去年圣诞节，圣诞老人一定是穿着T恤和短裤往雪橇上装礼物。北极点的温度攀升至冰点，而正常温度应该是零下二十华氏度。今天留学群小编就给大家介绍一下托福听力科学美国人60秒 北极出现反滚雪球效应。
This is Scientific American — 60-Second Science. I＇m Julia Rosen.
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Last Christmas， Santa Claus must have been loading his sleigh in a t-shirt and shorts. Temperatures at the North Pole crept up toward the freezing point when they should have been minus twenty Fahrenheit.
The heat wave was the latest in a series that have swept over the Arctic in recent winters. Climate change has caused steady warming in the region. But it has also helped supercharge these extreme events， which scientists say are tied to storms that spiral north out of the Atlantic.
＂These winds actually pick up a lot of heat and moisture.＂
Vladimir Alexeev， a climate scientist at the University of Alaska Fairbanks.
＂And the atmosphere carries all this extra moisture and heat to the central Arctic， which results in [a] warmer and moister atmosphere.＂
Which then warms the surface.
Alexeev says the heat ferried north by these storms helps slow the growth of sea ice in winter—causing it to be about 15 centimeters thinner by the end of the season. And thinner ice may have a harder time surviving the summer.
But while the impact of these storms has grown in recent decades， the storms themselves are not happening more often， Alexeev says.
＂An important piece of information is that...