【双语阅读】北冰洋夏季的冰正在迅速消失.

　　为帮助广大考生更好地准备雅思、托福、SAT等考试，澳际留学特推出【英语学习】频道，涵盖基础英语、实用英语、娱乐英语等多项内容，在您通往成功的道路上做您最坚实的左膀右臂。

　　以下部分为【双语阅读】内容，中文翻译部分见第二页。

　　Now you don’t

　　Summer ice in the Arctic Ocean is vanishing rapidly

　　Sep 22nd 2012 | from the print edition

　　IN 2007 climate scientists were shocked when the regular summer retreat of the Arctic’s sea ice went far farther than they had ever seen bore. In the spring of that year ice covered just under 15m km2 (5.8m square miles) of ocean—an area 90% as big as Russia. By mid-September, when it reached its minimum, there were just 4.17m km2 lt. That is about the area of the European Union minus Greece. Since 1979, when satellites made such measurements possible, there had been no melt like it.

　　Until now. Though the extent of the September sea ice did bounce back a little from 2007’s nadir, in every year since then the minimum has been lower than it was in every year bore 2007. And this year 2007’s record has not been merely broken, it has been smashed. Coverage fell below 4.17m km2 as early as August 26th. By September 16th, which America’s National Snow and Ice Data Centre (NSIDC) thinks marked the low point, it was down to 3.41m km2 (see map). That is the European Union minus Greece, Portugal, Ireland, Britain and Germany.

　　This is all the more surprising because 2012 has in other ways been a pretty ordinary year in the Arctic. In 2007 the summer weather was particularly inimical to the persistence of ice, with lots of warm southerly winds and clear skies that allowed the sunshine to do its worst. This year has seen far less in the way of special circumstances. It is true that a powerful cyclone chewed up a lot of ice in the East Siberian and Chukchi seas in early August—but the rate of ice loss outstripped that seen in 2007 both bore the storm and after it.

　　The summer sea ice is shrinking so much mostly because greenhouse warming is raising Arctic temperatures. This has direct fects: when the air is warmer, more ice melts. It also has indirect fects. Warm, salty water from the North Atlantic sliding below the cold, fresh upper layers of the Barents Sea may be one of them. Another could be that warmer air is often moister. Moist air traps more heat in summer. In winter it tends to create more clouds, which keeps the surface below warm.

　　Disappearing trick

　　In theory, climate models should help tease out which of these indirect fects is playing the biggest role, and also say how much of the decline in ice cover can be assigned to natural variability and how much to feedback loops in which a little warming leads to a lot more. The most famous of these feedbacks is the ice-albedo fect: the darker (“lower-albedo”) surfaces revealed when bright, rlective ice melts go on to absorb more sun than the ice did, accelerating the process that originally provoked the melting.

　　Unfortunately, climate models do not seem to be good at coping with the Arctic. The melt is happening much faster in reality than it does in computer programs. It seems these are not capturing the subtleties of the ways in which more heat is getting to the far north, and that these subtleties matter.

　　This makes it hard to say how fast the summer ice cover will continue to shrink. But the betting has to be that it will indeed continue to do so. The warming trend means that, every year, there is less old ice and more new ice that has formed in the winter just past. That new ice will often be fragile and thin, easily disrupted by summer weather. And in a warmer world the sort of cold conditions that used to allow the ice to thicken and reinforce itself are that bit less common, so opportunities to reverse the trend are rare.

　　It is still possible that changes in wind patterns and longer-term natural climate shifts may slow the currently tumultuous process of decline. But according to Mark Serreze of NSIDC the system has entered a “new regime” in which, eventually, most of the ice will come and go every year, with little lasting the whole summer. September ice cover of less than 1m km2 could be normal within decades. That’s just France and Germany.

　　A world in which sunshine and ocean currents push a lot more energy into the Arctic in the summer will be one where much of that energy comes back out in the winter, as the surface waters cool and the ice freezes back. This release of heat will probably change the atmosphere’s circulation patterns, perhaps through the jet stream, a wind which circles the world in the lower stratosphere, perhaps through other means. Such changes will, in turn, affect the weather at lower latitudes.

