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本文选自《经济学人》8月15日刊文章。又到一年一度的炎热夏季，不仅人类在遭受热浪侵袭，南北极的冰架也深受气候变暖的影响，融化或断裂。受温度上升的影响，加拿大最后一块完整冰架再次断裂，成为四处漂流的冰块。随着冰架的消失，依赖它的生态系统也会随之消失，生活在那里的生物也会消亡。 
选文精讲 A shortened shelf life 缩短的冰架生命期Canada’s last intact ice shelf breaks upThe fate of a rare “epishelf lake” is unknownTHE LAST whole ice shelf in Canada’s Arctic was no match for this summer’s heatwave. In northern Ellesmere Island temperatures since May have been 5⁰C warmer than the 30-year average of 0-1⁰C. On July 30th-31st, the 80-metre (260-foot) thick Milne ice shelf, which juts out from the island’s north-western coast, split in two. A slab measuring 80 square km (31 square miles), more than 40% of the shelf’s surface area, broke away. By August 3rd the wandering wedge of ice split again. The two strays will now drift on the Beaufort Gyre current as they melt away (see map).加拿大北极的最后一块冰架根本无法抵挡今年夏天的热浪。从5月份开始，埃尔斯米尔岛北部的气温比30年来的平均温度0-1⁰C高出5⁰C。7月30日至31日，从该岛西北海岸突出出来的厚80米(260英尺)的米尔恩冰架裂开了，一块80平方公里(31平方英里)的冰块断开了，断开的部分超过冰架表面面积的40%。到了8月3日，漂流的冰块再次裂开。这两块漂流的冰块会随着波弗特环流融化而漂移(见地图)。A century ago Ellesmere’s northern coast had one 8,600 square km shelf, a floating island of ice driven onto shore some 4,000 years ago. During the 20th century it broke apart. The Milne shelf is the biggest remaining constituent. Derek Mueller, a geography professor at Carleton University in Ottawa who began documenting the ice shelves’ erosion in 2005, has seen the smaller ones collapse. Until now the Milne shelf had been protected by the high walls of the narrow 30km fjord along which it stretches.一个世纪前，埃尔斯米尔的北部海岸有一个8600平方公里的冰架，这是一个大约4000年前被冲上岸的浮冰岛。在20世纪，它分裂了，米尔恩冰架是裂开后的最大部分。渥太华卡尔顿大学的地理学教授德里克·穆勒从2005年开始记录冰架受侵蚀的情况，他目睹了较小冰架的崩塌。在此之前，米尔恩冰架一直被延伸30公里的狭长峡湾的高墙保护着。The breakaway block, a frozen chunk of the Arctic Ocean, will not itself raise sea levels. But the shelf’s disappearance would remove a stopper that prevents melting glacial water from seeping into the ocean, notes Luke Copland, a glaciologist at the University of Ottawa.分离出来的冰块是北冰洋的一块冰块，它本身不会使海平面上升。但是，渥太华大学的冰河学家卢克·科普兰指出，冰架的消失会让融化的冰川水失去屏障，直接流入海洋。
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