Last month was the second-warmest September ever registered globally in an exceptional year "almost certain" to become the hottest on record, the EU climate monitor Copernicus said on Tuesday.

September saw extreme rainfall and destructive storms across the world, events that are occurring with greater severity and frequency as temperatures rise due to climate change.

The average global temperature last month was second only to September 2023, said Copernicus, which uses billions of measurements from satellites, ships, aircraft and weather stations to aid its calculations.

Last year was the hottest on record, but 2024 looks set to beat that.

Global warming is not just about rising temperatures, but the knock-on effect of all the extra heat trapped in the atmosphere and seas.

Warmer air can hold more water vapour, and warmer oceans mean greater evaporation, affecting rainfall and resulting in more intense downpours and storms.

In September some parts of the world saw "months' worth of rain falling in just a few days", said Samantha Burgess, deputy director of the Copernicus Climate Change Service.

"The extreme rainfall events of this month, something we are observing more and more often, have been made worse by a warmer atmosphere," Burgess said.

"The risk of extreme rainfall will continue to increase with rising temperatures." (AFP)