Arctic Ocean could be source of greenhouse gas：study 研究︰北冰洋可能是溫室氣體的來源

Arctic Ocean could be source of greenhouse gas：study 
研究︰北冰洋可能是溫室氣體的來源
2012-04-25◎ 魏國金

The Arctic Ocean could be a significant contributor of methane, a powerful greenhouse gas, scientists reported.
北冰洋可能是威力強大的溫室氣體「甲烷」的重要產生源，科學家報告指出。

Researchers carried out five flights in 2009 and 2010 to measure atmospheric methane in latitudes as high as 82 degrees north.
研究人員在2009與2010年間，於高達北緯82度的區域進行5次飛行，以測量大氣甲烷。

They found concentrations of the gas close to the ocean surface, especially in areas where sea ice had cracked or broken up.
他們在接近北冰洋海面，特別是海冰破裂或裂解的地區發現高濃度甲烷。

The study, published in the journal Nature Geoscience, wonders if this is a new mechanism that could accelerate global warming. If so, the Arctic Ocean would add to several identified "positive feedbacks" in Earth’s climate system which ramp up the greenhouse effect.
這份發表在「自然地球科學」期刊的研究懷疑，是否這可能是加速全球暖化的新機制。果真如此，北冰洋將增加數個已被確認會大幅增強溫室效應的地球氣候系統之「正回饋」。

One such vicious circle is the release of methane from Siberian and North American permafrost. The thawing soil releases methane that has been locked up for millions of years, which adds to global warming -- which in turns frees more methane, and so on.
一個正回饋的惡性循環就是西伯利亞與北美永凍層的甲烷釋出。這個持續解凍的土層釋放出封存數百萬年之久的甲烷，因而增加全球暖化，這反過來又釋出更多甲烷等等。

But this is the first evidence that points to a methane contribution from the ocean, not the land, in Arctic latitudes.
然而這是第一個指出北極區海洋，而非陸地是甲烷生產源的證明。

Levels of methane in the atmosphere are relatively low, but the gas is 20 times more effective that carbon dioxide（CO2）at trapping solar heat. （AFP）
大氣的甲烷濃度相當低，不過該氣體捕捉太陽熱氣的效能是二氧化碳（CO2）的20倍。（法新社）

新聞辭典

ramp up︰片語，明顯增加、增強。例句︰Many countries have ramped up airport security.（許多國家已大幅加強機場安全措施。）

vicious circle︰名詞，惡性循環。例句︰The high growth of oil and electricity prices could produce a vicious circle of inflation.（油電價格的高漲恐造成通貨膨脹的惡性循環。）

in turn︰片語，轉而、反過來，也有依序之意。例句︰We were summoned in turn to see the boss.（我們依序被老闆召見。）