Arctic climate goes off the rails

Arctic climate goes off the rails

Wildfires, record warmth and rapidly melting ice: Arctic climate goes further off the rails this summer

Records shattered in Siberia, Svalbard, Nunavut and other areas as study points to historic shifts.

Andrew Freedman

Washington Post,

July 30, 2020 

The Arctic summer of 2020 is one that has been marked by raging fires in the Far North, with smoke extending more than 1,000 miles downwind, along with alarming new temperature records and ice melt. While rapid Arctic climate change is not exactly news — the region is warming at about three times the rate of the rest of the world — the manifestations of this phenomenon are increasing in severity, scope and societal consequences.

This week, for example, with blazes raging across Siberia, smoke smothered the skies all the way into portions of Alaska. In Svalbard, a Norwegian Arctic archipelago that has seen staggering warming rates in recent years, all-time temperature records were set, turning already receding glaciers into mush, covered by so much turquoise meltwater that it was visible from space.

The Svalbard archipelago is one of the fastest-warming places on Earth, with sea ice and glaciers on the decline. In Longyearbyen, Svalbard, the northernmost inhabited settlement, with more than 1,000 residents, temperatures soared to 71.1 degrees (21.7 Celsius) on July 25, setting a record high for this location. Longyearbyen had a string of four days that exceeded 68 degrees (20 Celsius). Such a high temperature had only been seen once before, in July of 1979.

At the same location, the overnight low temperature failed to fall below 62.2 degrees (16.8 Celsius) on the 28th, setting a record for the warmest low temperature. This is 6.3 degrees (3.5 Celsius) warmer than the previous record, which was set just two days prior, on July 26.

The average high and low temperatures at this time of year in Longyearbyen are 49 (9.4 Celsius) and 41 degrees (5 Celsius)

The ice cap in Svalbard has the highest surface mass loss of any Arctic ice sheet so far this summer and hit a record for its daily melt rate on July 25, when temperatures spiked, said Xavier Fettweis, a scientist at the University of Liège, Belgium. “With respect to the average, the melt has been 4 times larger than normal and it is the highest rate” on record since at least 1980, Fettweis said via email.

He added that the last several days in July 2020 brought the highest temperatures seen over the permanent ice area across the archipelago.

Meltwater seen on glaciers in Svalbard, Norway, comparing images from July 27, 2019, with July 27, 2020. (European Union, Copernicus Sentinel-2 imagery processed by Annamaria Luongo)

Meltwater seen on glaciers in Svalbard, Norway, comparing images from July 27, 2019, with July 27, 2020. (European Union, Copernicus Sentinel-2 imagery processed by Annamaria Luongo)

Comparison of images of glaciers in Svalbard, Norway, on July 27, 2019, vs. July 27, 2020. (European Union, Copernicus Sentinel-2 imagery processed by Annamaria Luongo)

Comparison of images of glaciers in Svalbard, Norway, on July 27, 2019, vs. July 27, 2020. (European Union, Copernicus Sentinel-2 imagery processed by Annamaria Luongo)

Fettweis says the exceptional warmth and ice melt in Svalbard are a result of the record warm air present across the Russian Arctic, since weather patterns have drawn this air northward. He also cited earlier than average sea ice melt, with virtually no sea ice present in the area during July. The ice normally puts a lid on summer temperatures.

Arctic wildfire emissions set records

While Siberia’s extreme temperatures — including a likely all-time Arctic temperature record of 100.4 degrees (38 Celsius) recorded in June in Verkhoyansk, which lies above the Arctic Circle — has received the most attention, it’s the wildfires there that are having ripple effects far beyond this region. These fires have continued on their relentless pace since June.

Each day, smoke, containing planet-warming greenhouse gases, has poured into the air, while on the ground flames have been destabilizing permafrost by burning away protective vegetation above the permanently frozen soil. This, too, adds to climate change, since it frees up carbon and methane.On many days during July, a milky sheen of smoke thick enough to obscure the ground was visible on satellite imagery extending across an expanse that would cover much of the Lower 48 states. The most severe fires have been accompanied by towering smoke plumes, known as pyrocumulonimbus clouds, or pyroCbs.

Arctic wildfire carbon emissions, driven primarily by Siberian fires, hit a record level in July, according to the Copernicus Atmosphere Monitoring Service, a European Union science agency based in Reading, England. Such data stretches back 18 years, with an increase in Arctic fire emissions seen during that period.

