日批在线视频_内射毛片内射国产夫妻_亚洲三级小视频_在线观看亚洲大片短视频_女性向h片资源在线观看_亚洲最大网

Arctic sea ice shrinks, ice free summer looms

Updated: 2011-09-02 20:04

(Agencies)

  Comments() Print Mail Large Medium  Small 分享按鈕 0

OFF SVALBARD, Norway - Arctic sea ice cover has already shrunk to its third lowest level on record this year, in an irreversible trend which may see an ice-free summer around 2030, said the head of the world's main monitoring centre.

The sea ice area will be reduced further in the next two weeks but was unlikely to beat a 2007 retreat in a 32-year satellite data record, said Mark Serreze, director of the US-based National Snow and Ice Data Center. ?

While sea ice does not raise sea levels when it melts, just as melting ice in a glass of water, an ice-free summer would have implications for the exploitation of resources in the area, scientists say. It could also disrupt weather patterns or cause the Greenland ice sheet to melt more rapidly.

Exxon Mobil Corp and Rosneft signed an agreement on Tuesday to extract oil and gas from the Russian Arctic, in exploration which may be assisted by the recent trend of summer sea ice retreat north of Russia. ?

"The numbers today are saying that if all further melt stopped right now it would be the third most in the satellite record," Serreze said on Thursday. ?

"We just dropped below 4.6 million square kilometres and that's what we had in 2010 (at the minimum). We're continuing the overall pattern of loss, and there's still a couple of weeks to go in the melt season."

"Will we break the record in 2007? I don't think so but we're going to be close."

Sea ice floats in water and covers the North Pole, as distinct from ice sheets resting on land. The Greenland ice sheet contains the equivalent of about 7 metres sea level rise if it all melted. ?

The five biggest summer sea ice retreats have all been in the past five years, in a satellite record dating back to 1979, a trend which most scientists attribute to manmade warming.

The ice usually hits a minimum around mid-September each year, before growing again as cold winter weather returns.

The warming is exaggerated by an albedo effect where more open water without ice reflects back into space less sunlight, warming the local area more, leading to more open water, and so on.

Satellite readings also suggest that the sea ice is thinning, say researchers at NSIDC and other institutes, but such readings are less certain than the measurement of area. ?

"Everything we look at is all pointing in the same direction. Is Arctic ice cover thinning, absolutely it is, hand in hand with extent," Serreze said. ?

"The long-term picture is very, very clear. There's no going back now."

Most scientists agree that the Arctic is on track to be completely ice-free in summer at some point this century, with sharp disagreement about exactly when. Having an ice-free summer in 2030 was "not unrealistic", Serreze said. ?

Some climate sceptics have pointed to the shortness of the satellite record to cast doubt on identifying a new Arctic sea ice trend, or to blame man-made climate change.??

主站蜘蛛池模板: 国产精品久久久久av | 好吊操在线 | 亚洲视频在线一区 | 亚洲欧美系列 | 国产精品久久一区二区三区 | 国产一区91精品张津瑜 | 亚洲人成小说 | 中文字幕在线观看91 | 超碰天天 | 日本女人黄色片 | 国产激情福利 | 在线观看精品国产 | 日本一二三区在线视频 | 单身男女免费观看国语高清 | 国产精品国产精品国产 | 亚洲成人黄色网址 | 亚洲更新最快 | 国产成年人在线观看 | 免费网站在线播放 | 久久精品99国产国产精 | 91插插插影库永久免费 | 日韩在线视频一区 | 在线观看天堂av | 中文字幕永久在线 | 激情综合色 | 欧美第九页 | 免费高清成人 | 激情综合图区 | 日韩一区二区在线观看 | 手机在线观看av | 超碰在线观看99 | 免费成人深夜天涯网站 | 中文字幕二 | www.五月天激情 | 在线一区二区三区四区 | 视频一区二区三区在线 | 日本男人天堂 | 日韩免费精品 | 性欧美疯狂猛交69hd | 天天操免费视频 | 亚洲人免费视频 |