgent need for action to limit any further warming," says Liz Bentley, chief executive of the Royal Meteorological Society.
Global temperatures have been so high through the first 10 months of 2024 that only an implausibly sharp drop in the final two months would prevent a new record from being set.
In fact, it is likely that 2024 will end up at least 1.55C hotter than pre-industrial times, according to data from the European Copernicus Climate Change Service.
"Pre-industrial" refers to the benchmark period of 1850-1900, which roughly equates to the time before humans started significantly heating up the planet, for example by burning large amounts of fossil fuels.
The projection means that 2024 could surpass the current record of 1.48C, which was set only last year.
"This marks a new milestone in global temperature records," says Samantha Burgess, deputy director of Copernicus.
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