This year is "effectively certain" to be the hottest on record and the first above a critical threshold to protect the planet from dangerously overheating, Europe's climate monitor said.

The new benchmark affirmed by the Copernicus Climate Change Service caps a year in which countries rich and poor were hammered by disasters that scientists have linked to humanity's role in Earth's rapid warming.

Copernicus said an unprecedented spell of extraordinary heat had pushed average global temperatures so high between January and November that this year was sure to eclipse 2023 as the hottest yet.

"At this point, it is effectively certain that 2024 is going to be the warmest year on record," the EU agency said in its monthly bulletin.

In another  milestone, 2024 will be the first calendar year more than 1.5C hotter than pre-industrial times before humanity started burning large volumes of fossil fuels.