This year is "virtually certain" to eclipse 2023 as the world's warmest since records began, the European Union's Copernicus Climate Change Service (C3S) says.
The data was released on Thurdsay, ahead of next week's UN COP29 climate summit in Azerbaijan, where nations will try to agree a huge increase in funding to tackle climate change.
Donald Trump's victory in the US presidential election has dampened expectations for the talks.
C3S said from January to October, the average global temperature had been so high that 2024 was sure to be the world's hottest year - unless the temperature anomaly in the rest of the year plunged to near-zero.
"The fundamental, underpinning cause of this year's record is climate change," C3S Director Carlo Buontempo told Reuters.
"The climate is warming, generally. It's warming in all continents, in all ocean basins. So we are bound to see those records being broken," he said.
The scientists said 2024 would also be the first year in which the planet is more than 1.5C hotter than in the 1850-1900 pre-industrial period, when humans began burning fossil fuels on an industrial scale.
Carbon dioxide emissions from burning coal, oil and gas are the main cause of global warming.
Sonia Seneviratne, a climate scientist at public research university ETH Zurich, said she was not surprised by the milestone, and urged governments at COP29 to agree stronger action to wean their economies off CO2-emitting fossil fuels.
"The limits that were set in the Paris agreement are starting to crumble given the too-slow pace of climate action across the world," Seneviratne said.
Countries agreed in the 2015 Paris Agreement to try to prevent global warming surpassing 1.5C (2.7 degrees Fahrenheit), to avoid its worst consequences.
The world has not breached that target - which refers to an average global temperature of 1.5C over decades - but C3S now expects the world to exceed the Paris goal around 2030.
"It's basically around the corner now," Buontempo said.
Every fraction of temperature increase fuels extreme weather.
In October, catastrophic flash floods killed hundreds of people in Spain, record wildfires tore through Peru, and flooding in Bangladesh destroyed more than one million tons of rice, sending food prices skyrocketing.
In the US, Hurricane Milton was also worsened by human-caused climate change.
C3S' records go back to 1940, which are cross-checked with global temperature records going back to 1850.
