5千亿吨史前有机物质可能大大加快“全球变暖”

读者: 1211    发布时间: 2007

原文: 500 Billion Tons of Prehistoric Organic Matter May Massively Accelerate ‘Global Warming’

Prehistoric_cave_art For thousands of years animal waste, and other organic matter left behind on the Arctic tundra, have been sealed off from the environment by permafrost. Now climate change is melting the permafrost and freeing mass quantities of prehistoric “ooze” from its state of suspended animation.

Russian scientist, Sergei Zimov, has been studying climate change in Russia's Arctic for 30 years now. He is worried that as this organic matter becomes exposed to the air it will drastically accelerate global warming predictions even beyond some of the most pessimistic forecasts.

"This will lead to a type of global warming which will be impossible to stop," he said.

According to Zimov, when the organic matter left behind by mammoths and other wildlife is exposed to the air by the thawing permafrost, microbes that have been dormant for thousands of years will spring back into action. They’ll begin once again to emit carbon dioxide and methane gas as a by-product. Zimov says thought the microbes are tiny, they will start emitting these gases in enormous quantities simply because there will be a lot of them.

Yakutia is a region in the north-eastern corner of Siberia, where a belt of permafrost contains the mammoth-era soil. It covers an area roughly the size of France and Germany combined. There is even more of it elsewhere in Siberia.

"The deposits of organic matter in these soils are so gigantic that they dwarf global oil reserves," Zimov said. U.S. government statistics show mankind emits about 7 billion tons of carbon a year."Permafrost areas hold 500 billion tons of carbon, which can fast turn into greenhouse gases," Zimov added. "If you don't stop emissions of greenhouse gases into the atmosphere ... the Kyoto Protocol (an international pact aimed at reducing greenhouse emissions) will seem like childish prattle."

While some dismiss the 52-year-old as an alarmist crank, his theory is steadily gaining credibility in the scientific community. "There's quite a bit of truth in it," Julian Murton, member of the International Permafrost Association, told Reuters. "The methane and carbon dioxide levels will increase as a result of permafrost degradation."

A United Nations report in June said there was at yet no sign of widespread melting of permafrost that could stoke global warming, but noted the potential threat. "Permafrost stores a lot of carbon, with upper permafrost layers estimated to contain more organic carbon than is currently contained in the atmosphere," the report said.

"Permafrost thawing results in the release of this carbon in the form of greenhouse gases which will have a positive feedback effect to global warming."

译文: 5千亿吨史前有机物质可能大大加快“全球变暖”

Prehistoric_cave_art 
千百年来,留在北极苔原的动物废弃物及其它有机物质被永久冻结带密封而与外部环境隔开了,现在,气候变化正在使永久性冻土融化,释放出大量的史前“软泥”,将它们从暂停活动中解放出来。

俄罗斯科学家谢尔盖兹莫夫30年来一直在研究俄罗斯北极地区的气候变化。他担心这些有机质暴露见光将大大加快全球变暖的预期,甚至超过那些最悲观的预测。

“如此引发的这一类型的全球变暖,将是不可能停止的,”他说。

兹莫夫说,猛犸和其他野生动物的遗留物由于冻土融化而暴露在空气中,使休眠了数千年的微生物复苏活跃起来。它们将再一次开始排出二氧化碳和甲烷等副产品。兹莫夫说,这些微生物虽然微小,它们数量将会很多;因此,他们将排放大量的温室气体。

雅库特位于西伯利亚的东北角,那里冻土层覆盖着猛犸时期的土壤。它涵盖的面积与法国加上德国的总和差不多大小。在西伯利亚的其它地方还有更多冻土盖着的猛犸土壤。

“土壤里有机质的贮量是如此巨大,它们让全球石油储备相形见绌,”兹莫夫说。美国政府的统计数字显示,人类排放约每年70亿吨碳。“冻土区持有5千亿吨碳,而且这些碳可以快速地转为温室气体,”兹莫夫补充道。“如果你不停止排放温室气体到大气中去...京都议定书(国际条约,旨在减少温室气体的排放量)将看起来是稚气侈谈。”

虽然有些人将这位52岁的人看作一位杞人忧天者,他的理论在科学界得到越来越多的认可。“这里面有相当多的真理,”国际冻土协会委员朱利安默顿告诉路透社记者。“由于冻土退化,甲烷和二氧化碳水平将会增加。”

联合国在6月的一份报告中表示,目前在还没有能引发全球变暖的大范围冻土融化的迹象。但他指出了潜在的威胁。“永久冻结带贮藏了许多碳,估计上层永久冻结带包含的有机碳比目前大气层中的要多,”报告说。

"
冻土层解冻导致碳以温室气体的形式释放,这肯定会对全球气候变暖产生作用。”