　　Various groups of researchers have sought to link the expanses of open water north of Siberia in years with strong summer melting to cold subsequent winters in western Europe. More generally it has been suggested that the fect on the jet stream might increase the frequency of “blocking” patterns, in which weather conditions that would normally be expected to stay over a given region for only a few days get stuck for weeks or months, provoking droughts and heatwaves.

　　Over and out?

　　As yet none of these ideas has been confirmed, and for now there is no dinitely discernible pattern in terms of severe weather. James Overland of America’s National Oceanic and Atmospheric Administration, who works on the matter, points out that normally temperate places saw unusually cold winters in 2009-10 and 2010-11, which some people have linked to strong previous melting; but after similar melting the winters of 2011-12 and 2008-09 turned out quite differently.

　　The fects in the Arctic, on fisheries and trade, may be easier to measure. But low levels of ice do not mean open water everywhere. Shell’s attempts to drill for oil in the Chukchi Sea this August were forestalled by ice floes which, though small by the scale of continents, were pretty large by the standards of human engineering. On the other side of the ocean the Parry Channel, a part of the Northwest Passage which has been ice-free in previous years, this year stayed resolutely impassable.

　　Such quirks will make the Arctic an unpredictable place to work. But if the details are tricky, the big picture is clear. Clear as an open ocean.

　　from the print edition | Science and technology

　　【中文翻译对照】

　　现在，你不能这样做!

　　北冰洋夏季的冰正在迅速消失

　　2012年9月22日 | 来源于印刷版

　　早在2007年，气候科学家们就已对夏季北极的海冰撤退范围远远超出他们之前所见而感到震惊。在俄罗斯的春天，冰雪覆盖的海洋面积的90%不到15M平方公里(5.8米平方英里)。9月中旬，当它达到最低值时只有4.17米平方公里左。这是欧洲联盟的面积减去希腊的。自1979年以来，在卫星这样的测量下没有融像成为可能。

　　截止到现在，虽然9月海冰的程度也从2007年的最低点反弹了一点，但每年自那时以来，最低面积低于它也是在2007年之前每年。而早在今年8月26日覆盖跌破4.17米平方公里的记录已经被瓦解。 9月16日，美国国家冰雪数据中心(NSIDC)认为标志已着最低点，这3.41米平方公里(查看地图) 是欧盟减去希腊，葡萄牙，爱尔兰，英国和德国的面积。

　　这更令我们吃惊，因为2012年它在北极已经是以其他方式成为非常平凡的一年。在2007年夏天的天气特别不利于持久的冰冻时，有很多的温暖的偏南风和晴朗的天空，导致了做出阳光下最坏准备的情况。而今年以来，情况远不如在特殊情况下的表现。这是一个强大的旋风吃掉大量的冰年初在东西伯利亚和楚科奇海的八月，但冰的损失率超过了在2007年在风暴之前和之后的。

　　夏季海冰正在萎缩如此多的主要是因为温室变暖是提高北极的温度。这直接导致了当空气温暖的后更多的冰悔融化。同时也会间接影响到温暖、盐水从北大西洋滑动，低于冷的空气上层的巴伦支海可能是其中之一。然而还存在着另一个可能，温暖的空气通常是潮湿的，潮湿的空气陷阱更多的热量在夏天。所以在冬天，它就会创建更多的云，这样会使表面下面温暖。

　　消失的把戏

　　理论上,气候模型应该能够帮助我们找出哪一种是发挥着最大间接影响作用的,还有多少冰盖的下降可以分配给自然可变性,多少反馈循环会导致更多的变暖。其中最著名的是冰反射反馈效应：深色(“低反照率”)表面显示应当明亮,而反射冰的融化会导致继续吸收更多的太阳冰,从而加速这个过程引发了融化。

