“THE conditions we’ve seen in the Arctic this year have been truly remarkable, and not in a good way,” says Michael Meredith, a polar researcher at the British Antarctic Survey.
Even for a region that has warmed twice as fast as the rest of the planet, this year’s Arctic fires and ice melt have been extraordinary. The first half of 2020 has seen temperature records tumble in one of the coldest places on Earth.
The symbolic milestone of 100°F was passed in the , on the way to a record high of 38°. Longyearbyen in the Norwegian archipelago of Svalbard in the Arctic Ocean hit an all-time high of 21.7°C in July, hotter than Oslo that day. The Svalbard Global Seed Vault, where thousands of crop seeds are stored, was built in this location thanks to its supposedly cool climate.
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It hasn’t just been hot, but hot for an extended period. The Arctic circle was around 8°C above average for the first half of the year, and 10°C above average in June. Although this has been driven by a natural variation in the weather-affecting jet stream that travels high above the North Atlantic, it would also have been almost impossible without the greenhouse gases we have pumped into the atmosphere. Siberia’s heatwave is thought to have been made at least 600 times more likely by climate change. “I think 2020 is a clear window into what is to come,” says Meredith.
Unfrozen north
One big effect has been drastically shrinking sea ice, which polar bears rely on to hunt their prey. Meanwhile, satellite images have brought a daily reminder of fires blazing in northern forests and underground peat, resulting in the region releasing the most carbon dioxide in 18 years. And Russia’s worst oil spill in modern times, which began near Norilsk in the Arctic on 29 May, seems to have been due to a container collapsing as the permafrost it sat on thawed in the heat.
The simultaneous nature of these events has researchers worried. Last year saw record fires, while . This year is different. “It’s the confluence of all of them. Each of these as individual events and phenomena are exceptional in their own right,” says Carly Phillips at the University of British Columbia in Canada. “The fact they’re all occurring simultaneously should raise alarms.”
“38°
Record Arctic temperature, recorded this June”
“600
Climate change made the Siberian heatwave at least this many times more likely”
“18
Arctic CO2 emissions haven’t been as high for this many years”
Arctic sea ice, which melts in summer and usually reaches its minimum extent in September before beginning to refreeze, has been on a sharp decline for decades. The 14 smallest extents have occurred in the past 14 years, says Walt Meier at the US National Snow and Ice Data Center (NSIDC).
The melt started unusually early this year. As of 6 August, the ice covered 5.8 million square kilometres, 27 per cent less than the 1980-2010 average. At this rate, 2020 could break the 2012 record for the lowest area of ice ever seen.
Julienne Stroeve, also at the NSIDC, was in the Arctic from December 2019 to March 2020 aboard a ship deliberately stuck in an ice floe to study the region. “The thing that surprised me the most was how dynamic the ice pack was. It was very mobile,” she says. “That’s probably a result of thinner ice overall.”
That thinness is partly due to a weather phenomenon called the Arctic oscillation, which is strongly positive this year, causing sea ice to drift towards the North Pole. That motion away from the coast of Siberia leads to thinner ice forming. Siberia’s heat provides extra stress. Geographically, the ice loss has been uneven this year, with large areas of open water in the Laptev and Barents seas, but ice above north Alaska at average levels.
Fire alarm
On land, this year’s Arctic fires have already been more severe than those in 2019, spewing more carbon into the atmosphere in July alone than the 50 megatonnes released in the whole of 2019 – and last year was a record-breaker.
“In July, we saw a real step change,” says Mark Parrington at the European Centre for Medium-Range Weather Forecasts in the UK, who has been tracking the blazes by satellite since isolated ones broke out unusually early at the start of May. They have since merged into bigger conflagrations in the Russian republic of Sakha, over a wider area than last year (see map, below).
Millions of hectares of native vegetation have burned in this part of Siberia, releasing carbon and vast quantities of smoke. Firefighting in such a large and remote area is tough. Russian authorities have even tried to bring rainfall by The hot, dry conditions in Siberia have made trees and vegetation more vulnerable to fire, but the problem goes deeper.
“Not only is the surface layer of fuels drier, now we’ve got receding permafrost. The deeper soil layers used to be protected by cold, frozen, wet conditions. Now that permafrost is no longer there, allowing fires to penetrate deeper,” says Merritt Turetsky at the University of Colorado Boulder. How far down they go is poorly understood.
Some of those underground fires might even have been smouldering since last summer, leading them to be dubbed “zombie” fires. Researchers are still divided on how clear-cut the evidence is for such fires. But if field trips and satellite images confirm their existence, that raises the disturbing prospect of a short-term feedback loop where each bad fire year will add to the next one. “If what we speculated about zombie fires is true, then that is an ignition source that will most likely come into play next year,” says Parrington.
The smoke from the Russian fires is moving across Alaska, Canada and could eventually reach Greenland, says Parrington. One main pollutant it contains is carbon monoxide, which can stay in the atmosphere for about a month. For the 4 million people living in the Arctic, the effect of the smoke will be one of the most immediate impacts, says Phillips. The air pollution from the fires could even exacerbate respiratory problems in Russia, one of the countries worst hit by covid-19, which attacks the lungs.
Not all of the Arctic has been sweltering: Alaska and north-west Canada have been unusually wet and cold this year, and a and her colleagues confirmed that Alaska is getting wetter during summers. But in general, 2020 is a disaster year for the Arctic, the fallout from which will be global and play out over the long term.
Warming already appears to have turned the region from a carbon sink to a source of it (see “Can we rely on tropical forests to stop runaway climate change?”), and the burning of previously protected carbon underground will only accelerate climate change. The alteration in albedo – how much sunlight is reflected back into space – from bright ice turning into dark open water has the same feedback effect.
Climate models have long , but these are arriving sooner than expected. “To see an individual extreme year of the sort we have, and so soon, is very concerning,” says Meredith. “It’s as though some of our worst predictions for the future are being played out in front of our eyes.”
“Each of these events is exceptional. That they are occurring simultaneously should raise alarms”
There is still time to act, says Turetsky. “To me, this is a warning, a cry from the Arctic. This is our early beacon sign of what’s to come in terms of rapid climate change around the world. We can still stave off the worst consequences of climate change, but our window to do that is small.”
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