今年5月初，美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration）全球卫星观察系统的研究人员发布了上述报告。国家海洋和大气管理局的杰夫·基（Jeff Key）说，“今年冬季北极的冰川面积低于卫星观察时期的任何时期。”

卫星观察从1979年开始，通过观察获得的地球观察数据向国际科学家广泛公开。国家海洋和大气管理局的杰夫·基等科学家根据长期观察的趋势又有了新的发现。杰夫·基在华盛顿（Washington）举行的一次简报会上表示，“我们现在不仅了解到 北极的冰原逐渐变薄，而且还确切地知道过去30年发生这种情况的地点、规模和程度。”

杰夫·基说，上述情况并非属于偏远地区的一件小事。北极的状态可以决定低纬度地区的天气情况，是具有深远影响的因素之一。

北极气候变暖也会改变航行、捕捞、农业及石油和矿物开采等活动的条件。证据表明，野生生物也会因此受到不利影响。

但这仅仅是开始。杰夫·基说，“冰雪面积的变化可以影响水供应。水供应对很多特别干旱的国家来说具有十分重大的意义。一个重大的影响是，冰川融化可造成海平面上升，对全世界任何地区的海案城市都会造成影响。”国家海洋和大气管理局在公布2014年北极年度报告（Arctic Report Card for 2014）仅几个月后就发现了上述情况。

根据2014年北极年度报告，北极气温上升的速度高于全球气温的一倍以上。这类科学报告都经过核实和同行评估，为2013年宣布的美国气候行动计划（U.S. Climate Action Plan） 提供了依据。这项战略要求降低造成气候变化的温室气体排放，实现清洁能源经济。


A crime against nature: The case of the disappearing ice

The Arctic lost 1 million square kilometers of ice between winter 2014 and winter 2015.

Arctic sea ice covered about 14.5 million square kilometers at its peak in the winter of 2015. You might think that makes for one gargantuan skating rink, but during most winters Arctic sea ice covers even more territory — 15.6 million square kilometers on average.

The keepers of global satellite observations at the National Oceanic and Atmospheric Administration (NOAA) reported those findings in early May.

“We had less ice this winter in the Arctic than any other winter during the satellite era,” said NOAA’s Jeff Key.

Satellite observations began in 1979, and international scientists widely share their Earth observation data. Looking at the long-term trends, Key and other NOAA scientists have made another new finding.

“We now know that not only has the Arctic ice pack been thinning, but we know exactly where and to what magnitude and what degree over the last 30-plus years,” Key said at a Washington briefing.

This is not just interesting trivia about a remote place. Arctic conditions can determine weather events in lower latitudes, Key said, only one of many far-reaching effects. A warmer Arctic climate also can change operating conditions for enterprises such as shipping, fishing, agriculture, and oil and mineral extraction. Negative impacts on wildlife are well documented. And that’s just the beginning.

“Changes in snow cover impact water supply, which is very important to many especially arid countries,” Key said. “The big [impact] is that melting ice sheets cause an increase in sea level or a sea level rise, and that’ll impact any coastal city anywhere in the world.”

These results come only months after NOAA scientists issued the Arctic Report Card for 2014, which produced evidence that Arctic air temperatures are rising at more than twice the rate of global air temperatures.

Verified, peer-reviewed scientific findings of this kind form the basis of the U.S. Climate Action Plan announced in 2013. The strategy calls for reducing the greenhouse gas emissions that contribute to climate change and moving to a clean-energy economy.