　　不幸的是,气候模型似乎不太擅长“应付”北极，现实中的融化比它在计算机程序里更快。看来这些以及细节问题都不是捕捉更多的热量越来越到遥远的北方的方法。

　　这使得如何快速夏季冰盖将继续萎缩很难说。但我们可以打赌,它确实会继续这样发展。全球变暖的趋势意味着,每年将有更少的老冰和更多的新冰碛在冬天就过去。新冰常常会很脆弱和单薄,很容易被夏天的天气干扰。在一个更暖和的世界的那种寒冷条件下,用于允许冰增厚、加强本身是不太常见的,所以机会来扭转这一趋势是罕见的。

　　这种可能性是仍然存在的,风向模式的改变和长期的自然气候变化可能会减缓当前动荡过程的下降。但据Mark Serreze NSIDC的系统已经进入了一个“新政权”，最终大多数的冰会来来去去,每年几乎都持续整个夏天。 9月冰层覆盖不到平方公里可能在几十年内正常。这就是法国和德国的情况。

　　在阳光和洋流把更多的精力投入到北极世界里，夏天将有一大部分能量回到冬天,随着表面水体和冰冻结回来。释放热量通过急流,风环行世界平流层,也许通过其他手段将可能改变大气环流的模式。这些改变将会反过来影响天气在低纬度地区。

　　各种组织的研究人员试图在北西伯利亚随后在西欧，使其与强大的夏季融化后寒冷的冬天连接广阔开放的水。曾有研究表明,影响射流的频率可能会增加“阻塞”模式,在这种天气条件,正常预期保持在一个给定的地区只有几天几周或数月,从而引发干旱和热浪。

　　过去，还是出路?

　　迄今为止这些想法都已经确认,目前没有出现绝对明显的模式方面的恶劣天气。James Overland在美国国家海洋和大气管理局工作,他对这个问题指出,通常温带地区一些人已经在2009 - 10和2010 - 11看到异常寒冷的冬时已经融化;但是在强大的冬天融化的类似2011 - 2008年度和- 09年的结果则完全不同。

　　整个情况对北极、渔业和贸易的影响可能更容易衡量。但低水平的冰并不意味着到处都是水。壳牌今年8月试图在楚科奇海钻油被浮冰阻断了,虽然在人体工程学的标准下规模小仅相当大陆,但在太平洋的另一边帕里频道的一部分,西北航道前几年已无冰,所以今年坚决无法通行。

　　这种奇怪的现象会使得北极成为不可预测的工作场所。但如果细节是棘手的，大蓝图是清晰的，它将被明确作为一个开放的海洋。

　　印刷版 | 科学和技术

　　为帮助广大考生更好地准备雅思、托福、SAT等考试，澳际留学特推出【英语学习】频道，涵盖基础英语、实用英语、娱乐英语等多项内容，在您通往成功的道路上做您最坚实的左膀右臂。

　　以下部分为【双语阅读】内容，中文翻译部分见第二页。

　　Now you don’t

　　Summer ice in the Arctic Ocean is vanishing rapidly

　　Sep 22nd 2012 | from the print edition

　　IN 2007 climate scientists were shocked when the regular summer retreat of the Arctic’s sea ice went far farther than they had ever seen bore. In the spring of that year ice covered just under 15m km2 (5.8m square miles) of ocean—an area 90% as big as Russia. By mid-September, when it reached its minimum, there were just 4.17m km2 lt. That is about the area of the European Union minus Greece. Since 1979, when satellites made such measurements possible, there had been no melt like it.

　　Until now. Though the extent of the September sea ice did bounce back a little from 2007’s nadir, in every year since then the minimum has been lower than it was in every year bore 2007. And this year 2007’s record has not been merely broken, it has been smashed. Coverage fell below 4.17m km2 as early as August 26th. By September 16th, which America’s National Snow and Ice Data Centre (NSIDC) thinks marked the low point, it was down to 3.41m km2 (see map). That is the European Union minus Greece, Portugal, Ireland, Britain and Germany.

