Blame Heat Waves on Loss of Arctic Sea Ice

北冰洋的冬季從11月起直到次年4月，長達6個月。而夏季僅7、8兩個月。北極的冬天是漫長、寒冷而黑暗的，從每年的11月23日開始，有近半年時間是幾乎看不見太陽的日子。到了4月份，才慢慢暖和起來，冰雪逐漸消融。而北極地區的夏季卻出現了劇烈的冰融現象，科學家對此研究表明，這與熱浪期有著一些聯系。

In the summer of 2012， the U.S. was baked. From the end of June to the end of July， temperature records were set across the middle of the country. And the cause may have been the record-setting meltdown of Arctic sea ice.

The loss of sea ice leads to a weakening of winds high in the atmosphere. The reduced temperature difference between the Arctic and lower latitudes diminishes the jet stream as well. It also moves the jet stream north， letting hot air sit longer.

Such a lessening of the jet stream may have been responsible for Hurricane Sandy turning ashore and wreaking havoc in New York City and New Jersey. And the phenomenon extends beyond North America. Weak jet streams have prolonged heat waves in Russia as well as parked downpours over Europe.

One thing’s for sure： increasing concentrations of greenhouse gases in the atmosphere will continue to warm the Arctic and melt ice and snow. And that could mean much hotter summers across the northern hemisphere.

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