How the Arctic Circle just eclipsed 100 degrees
It’s triple digits in the polar realm.
BY MARK KAUFMAN
Temperatures hit triple digits at a Russian town in the Arctic Circle on Saturday, either breaking or nearly breaking the hottest temperature on record in this polar realm.
Preliminary observations, spotted by French meteorologist Etienne Kapikian, show the heat reached 100.4 degrees Fahrenheit in the Siberian town of Verkhoyansk (which would eclipse an Arctic Circle record set over a century ago, in Alaska). That’s over 30 degrees warmer than usual for Verkhoyansk in June.
In the relentlessly warming 21st century, it’s increasingly common for heat records to get broken. High temperature records today far outpace new low temperature records. Now, the potentially record heat in Siberia has created ideal conditions for robust fires that are releasing bounties of heat-trapping carbon into the atmosphere.
What caused such extreme heat in Siberia? It’s a combination of a hot weather pattern and climate change.
Temperatures haven’t just been unusually warm in Siberia recently — they’ve been atypical for nearly six months now. “It’s been remarkable to watch the persistent warmth (relative to average) continue over Siberia since early winter,” said Zachary Labe, a climate scientist at Colorado State University’s Department of Atmospheric Science.
But with summer comes the potential for extreme heat.
Weather is a dominant factor in Siberia’s current temperatures. A big mass of warmer air is stuck over the area. These stubborn, slow-moving weather patterns can stall over a region and result in extreme temperatures — much like last year’s record-breaking heat waves in Europe.
This region of warmer air has been facilitated by the jet stream, a relatively narrow band of high altitude, powerful winds traveling some four to eight miles up in the atmosphere. Like a barrier, this band of west traveling winds separates colder northern air from warmer southern air. But this potent stream of winds can bend and curve, undulating “like a meandering river,” explained Andreas Muenchow, a physical oceanographer at the University of Delaware. Over Siberia, the jet stream has meandered northward, bringing warmer air where it usually is not, he said.
Yet, climate change plays an influential role in these extreme events, too. The planet is heating up as human civilization saturates the atmosphere with the highest levels of heat-trapping carbon dioxide in at least 800,000 years. This amplifies warming extremes, making them hotter than they otherwise would be. Extreme, anomalous temperatures are especially the case in the Arctic, one of the fastest-warming regions on Earth.
“The long-term rising temperature of the Arctic increases the probability (or chance) for these types of record warm events,” said Labe.
What’s more, a heating Arctic often makes warmer weather events even warmer by melting the Arctic’s great cap of sea ice. White sea ice reflects energy from the sun back into space. But when the ice melts due to warmer temperatures, the dark ocean will instead absorb this heat, which then warms up the ocean surface and ultimately the air, too. This amplifies overall warming in the Arctic region, a trend that will almost certainly continue as sea ice continues to diminish. “The 13 lowest [sea ice] extents in the satellite era have all occurred in the last 13 years,” the National Snow and Ice Data Center said last year.
Siberia’s overall warming this year, too, is a consequence of both warmer weather events and a heating climate. This year, Siberia has been a whopping 7 degrees Celsius (about 13 degrees F) above average. Flavio Lehner of the National Center for Atmospheric Research estimated last week that of the 7 degrees C of above-average temperatures, between 2 to 2.3 C came from human-caused warming of the planet.
As is often the case, climate change doesn’t cause extreme weather events — it makes them worse or more severe.
Originally published at https://mashable.com
