#大學英語聽力#

Permafrost in Canada, Alaska and Siberia is abruptly crumbling in ways that could release large stores of greenhouse gases more quickly than anticipated, researchers have warned.

研究人員警告說，加拿大、阿拉斯加和西伯利亞的永久凍土正在突然崩塌，可能會以比預期更快的速度釋放大量的溫室氣體。

Scientists have long fretted that climate change - which has heated Arctic and subarctic regions at double the global rate - will release planet-warming CO2 and methane that has remained safely locked inside Earth's frozen landscapes for millennia.

長期以來，科學家們一直擔心，氣候變化-北極和亞北極地區的升溫速度是全球的兩倍-將釋放導致地球變暖的二氧化碳和甲烷，而這些二氧化碳和甲烷幾千年來一直安全地鎖在地球的冰凍景觀中。

It was assumed this process would be gradual, leaving humanity time to draw down carbon emissions enough to prevent permafrost thaw from tipping into a self-perpetuating vicious circle of ice melt and global warming.

人們認為這一過程將是漸進的，給人類留下足夠的時間來減少碳排放，以防止永久凍土融化陷入冰川融化和全球變暖的自我持續的惡性迴圈。

But a study published on Monday in Nature Geoscience says projections of how much carbon would be released by this kind of slow-and-steady thawing overlook a less well-known process whereby certain types of icy terrain disintegrate suddenly - sometimes within days.

但週一發表在“自然地球科學”(Nature Geoscience)上的一項研究稱，對這種緩慢而穩定的解凍會釋放多少碳的預測，忽略了一個不太為人所知的過程，即某些型別的冰雪地形突然解體-有時會在幾天內解體。

"Although abrupt permafrost thawing will occur in less than 20 percent of frozen land, it increases permafrost carbon release projections by about 50 percent," said lead author Merritt Turetsky, head of the Institute of Arctic and Alpine Research in Boulder, Colorado.

科羅拉多州博爾德市北極與阿爾卑斯山研究所所長梅里特·圖雷茨基(Merritt Turetsky)說：“雖然在不到20%的冰凍土地上會發生突然的永久凍土融化，但它將永久凍土碳釋放預測增加了約50%。”該研究所的主要作者梅里特·圖雷茨基(Merritt Turetsky)說。

"Under all future warming scenarios, abrupt thaw leads to net carbon losses into the atmosphere," she told AFP.

她告訴法新社：“在所有未來變暖的情況下，突然解凍會導致大氣中碳的淨損失。”

Permafrost contains rocks, soil, sand and pockets of pure ground ice.

永久凍土包含岩石、土壤、沙子和一片片純淨的地面冰。

Its rich carbon content is the remains of life that once flourished in the Arctic, including plants, animals and microbes.

其豐富的碳含量是曾經在北極繁衍生息的生命遺蹟，包括植物、動物和微生物。

This matter - which never fully decomposed - has been frozen for thousands of years.

這種從未完全分解的物質已經凍結了幾千年。

It stretches across an area nearly as big as Canada and the United States combined, and holds about 1,500 billion tonnes or carbon - twice as much as in the atmosphere and three times the amount humanity has emitted since the start of industrialisation.

它覆蓋的面積幾乎相當於加拿大和美國的總和，擁有大約1.5萬億噸或碳-是大氣中碳排放量的兩倍，是工業化開始以來人類排放量的三倍。