Last year matched 2016 as the world’s hottest on record, rounding off the hottest decade on record as the devastating effects of climate change intensified, the EU’s Copernicus Climate Change Service said on Friday.
Europe experienced its hottest year on record in 2020 after an exceptionally warm winter and autumn.
The Arctic also suffered extreme heat and atmospheric concentrations of planet-warming carbon dioxide continued to rise.
Worryingly, 2020 matched the 2016 record despite the effects of a cooling La Nina weather pattern, whereas 2016 began with a strong warming El Nino event.
Scientists said the latest data underscored the need for countries and corporations to slash greenhouse gas emissions quickly enough to reach the goals of the 2015 Paris Agreement to avoid catastrophic climate change.
"The extraordinary climate events of 2020 and the data from the Copernicus Climate Change Service show us that we have no time to lose," Matthias Petschke, director for space in the European Commission, said.
In 2020, temperatures globally were an average of 1.25°C higher than in pre-industrial times, Copernicus said, and the last six years were the world's hottest on record.
The Paris accord aims to cap the rise in temperatures to "well below" 2°C and as close as possible to 1.5°C to avoid the most devastating impacts of climate change.
Last year also saw the highest temperature ever reliably recorded, when in August a California heatwave pushed the temperature at Death Valley in the Mojave Desert up to 54.4°C.
The Arctic and northern Siberia continued to warm more quickly than the planet as a whole in 2020, with temperatures in parts of these regions averaging more than 6°C above the 30-year average baseline, Copernicus said.
The region also had an "unusually active" wildfire season, with fires poleward of the Arctic Circle releasing a record 244 million tonnes of CO2 in 2020, over a third more than in 2019.
Arctic sea ice continued to deplete, with July and October both setting records for the lowest sea ice extent in that month.
Scientists who were not involved in the study said it was consistent with growing evidence that climate change is contributing to more intense hurricanes, fires, floods and other disasters.
Unprecedented levels in CO2 emissions were reached despite a 7 per cent drop in emissions due to pandemic lockdowns.
Stefan Rahmstorf, head of Earth system analysis at the Potsdam Institute for Climate Impact Research, said the world urgently needed to stabilise the climate.
"Since CO2 accumulates in the atmosphere like water in a bathtub, if we turn down the tap by seven percent, the CO2 level just rises a bit more slowly," he said.
"We need to shut off the tap to get a stable climate again."
