The record-setting heat wave that swept through Arctic Siberia in June has yielded a wide-range of deleterious effects in the expansive polar and sub-polar region, triggering raging wildfires, thawing permafrost, and now, spurring the rapid melt-out of Arctic sea ice.

Last month, Siberian temperatures spiked, reaching a record average more than 5 degrees Celsius (9 degrees Fahrenheit) hotter than normal, according to recently released data from the European Union. The remote town of Verkhoyansk in northeast Siberia recorded a reading of more than 38 degrees Celsius (100 degrees Fahrenheit) on June 17, the highest temperature ever recorded north of the Arctic Circle.

Under this metaphorical blow torch, ice extent in the seas that border Siberia has plummeted in recent days, pushing the Arctic region as a whole into the record books. Between July 2 and July 7, sea ice extent across the Arctic Ocean went from being at its fifth lowest extent for this time of year since satellite record-keeping began in 1979, melting into first place, slightly below even the calamitous year of 2012 which eventually saw sea ice hit a record low at the end of the summer melt season in September.

As of July 9, sea ice extent in the global Arctic sits at just 8.310 million square kilometers (3.2 million square miles). If that melting momentum carries forward (and nobody knows if it will), 2020 could nab the title of the lowest ice extent year come September with unknown long-term ramifications for the Arctic and the global climate.

An exceedingly abnormal spring and early summer in Siberia is thought to be largely responsible for 2020s sudden surge downward. The ice is opening up quite quickly and dramatically. Its now at a record low in the Laptev Sea off northern Siberia, says Walt Meier, a senior research scientist at the National Snow and Ice Data Center (NSIDC). At the end of June, sea ice extent in the Laptev Sea was more than 300,000 square kilometers (115,830 square miles) below the 40-year median for that time of year. On the North American side, its been closer to normal. In years past weve seen the waters quite open off the coast of Alaska, but were not seeing that as much this year.

A high-pressure system, bringing mostly cloudless weather, stalled over the Siberian Arctic throughout much of June, coinciding with the annual period when the High North observes 24 hours of daylight. The result: nearly continuous sunshine and record heat. Its quite a lot of energy hitting the ground, explains Meier. As Siberia warmed up, winds carried it out over the ocean, subsequently heating up Arctic waters and melting ice.

While air temperatures high above the Arctic Ocean were 1 to 4 degrees C (2 to 7 degrees F) warmer than average in June, things were a lot hotter along the Siberian coast. Air above the eastern edge of the Laptev Sea saw temps 8 degrees C (14 degrees F) higher, causing rapid melt. Meanwhile, the Kara Sea, off the Western Siberian coast, largely emptied of ice far sooner than normal.

This is kind of an exclamation point on the warming in Siberia, says Meier. The Arctic, as a whole, is warming two times faster than the rest of the world. Siberia is warming even faster.

In terms of how Siberia influences 2020s standing for this time of year, the damage is done, says Mark Serreze, director of the NSIDC. Already, sea surface temperatures are unusually high along the Siberian coast. This big head start to the melt season will yield more absorption of solar energy and more melting around Siberia. But just because things are bad there, that wont necessarily spell disaster for other parts of the Arctic.

Some years you get the big losses north of Siberia. Some years its around Alaska. It varies from year to year. This very much reflects weather patterns, explains Serreze. In recent years, the Bering Sea around Alaska has been the trouble spot. This year, the Siberian heat wave, which has waned for the moment, is hurting us big.

Avid ice bloggers point out that, in the record-breaking year of 2012, the biggest losses were also on the Siberian side of the Arctic, with a bit of exacerbated ice loss near Alaska.

But its still not possible to predict the future given the limitations of weather forecasting. Its looking like a warm year in the Arctic, says Meier. Its hard to say whether it will be a record-breaker for the sea ice. But the Siberian warming is an early indicator.

The heatwaves ill-effects arent confined to Siberias seas.

In mid-June, fiery infernos erupted in the regions boreal forests and tundra; the latter consists of permafrost soil that usually remains frozen but is now thawing due to escalating climate change. In fact, scientists speculate that some of 2020s tundra wildfires are actually leftover from last years fire season, silently burning within peat bogs throughout the winter, only to reemerge in spring eruptions dubbed zombie fires.

