Methane escaping from Arctic faster than expected and could stoke global warming, warn scientists
By Daily Mail Reporter
Last updated at 3:32 PM on 05th March 2010
Researcher Katey Walter lights a pocket of methane on a lake in Siberia showing just how explosive the greenhouse gas is
研究員凱蒂沃爾特在西伯利亞湖上燃點一袋的甲烷，顯示溫室氣體是多麼的爆炸性
The potent greenhouse gas methane, is bubbling out of the frozen Arctic much faster than expected and could stoke global warming.
強效的溫室氣體甲烷，汩汩地流出冰凍的北極比預期快得多，並可能引發全球變暖。
Methane had become trapped in the permafrost over time and now 8million tonnes of it is seeping out due to rising temperatures, researchers said today.
甲烷已長時間被困在凍土，但現在 800萬噸的沼氣由於氣溫升高正在滲出，研究人員今天說。
'Subsea permafrost is losing its ability to be an impermeable cap,' Natalia Shakhova, a scientist at the University of Fairbanks, Alaska, said in a statement.
'次海凍土正在失去它的能力作為一層防滲帽，'阿拉斯加費爾班克斯大學的一位科學家Shakhova在聲明中說。
She co-led the study published in today's edition of the journal Science.
'The amount of methane currently coming out of the East Siberian Arctic Shelf is comparable to the amount coming out of the entire world's oceans.'
However, she said noone knew whether the venting was caused by global warming or by natural factors.
Concerns about global warming have centered on rising levels of carbon dioxide in the atmosphere, but methane can be 30 times more effective at trapping heat than carbon dioxide.
Martin Heimann from the Max Planck Institute said it was good to document these emissions but that there is no proof they are increasing.
'These leaks could have been occurring all the time since the last Ice Age 10,000 years ago,' he said.
He added that the release of eight million tonnes of methane a year was "negligible" compared to global emissions of about 440 million tonnes.
About 60 percent of methane now comes from human activities such as landfills, cattle rearing or rice paddies. Natural sources such as wetlands make up the rest, along with poorly understood sources such as the oceans, wildfires or termites.
But Dr Shakhova said there was an 'urgent need' to monitor the region for possible future changes since permafrost traps vast amounts of methane, the second most common greenhouse gas from human activities after carbon dioxide.
The sea surface above the East Siberian Arctic Shelf is full of ice and bubbles. Sonar is used to detect the vast clouds of methane bubbles rising from the sea floor
東西伯利亞北極架的海面上充滿冰和泡沫，聲納被用去探測大量的從海底上升的甲烷泡沬雲
Historically, methane concentrations in the world's atmosphere have ranged between 0.3 and 0.4 parts per million in cool periods to 0.6 to 0.7 in warm periods.
Current methane concentrations in the Arctic average about 1.85 parts per million, the scientists said, the highest in 400,000 years.
The authors wrote that a release of just a 'small fraction of the methane held in (the) East Siberian Arctic Shelf sediments could trigger abrupt climate warming
http://www.dailymail.co.uk/sciencetech/article-1255652/Climate-change-Methane-escaping-Arctic-faster-expected-stoke-global-warming-warn-scientists.html
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