Smoke snakes across Siberia, toward the northwest Pacific Ocean on Monday. Some smoke is also flowing toward Arctic sea ice. (NASA Worldview)

Smoke snakes across Siberia, toward the northwest Pacific Ocean on Monday. Some smoke is also flowing toward Arctic sea ice. (NASA Worldview)

Between July 1 and July 23, the estimated July total carbon emissions from fires in the Siberian Arctic amount to 100 metric megatons of carbon dioxide, said Mark Parrington, a senior scientist with the Copernicus Atmosphere Monitoring Service, via email. Parrington said this is on top of the 59 metric megatons of carbon dioxide emitted from Arctic Circle fires in June.

“The large cluster of fires in well within the Siberian Arctic Circle has been burning with high intensity (higher than the highest daily total calculated for the region in 2019) for several days and look set to continue,” Parrington said last Friday, a prediction that has turned out to be true.

Via Twitter on Wednesday, Parrington said: “July 2020 has witnessed escalation in Arctic fires previously unseen” in data gathered by the Copernicus Atmosphere Monitoring Service. Satellite-estimated wildfire carbon emissions, Parrington said, are running at twice the amount seen during the previous record Arctic fire season, which was last year.

Smoke from these fires, including ash and carbon monoxide, spread across the Chukchi Sea as far as Alaska.

Siberia has experienced record warmth for the calendar year so far. The Siberian fires and, in particular, the prolonged heat have already been directly tied to human-caused climate change.

In a rapid analysis, researchers found that the prolonged January-to-June heat in northern Siberia was made at least 600 times as likely by human-caused climate change. This led them to conclude that such an event would be nearly impossible in the absence of global warming.In addition, other parts of the Arctic are reeling from climate change-related effects, along with transient weather features.

Meanwhile, the extreme temperatures in the Scandinavian Arctic and Siberia have spilled over to northern Canada, too. On July 25, a temperature of 71.4 degrees was recorded in Eureka, Nunavut, located in the Canadian Arctic at 80 degrees north latitude. According to Mika Rantanen, a researcher at the Finnish Meteorological Institute, that may be the highest temperature on record so far north.

In an example of how extreme weather events can interact with long-term climate change-related trends, a strong low-pressure area spun up early this week over the Beaufort Sea, north of Alaska, potentially hastening sea ice melt. The low is reminiscent of a powerful storm that churned the sea ice cover during the summer melt season of 2012. That storm helped to accelerate ice loss, leading to an all-time, record-low ice extent.

Despite being of similar intensity, the recent storm is unlikely to have the same effects on the trajectory of the melt season, sea ice experts say. While noting that sea ice extent is in record-low territory, the storm struck a region full of the thickest ice in the Arctic. Most of the ice loss this summer has come on the Eurasian side of the Arctic, including north of Siberia, where the Northern Sea Route very probably opened at its earliest date on record, a full month earlier than average.

“The key really is the timing of the storm and the thickness of the ice that’s there,” Julienne Stroeve, a senior scientist at the National Snow and Ice Data Center (NSIDC) in Boulder, Colo., said in an email.

There is a chance that the storm could speed up ice melt, but it depends on a number of factors.

“Since storms tend to cause ice divergence, if the storm pushes some of the ice in the Beaufort [Sea] towards [the] Bering Strait then it will likely melt out, as the ocean temperatures there are up to 5 Celsius warmer than average,” Stroeve said.

Walt Meier, an NSIDC colleague of Stroeve’s, noted that the 2012 storm struck later in the melt season and in “a region where the ice cover was already broken up and was fairly disperse (low concentration). So there was a lot of opportunity for the storm to kick up waves and really decimate the ice. This year, the ice in that region is, at least at the moment, looking more formidable. It’s more compacted and likely thicker. So this year’s storm may not have the same impact as in 2012. We shall see.”The bottom line

Almost uniformly, scientists studying Arctic warming emphasize how swiftly changes are occurring throughout the vast region. A study published Wednesday in Nature Climate Change backs up that impression, showing that “major portions” of the region have been warming at a rate of 1.8 degrees (1 Celsius) per decade for 40 years, which constitutes an “abrupt climate change event” when viewed in light of paleoclimate records of abrupt glacial episodes in the past.

The study found that even the direst climate model scenarios tend to underestimate the recent pace and extent of climate change in the Arctic. Co-author Martin Stendel, a research scientist at the Danish Meteorological Institute, wrote via a Twitter message that “[a]dditional abrupt changes can only be avoided following a low emission scenario.”

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