2020 saw hottest September on record as Arctic sea ice retreats to second lowest amount ever

Temperatures were unusually high last month in Siberia, the Middle East and regions of South America and Australia

September 2020 was the warmest September on record, according to the European Commission's flagship climate change program.

Last month was  0.05C (0.09F) warmer globally than September 2019, and 0.08C (0.14F) warmer than September 2016, previously the warmest and second-warmest for the month.

Temperatures were unusually high in a number of regions including in northern Siberia, the Middle East and parts of South America and Australia.

 Arctic sea ice also shrank to its second-lowest extent since satellite records began, according to scientists with the Copernicus Climate Change Service (C3S).

Across Europe, September average temperatures were around 0.2C  (0.36F) warmer than the previous warmest September in 2018. 

The research team also revealed that 2020 looks set to match, or even surpass, 2016, which is the warmest calendar year ever.

Last month, the National Oceanic and Atmospheric Administration (NOAA) announced the arrival of a La Niña event, which alters atmospheric circulation over the Pacific Ocean, and will impact whether this year ends up being the warmest on record.

La Niña can lead to more rain than average through Indonesia, cooler and wetter weather in southern Africa, and drier weather in southeastern China, NOAA reported. The monthly Copernicus report found cooler temperatures in the eastern equatorial Pacific, consistent with the La Niña.

The Siberian Arctic has been experiencing hotter than average temperatures over the past six months. While the region is known for big swings in temperature year on year, the heat has been "unusual in its magnitude and persistence", C3S noted.

Arctic sea ice extent last month has also declined to the second lowest amount ever recorded, following September 2012. 

Sea ice extent in the polar region has been dramatically declining since the first satellite observations in the late Seventies. The trend is visible all year round but it most marked in September, when ice cover is at its annual minimum.

Carlo Buontempo, Director of Copernicus Climate Change Service, said: “In 2020, there was an unusually rapid decline in Arctic sea ice extent during June and July, in the same region where above average temperatures were recorded, preconditioning the sea ice minimum to be particularly low this year. "The combination of record temperatures and low Arctic sea ice in 2020 highlight the importance of improved and more comprehensive monitoring in a region warming faster than anywhere else in the world.”

This article has been updated to reflect the correct temperature increases