Last month, the EU Copernicus Sentinel-2 satellite picked up a wildfire in the Anabar district of Siberia, not far from the Laptev Sea believed to be the northernmost Arctic fire of recent years. While fires are common at this time of year, record temperatures and strong winds are making the situation particularly worrying, read a statement from the EUs Earth Observation Program.

Wildfires are often measured in terms of their heat output, and so far, 2020 rivals 2019, another disastrous fire year. The Russian government believes millions of acres of native vegetation in eastern Siberia have already gone up in flames, releasing 59 million metric tons of carbon dioxide into the atmosphere in June. Moreover, these fires are contributing to the thawing of the Arctic permafrost which, in some cases, can lead to sudden ground collapse.

The issue with fires in the Arctic is it burns above and below ground, explains Sue Natali, Arctic program director at Woods Hole Research Center. When surface soil rich in organic matter burns, it places the permafrost at risk which serves as an insulator against warm summer temperatures. In previously burned areas newly exposed to extreme summer heat events, it really pushes this system to the edge.

Ive seen this in Siberia in places that burned five years ago. You may get some vegetation coming back, but the ground is really vulnerable. When you get another warm year, theres extreme cracking of the ground and collapse, she says.

Natali is currently involved in a landmark research project using new elevation data and satellite imagery to map huge, mysterious craters some as much as 50 meters (164 feet) across first observed in the Siberian Arctic in July 2014.

It was something we had never seen before, says Natali, adding that researchers are unsure if theres a definitive link to climate change. Were trying to figure out whats causing these craters and where theyre going to happen next. The craters appear to form when thawed permafrost causes the ground to bubble up and explode, leaving deep depressions that then fill with water.

She notes that so far craters have only been observed in the Yamal and Gyda peninsulas near the Kara Sea. That is very likely because there are certain geologic conditions that may contribute to crater formation [subterranean] gas deposits and ground ice. That doesnt mean it cant happen anywhere.

Merritt Turetsky, director of the Institute of Arctic and Alpine Research at the University of Colorado Boulder, says, We know the fires burning in Siberia right now are in areas of continuous permafrost with high ice content. This is probably where well see rapid thaw in a couple years post-fires.

Permafrost thaw also puts the Arctic regions infrastructure and environment at risk. This was highlighted in late May by the devastating diesel spill at one of Russias Norilsk Nickel subsidiary power plants. A fuel tank suddenly collapsed and leaked 21,000 tons of diesel into the Ambarnaya and Dadylkan rivers, causing unprecedented damage to Arctic waterways. Russian officials have since traced the spill to thawing permafrost beneath the tank and ordered a full-scale review of infrastructure in vulnerable zones.

This was a huge disaster, says Natali, and it could be the first of many if precautions arent taken. In the permafrost zone, you have really important infrastructure like fuel storage tanks, buildings, sewage lagoons, dumps. All of these things can impact the health of those [people] who live on the permafrost.

Yet most local governments dont have a good idea of the ground beneath their feet. You would think they would want to have these permafrost areas mapped so they wouldnt put things like highways over ice-rich permafrost, which is more prone to sudden collapse, says INSTAARs Turetsky. There have been some whopper mistakes where huge construction projects in the North have been built on sensitive permafrost. It sure seems like that was the situation with the diesel spill.

Vladimir Romanovsky, a geophysicist at the University of Alaska Fairbanks, says this is especially concerning in Russia, where a huge amount of oil flows through pipelines crossing Siberias permafrost region. Any kind of interruption of this flow not only creates local emergencies and hazards for the environment, but can also impact global oil supply.

He adds that an overlooked concern is the rapid militarization of the Russian Arctic as the government strengthens its national security infrastructure in a region where the U.S. and Russian militaries eye each other suspiciously across the Arctic Sea.

How to keep this infrastructure in good shape in light of degrading permafrost is ultimately a matter of international security, concludes Romanovsky.

Banner image: Arctic sea ice in summer. Photo credit:NASA Goddard Photo and VideoonVisualHunt.com/CC BY

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Siberian heat drives Arctic ice extent to record low for early July - Mongabay.com