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 degrees Fahrenheit warmer than observed averages, scientists said, and at the pole itself, mean temperatures for the month were 23 degrees above normal. Although conditions later cooled somewhat, the extreme warmth is expected to return, with temperatures forecast to be as much as 27 degrees above normal beginning Thursday.
Jeremy Mathis, who directs the Arctic Research Program for the National Oceanic and Atmospheric Administration 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.
美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration，简称NOAA）北极研究项目负责人杰里米·马西斯(Jeremy Mathis)称，温暖导致北冰洋的冰冻时间晚于平常。那会造成明年春季和夏季的冰层覆盖达到历史纪录新低，而这又会导致气候更暖，因为会有更少冰面反射阳光，更多裸露的深色海洋吸收阳光。
“We’re going to be watching the summer of 2017 very closely,” Mathis said in an interview.
On Wednesday, 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.”
“我们目前观测到的这种温暖情况在如今的气候中依然是罕见事件，”英国牛津大学(University of Oxford)环境变化研究所(Environmental Change Institute)高级科学家弗里德里克·E·L·奥托(Friederike E.L. Otto)说，“但是，如果没有人为气候变化，这本是极不可能发生的事。”
The report, which includes findings from NOAA-sponsored research projects involving more than 60 scientists, was released last week at a scientific meeting in San Francisco. At a news conference, Mathis 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.