The Arctic sea ice holds a central position in the Earth's climate system and it's deteriorating faster than expected.

北极海冰在地球气候系统中占据中心位置，并且它恶化的速度比预期的更快。

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Arctic sea ice usually melts in spring and summer, then grows in winter.

北极的海冰通常在春天和夏天融化，然后在冬天形成。

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Arctic sea ice has also retreated at a faster than average rate.

北冰洋海域的冰雪正以超过平均速度的速度溶逝。

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The two government agencies have been studying Arctic Sea ice from space since nineteen seventy-nine.

VOA: special.2009.05.05

The analysis produced a summer Arctic sea-ice minimum extent of 6.9 million sq km.

BBC: Earliest satellite maps of Antarctic and Arctic sea-ice

It is widely expected Arctic sea-ice will be totally lost in summer with a few years to a decade or so, perhaps at less than 1C or warming.

FORBES: Breaking News: The Climate Actually Changes!

According to the US National Snow and Ice Data Center (NSIDC), Arctic sea-ice covered 4.5 million sq km (1.7 million sq miles) at its lowest point on 12 September last year.

BBC: Arctic team targets key ice data