Arctic heat waves melt sea ice, which promotes more warming and even more ice loss. In other words, it’s a snowball effect—or in this case, an anti-snowball effect. Julia Rosen reports.

据朱莉娅·罗森（Julia Rosen）报道，北极热浪融化了海冰，这加强了气候变暖和海冰消失。换句话说，这是一个滚雪球效应——或在这种情况下，一个逆雪球效应。

撰文\播音：朱莉娅·罗森（Julia Rosen）

翻译：杨枭

审校：丁可含

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.

去年圣诞节，圣诞老人必须给他的雪橇马穿上T恤和短裤。当北极本应该为零下20华氏度时，温度却接近零度。

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.

在最近的冬天，热浪席卷了北极。气候变化已在该地区造成稳定变暖。而它也加剧促成一些极端事件，比如科学家所说的风暴盘旋着向北驶出大西洋。

“These winds actually pick up a lot of heat and moisture.”

“这些风实际上吸收了大量的热量和水分。”

Vladimir Alexeev, a climate scientist at the University of Alaska Fairbanks.

弗拉迪米尔·阿莱克谢耶夫（Vladimir Alexeev）是阿拉斯加大学费尔班克斯分校的气候科学家。

“And the atmosphere carries all this extra moisture and heat to the central Arctic, which results in [a] warmer and moister atmosphere.”

“气流将这些水分和热量带到北极中心，这导致了大气变得更加温暖和潮湿。”

Which then warms the surface.

然后大气温暖地表。

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.

阿莱克谢耶夫说，这些北上风暴所带来的热量加剧减缓冬季海冰的增长，将导致季节结束时冰层厚度减少约15厘米。更薄的冰可能无法在夏天幸存。

But while the impact of these storms has grown in recent decades, the storms themselves are not happening more often, Alexeev says.

但是，阿莱克谢耶夫表示，虽然最近几十年这些风暴的影响在增加，但风暴产生频率并没有便频繁。

“An important piece of information is that the frequency of those storms is not changing. What’s changing is the area of open water in those regions.”

“重要的是，这些风暴的发生频率没有改变。正在改变的是这些地区的开放水域。”

As the Atlantic Ocean has warmed up, the amount of sea ice around Scandinavia and Siberia in winter has decreased. So now, instead of passing over an ice-capped ocean, storms blow over larger areas of open water on their way north. And that gives them a chance to pick up more heat and moisture from the sea that they carry into the Arctic, causing stronger heat waves.

随着大西洋升温，冬季斯堪的纳维亚和西伯利亚的海冰量减少。所以现在，风暴不是越过一个冰雪覆盖的海洋，而是吹向北方更大的开阔水域。这让它们有机会从海洋中获取更多的热量和水分带入北极，造成更强的暖气流。

Alexeev presented his results in December at the Fall Meeting of the American Geophysical Union in San Francisco. [Vladimir A Alexeev, Warming in the Nordic Seas, North Atlantic Frankenstorms and thinning Arctic sea ice]

阿莱克谢耶夫于12月在旧金山的美国地球物理联盟秋季会议上发表了他的结果。

Another study by Kent Moore, an atmospheric physicist at the University of Toronto, came out around the same time as the meeting and also linked the heat waves to storms passing over more and more open water. That research is in the journal Scientific Reports. [G. W. K. Moore , The December 2015 North Pole Warming Event and the Increasing Occurrence of Such Events]

会议进行的同时，多伦多大学大气物理学家肯特·摩尔（Kent Moore）发表了另一项研究，也将热浪与风暴越来越多经过开放水域联系起来。这项研究是在期刊《科学·报告》上。

Alexeev says the situation could be an example of what scientists call a positive feedback: warming causes the loss of sea ice, which promotes more warming and even more ice loss. In other words, it’s a snowball effect—or in this case, an anti-snowball effect.

阿莱克谢耶夫说，这一情况可能是科学家称为正反馈的一个例子：变暖导致海冰的损失，这会促使气候更暖和更多的冰损失。换句话说，这是一个滚雪球效应——或在这种情况下，一个逆雪球效应。