Megafires are raging in the Arctic ITAR-TASS News Agency/Alamy Live News

The Arctic is on fire. Dozens of wildfires of an unprecedented intensity have been burning across the Arctic circle for the past few weeks, releasing as much CO2 in just one month as Sweden’s total annual emissions.

Fires in the region are not unknown but the scale of the blazes, predominantly in boreal peatlands across Siberia, is surprising. Satellite measurements show the amount of energy released by the fires in June is more than that released by all the previous nine years of the month combined.

“It’s quite striking, it does really stand out,” says Mark Parrington at European Centre for Medium-Range Weather Forecasts. The last time the region had such intense fires was 15 years ago.


The driver for the fires appears to be the unusually high temperatures that affected many parts of the world in June, with the month marking the hottest June on record in Europe. The Arctic was also warmer than average. “It’s hotter and drier. If the temperature is high enough and there’s ignition, fuel burns,” says Parrington.

The exact size of the area on fire is not entirely clear. But Thomas Smith of the London School of Economics says his analysis of satellite photos suggest some of the fires appear to be bigger than 100,000 hectares, which would classify them as megafires. There are signs they are still burning, though detection is currently hampered by cloud cover. “Some hotspots are apparent through gaps in clouds which suggest fires are continuing,” he says.

The fires appear to be mostly on carbon-rich peatland. Parrington calculates the wildfires in June released around 50 megatonnes of CO2, on par with Sweden’s total emissions in 2017. That CO2 will bring about more warming, in a positive feedback loop.

The blazes appear to also be accelerating climate change by depositing soot and ash on sea ice. Satellite photos in June show sea ice in the Laptev Sea and East Siberian Sea turning darker, which will exacerbate melting, in turn bringing about more warming because the sea is darker than ice and so absorbs more of the sun’s energy. Arctic sea ice extent loss “ramped up” in June and was the second lowest for the month on record, data released on Tuesday shows.

These sort of Arctic wildfires are in line with predictions made a decade ago, when researchers said they expected the region – which is warming faster than the rest of the world – to see some of the biggest increases in fires. “What we might be seeing this year is widespread breach of a critical temperature threshold, leading to such widespread fires,” says Smith. Guillermo Rein of Imperial College London says: “The term ‘Arctic fire’ is a relatively new arrival to science and still causes consternation. It is not part of common sense yet.”

What started the current round of fires is not known, but given how sparsely inhabited the region is, lightning is believed to be the main cause of ignition.