The Arctic Heat Wave: Why is it so hot in the Arctic right now?

Over the weekend, Verkhoyansk, Russia reached a temperature of 100.4 degrees Fahrenheit. Researchers are still working to confirm the result, which may be recognized as a record for the Arctic Circle.

And the small Siberian town is not alone. Much of Russia has faced a heat wave in recent days, with multiple locations reporting temperatures as high as 113 degrees on June 19. The surprising heat was also felt in other parts of the Arctic such as northern Canada and Scandinavia.

It is part of a pattern of high temperatures this year in what are normally some of the coldest parts of the planet. The current scorching climate in the region will have global consequences and heralds the future of the Arctic and the planet as the climate changes.

Russia is emerging from its hottest winter on record, and since the beginning of the year, temperatures have averaged 12.4 degrees Fahrenheit above what is typical in Siberia.

And this polar heat has led to a number of problems for the region, from a major oil spill from the melting of permafrost to the first forest fires north of the Arctic Circle in Russia and Alaska.

Several key factors have aligned in recent months to warm the Arctic. And they are adding to long-term warming trends. That means that more of this type of heat is likely in the future, as is defrosting, fires, and weather disruption.

Why are parts of the Arctic so hot right now?

The term “heat wave” is a relative measure. Temperatures that count as a heat wave differ depending on the regional climate. It is generally defined as temperatures above the 95th percentile of the historical distribution of a region.

So the bar for a heat wave in the Arctic is considerably lower than at lower latitudes. But recent temperatures in the extreme north would be stifling almost anywhere.

A heat wave begins with high atmospheric pressure that builds up over an area. A downward moving column of air compresses the air that is closest to the ground, keeps it still, and heats it up. That high pressure also forces the clouds to move away and surround the column, creating an unobstructed line of light between the ground and the sun.

Over a period of days and weeks, the soil absorbs sunlight, and with stagnant air, heat builds up and temperatures rise. “There is nothing going in and nothing going out,” said Walt Meier, a senior scientific researcher at the National Snow and Ice Data Center at the University of Colorado Boulder. “It’s basically like an oven.”

That is the general formula for heat waves around the world. But there are also several unique ingredients that contribute to the Arctic.

In the northern latitudes during the summer, there is almost continuous sunlight, even at night. That allows heat to build up faster than in areas that experience sunsets and can cool down at night.

Another factor this year was the lack of snow. With an unusually warm winter, less snow accumulated in parts of the Arctic, and with a warm spring, much of it melted earlier than usual. “Snow reflects a lot of sunlight,” said Meier. “This year, the snow was gone earlier, so you have bare soil that can absorb more solar energy.”

The warmer soil also dries out in the heat. With less humidity, there is less evaporation that can cool the surrounding air. “The drier soil and the air above it makes it more susceptible to rapid warming when you have the right conditions like what we are seeing now,” Meier said.

The Arctic heat wave highlights the looming impacts of climate change.

For the Siberian heat wave, the past can be a prologue. Last year, amid temperatures that were 14 degrees Fahrenheit above the long-term average for the region, forest fires burned in a near-record area, sending suffocating smoke to cities like Novosibirsk, Russia’s third-largest city. Feathers even made it to the western United States.

Siberia also saw massive fires in 2018, 2017 and 2016. Forest fires occur naturally in Siberia and can occasionally spark north of the Arctic Circle, often lightning-stricken in dry forests in the summer months. But the flames in recent years have been unusually large and close to population centers. Fires burning in the region could now continue to spread as the summer season further warms the region.

One of the general trends behind the heat wave and forest fires is climate change. The Earth as a whole is warming due to human emissions of greenhouse gases like carbon dioxide. But each place does not heat up at the same rate; The Arctic is warming at twice the rate of the rest of the planet, so some of the first effects of climate change are being felt in the region. The north pole also presents a window into the future for the rest of the world.

Workers in Norilsk, Russia clean up an oil spill caused in part by the melting of the permafrost.
Denis Kozhevnikov / TASS via Getty Images

Those higher average temperatures mean that extreme heat will be even more likely and more intense, exacerbating threats such as forest fires as the vegetation dries up. “Forest fires definitely come from extreme heat and dryness,” said Meier.

The loss of these ancient and slow-growing forests will release carbon dioxide into the atmosphere that will take decades to re-absorb, further heating the planet. Warming in the Arctic is also thawing permafrost, which releases even more carbon into the atmosphere.

And although it is summer in the Arctic right now, the region has also experienced heat waves in the winter. In fact, researchers have found that winters generally heat up faster than summers. That’s part of the reason the Arctic is now losing sea ice at its fastest rate in 1,500 years.

Graph showing annual decline in Arctic sea ice

Christina Animashaun / Vox

Antarctica is also heating up. Earlier this year, the continent broke two high temperature records in one week.

With average temperatures about to rise further, more heat, thaw, melt and fire await the Arctic. “This year he is in Siberia. Next year it could be in Alaska or Northern Canada or Scandinavia, “said Meier. “On average, what we consider extreme events will become more and more normal.”

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