　　This is all the more surprising because 2012 has in other ways been a pretty ordinary year in the Arctic. In 2007 the summer weather was particularly inimical to the persistence of ice, with lots of warm southerly winds and clear skies that allowed the sunshine to do its worst. This year has seen far less in the way of special circumstances. It is true that a powerful cyclone chewed up a lot of ice in the East Siberian and Chukchi seas in early August—but the rate of ice loss outstripped that seen in 2007 both bore the storm and after it.

　　The summer sea ice is shrinking so much mostly because greenhouse warming is raising Arctic temperatures. This has direct fects: when the air is warmer, more ice melts. It also has indirect fects. Warm, salty water from the North Atlantic sliding below the cold, fresh upper layers of the Barents Sea may be one of them. Another could be that warmer air is often moister. Moist air traps more heat in summer. In winter it tends to create more clouds, which keeps the surface below warm.

　　Disappearing trick

　　In theory, climate models should help tease out which of these indirect fects is playing the biggest role, and also say how much of the decline in ice cover can be assigned to natural variability and how much to feedback loops in which a little warming leads to a lot more. The most famous of these feedbacks is the ice-albedo fect: the darker (“lower-albedo”) surfaces revealed when bright, rlective ice melts go on to absorb more sun than the ice did, accelerating the process that originally provoked the melting.

　　Unfortunately, climate models do not seem to be good at coping with the Arctic. The melt is happening much faster in reality than it does in computer programs. It seems these are not capturing the subtleties of the ways in which more heat is getting to the far north, and that these subtleties matter.

　　This makes it hard to say how fast the summer ice cover will continue to shrink. But the betting has to be that it will indeed continue to do so. The warming trend means that, every year, there is less old ice and more new ice that has formed in the winter just past. That new ice will often be fragile and thin, easily disrupted by summer weather. And in a warmer world the sort of cold conditions that used to allow the ice to thicken and reinforce itself are that bit less common, so opportunities to reverse the trend are rare.

　　It is still possible that changes in wind patterns and longer-term natural climate shifts may slow the currently tumultuous process of decline. But according to Mark Serreze of NSIDC the system has entered a “new regime” in which, eventually, most of the ice will come and go every year, with little lasting the whole summer. September ice cover of less than 1m km2 could be normal within decades. That’s just France and Germany.

　　A world in which sunshine and ocean currents push a lot more energy into the Arctic in the summer will be one where much of that energy comes back out in the winter, as the surface waters cool and the ice freezes back. This release of heat will probably change the atmosphere’s circulation patterns, perhaps through the jet stream, a wind which circles the world in the lower stratosphere, perhaps through other means. Such changes will, in turn, affect the weather at lower latitudes.

　　Various groups of researchers have sought to link the expanses of open water north of Siberia in years with strong summer melting to cold subsequent winters in western Europe. More generally it has been suggested that the fect on the jet stream might increase the frequency of “blocking” patterns, in which weather conditions that would normally be expected to stay over a given region for only a few days get stuck for weeks or months, provoking droughts and heatwaves.

　　Over and out?

　　As yet none of these ideas has been confirmed, and for now there is no dinitely discernible pattern in terms of severe weather. James Overland of America’s National Oceanic and Atmospheric Administration, who works on the matter, points out that normally temperate places saw unusually cold winters in 2009-10 and 2010-11, which some people have linked to strong previous melting; but after similar melting the winters of 2011-12 and 2008-09 turned out quite differently.

　　The fects in the Arctic, on fisheries and trade, may be easier to measure. But low levels of ice do not mean open water everywhere. Shell’s attempts to drill for oil in the Chukchi Sea this August were forestalled by ice floes which, though small by the scale of continents, were pretty large by the standards of human engineering. On the other side of the ocean the Parry Channel, a part of the Northwest Passage which has been ice-free in previous years, this year stayed resolutely impassable.

　　Such quirks will make the Arctic an unpredictable place to work. But if the details are tricky, the big picture is clear. Clear as an open ocean.

　　from the print edition | Science and technology

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