The research, published on Friday in the journal Scientific Reports, comes amid growing concern about the warming of Greenland, Siberia, Alaska and other far northern regions, which have recently experienced unusually prolonged and frequent midwinter temperature spikes.
The authors from the University of California, Davis, based the study on temperature records and 743 previous phenological studies looking at timings of bird migrations, flowers blooming and amphibians calling. The results showed a curve, with spring events occurring earlier further north of the equator.
“Spring is arriving earlier, and the Arctic is experiencing greater advances of spring than lower latitudes,” said lead author Eric Post, a fellow of the John Muir Institute and polar ecologist at UC Davis.
Over the past 10 years, this means the end of winter will come about a day earlier in Los Angeles, but two weeks earlier in the Arctic. The authors say the northward increase in the rate of springtime advance is roughly three times greater than indicated by previous studies.
This underlines how pronounced climate change is in the Arctic, where temperatures are rising twice as fast as the global average and ice fields are rapidly shrinking.
The warming trend has been unusually apparent in recent weeks. Although the sun has not reached the high Arctic since October, temperatures has been above freezing for 61 hours – more than three times the previous record – at Greenland’s northernmost weather monitoring station.
Martin Stendel, lead scientist of the Polar Portal and a senior researcher at the Danish Meteorological Institute, said temperatures in the central Arctic have been 4C warmer than average this winter. In February, several regions were 10C above historic norms. Despite fluctuations, he expects this trend to continue.
“Think of waves on the beach. Some are high, some are low. That’s the weather. But in the background the tide is coming in. That’s climate change. Even though the waves haven’t changed their properties, they come closer and closer to your feet,” he says. The consequences would include increased melting of the ice sheet, less sea ice, thawing permafrost both on land and under the sea, less snow and more rain even in winter.
The weather has appeared out of joint seasonally and geographically. As much of northern Europe was hit by blizzards and chills, the Danish media joked that residents should visit the Arctic special forces base at Daneborg because it is warmer there.
The Information newspaper interviewed a member of the Sirius Dog Sled Patrol at the base – one of the most northern permanent outposts of humanity – who said the high temperature had turned slow into slush and made sledding heavy.
The handful of troops at the base are used to spending months in cold and darkness. “The first day the sun doesn’t come up you think ‘Wow’,” one member told Greenland Today in 2015. “The water and the rivers stop running because they freeze. The fjord freezes too, so there are no waves or swells that lap at the shore. The small birds fly south so there is no birdsong. Only the ravens overwinter. And then a thick layer of snow comes that muffles everything even more.”
On some patrols, they encounter blizzards that last for days and temperatures as low at -51C.
But there is increasingly frequent respite in the form of warm “foehn wind”. This abrupt warming and drying of moist winds as they pass over ice-masses or mountains is commonly seen in the Alps. Similar phenomenon are the Chinook or “snow eater” of the North American Rocky Mountains; the Zonda of the South American Andes; and the Helm wind of the English Pennines.
February has seen such warmth arrive with unprecedented frequency.
One member of the Arctic Patrol described the effect as surreal. “Outside, the dogs lie on their backs boiling and we dance around in our underwear enjoying it, until the cold returns.”
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