Spiking temperatures in the Arctic startle scientists

A  spate of extreme warmth in the Arctic over the past two months has startled scientists, who warn that the high temperatures may lead to record-low ice coverage next summer and even more warming in a region that is already among the hardest hit by climate change. In mid-November, parts of the Arctic were more than 35° Fahrenheit (F) warmer than observed averages, scientists said, and at the pole itself, mean temperatures for the month were 23° F above normal.

Although conditions later cooled somewhat, the extreme warmth is expected to return, with temperatures forecast to be as much as 27° F above normal. Jeremy Mathis, who directs the Arctic Research Programme for the National Oceanic and Atmospheric Administration (NOAA), USA said the warmth had led to a later than usual “freeze-up” of ice in the Arctic Ocean. That in turn may lead to record-low ice coverage in the spring and summer, which could lead to more warming because there will be less ice to reflect the sun’s rays and more darker, exposed ocean to absorb them.

Recently, researchers released a study linking the abnormally high Arctic temperatures to human-caused climate change. Using simulations of the climate, both current and before widespread carbon emissions, they found that the likelihood of extreme temperatures like those that occurred this fall had increased to about once every 50 years from about once every 1,000 years. “A warm episode like the one we are currently observing is still a rare event in today’s climate,” said one of the researchers, Friederike E L Otto, a senior scientist at the Environmental Change Institute at the University of Oxford in Britain. “But it would have been an extremely unlikely event without anthropogenic climate change.” What’s more, Friederike said, if climate change continues at its current pace, spates of extreme Arctic warmth may become common, on the order of once every two years.

Walt Meier, a research scientist at NASA’s Goddard Space Flight Centre, said that the current warmth had been brought on by fluctuations in the jet stream, which have allowed frigid air to make its way south into North America and warm air into parts of the Arctic. While such outbreaks of extreme warmth are not new, he said, there are many signs that climate change is making them more frequent. While the earth overall has been warming, the Arctic has been warming at least twice as fast as the global average. In part, scientists say, that is because of declines in sea ice coverage. Ice typically reflects from about half to 70% of the solar energy that hits it, but water reflects only 6%, and so the water warms up. That melts more ice, which in turn leads to more exposed ocean and still more melting.

The recent high temperatures have had a severe impact on Arctic sea ice formation this fall. Ice coverage was the lowest for any November since satellite records began in 1979, NOAA said. Sea ice is also getting thinner on average, as thicker, multiyear ice melts and is replaced by ice that lasts only a year. Temperatures this fall were so far off the charts that NOAA took the unusual step of extending the time frame for its annual ‘Arctic report card’ by a few days into early December. The report, which includes findings from NOAA-sponsored research projects involving more than 60 scientists, was released recently at a scientific meeting. At a news conference, Jeremy said that in addition to the extreme warm periods, the overall year was the warmest on record. “We’ve seen a year in 2016 in the Arctic like we’ve never seen before,” he said.

Jeremy also noted that warming effects in the Arctic have had a cascading effect through the environment, “including down into Arctic ecosystems.” He said that communities that rely on hunting and fishing for their food security “should be very concerned.” “It’s getting harder and harder for them to harvest resources as the ice pulls back further and further away from the coast,” he said. But Jeremy added that changing conditions in the far north should concern everyone. “We need people to know and understand that the Arctic is going to have an impact on their lives no matter where they live.”