Thirteen of world's hottest years on record have been in last 15 years
Thirteen of the world's hottest years on record have all occurred in the past 15 years and Arctic ice levels were this year the thinnest they have ever been, scientists have warned.
This year was also the hottest ever to coincide with the normally cooling effect of the La Nina weather system in the Pacific which tends to cause lower temperatures across the globe, the World Meteorological Organisation (WMO) found.
Without urgent action by all governments, they say, global temperatures could "very rapidly" reach the 2C mark which would trigger irreversible changes in the climate.
Environmental groups say such an outcome would have "devastating results" for people in poorer countries whose lives and livelihoods would be gravely affected.
The latest statistics were released in Durban, South Africa at the United Nation's 17th annual Conference of the Parties.
The WMO said the warmest 13 years of average global temperatures have all occurred in the 15 years since 1997, generating extreme weather that increased the intensity of droughts and heavy precipitation across the world.
In northern Russia, temperatures in the first 10 months of this year reached as much as 9C above normal.
In the Arctic, seen as a barometer for how the world will be affected in the future, last summer saw the complete disappearance of ice around the northeastern and northwestern corridors.
According to the Met Office, which helped to compile the WMO report together with the University of East Anglia, Arctic ice could disappear altogether by 2050.
"Our science is solid and it proves unequivocally that the world is warming and that this warming is due to human activities," Jerry Lengoasa, WMO Deputy Secretary-General, said.
"Climate change is real, and we are already observing its manifestations in weather and climate patterns around the world.
On Day Two of the climate change summit, delegations in Durban knuckled down to negotiating their positions on legally-binding carbon emissions targets, something the European Union is pushing for but China and the US remain resistant to.
Climate negotiators have set a goal of keeping temperatures from rising more than 2C above pre-industrial levels - they are already are 0.8C above the 1850 average.
Small island states such as the Maldives, which will be among the first to be submerged by rising sea levels caused by global warming, want the target reset to a rise of no more than 1.5 C.
Dave Britton, from the Met Office, said that while temperatures still varied from year to year, the long-term picture proved without question that temperatures were rising.
"There's no need for scientists to set specific dates to show the trend," he said. "If you go back to 1850, it speaks for itself. It's a very clear signal of global warming."
Meanwhile the UN announced next year's conference will be held in Qatar.
The choice of venue raised eyebrows among negotiators as the nation is a major gas exporter.