首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Dr Corell heads a team of some 300 scientists who have spent the past four years investigating the matter in a process known as
Dr Corell heads a team of some 300 scientists who have spent the past four years investigating the matter in a process known as
admin
2013-06-12
71
问题
Dr Corell heads a team of some 300 scientists who have spent the past four years investigating the matter in a process known as the Arctic Climate Impact Assessment (ACIA). The group, drawn from the eight countries with territories inside the Arctic Circle, has just issued a report called "Impacts of a Warming Arctic", a lengthy summary of the principal scientific findings.
Scientists have long suspected that several factors lead to greater temperature swings at the poles than elsewhere on the planet. One is albedo (反照率)-the posh scientific name for how much sunlight is reflected by a planet’s surface, and how much is reflected. Most of the polar regions are covered in snow and ice, which are much more reflective than soil or ocean. If that snow melts, the exposure of dark earth (which absorbs heat) acts as a feedback loop that accelerates warming. A second factor that makes the poles special is that the atmosphere is thinner there than at the equator, and so less energy is required to warm it up. A third factor is that less solar energy is lost in evaporation at the frigid poles than in the steamy tropics.
Arctic warming may influence the global climate in several ways. One is that huge amounts of methane, a particularly potent greenhouse gas, are stored in the permafrost of the tundra. Although a thaw would allow forests to invade the tundra, which would tend to ameliorate any global warming that is going on (since trees capture carbon dioxide, the greenhouse gas most talked about in the context of climate change), a melting of the permafrost might also lead to a lot of trapped methane being released into the atmosphere, more than offsetting the cooling effects of the new forests.
Another worry is that Arctic warming will influence ocean circulation in ways that are not fully understood. One link in the chain is the salinity of sea water, which is decreasing in the north Atlantic thanks to an increase in glacial meltwaters. Because fresh water and salt water have different densities, this "freshening" of the ocean could change circulation patterns. The most celebrated risk is to the mid-Atlantic Conveyor Belt, a current which brings warm water from the tropics to north-western Europe, and which is responsible for that region’s unusually mild winters. Some of the ACIA’s experts are fretting over evidence of reduced density and salinity in waters near the Arctic that could adversely affect this current.
The biggest popular worry, though, is that melting Arctic ice could lead to a dramatic rise in sea level. Here, a few caveats are needed. For a start, much of the ice in the Arctic is floating in the sea already. Archimedes’s principle shows that the melting of this ice will make no immediate difference to the sea’s level, although it would change its albedo. Second, if land ice, such as that covering Greenland, does melt in large quantities, the process will take centuries. And third, although the experts are indeed worried that global warming might cause the oceans to rise, the main way they believe this will happen is by thermal expansion of the water itself.
Nevertheless, there is some cause for nervousness. As the ACIA researchers document, there are signs that the massive Greenland ice sheet might be melting more rapidly than was thought a few years ago. Cracks in the sheet appear to be allowing melt water to trickle to its base, explains Michael Oppenheimer, a climatologist at Princeton University who was not one of the report’s authors. That water may act as a lubricant, speeding up the sheet’s movement into the sea. If the entire sheet melted, the sea might rise by 6-7 metres. While acknowledging that disintegration this century is still an unlikely outcome, Dr Oppenheimer argues that the evidence of the past few years suggests it is more likely to happen over the next few centuries if the world does not reduce emissions of greenhouse gases. He worries that an accelerating Arctic warming trend may yet push the ice melt beyond an "irreversible on/off switch".
Not everybody wants to hear a story like that. But what people truly believe is happening can be seen in their actions better than in their words. One of the report’s most confident predictions is that the break-up of Arctic ice will open the region to long-distance shipping and, ironically, to drilling for oil and gas. It is surely no coincidence, then, that the Danish government, which controls Greenland, has just declared its intention to claim the mineral rights under the North Pole. It, at least, clearly believes that the Arctic ocean may soon be ice-free.
The passage can best be found in ______.
选项
A、an encyclopedia
B、science fiction
C、a magazine
D、a dissertation
答案
C
解析
本篇文章最有可能出现在哪里?本文节选自《经济学家》上一篇文章,文章的主要内容是介绍ACIA专家们的最新研究报告。
转载请注明原文地址:https://kaotiyun.com/show/sw4O777K
0
专业英语八级
相关试题推荐
Argumentation:FunctionsandStrategiesⅠ.Functionsofargumentation:Youcanuseargumentationto1)makeapoint
Therearesuperstitionsattachedtonumbers;eventhoseancientGreeksbelievedthatallnumbersandtheirmultiplehavesomemy
WhichisthecorrectinformationabouttheBest361CollegessurveycarriedoutbythePrincetonReview?
Insixteenth-centuryItalyandeighteenth-centuryFrance,waningprosperityandincreasingsocialunrestledtherulingfamilies
由小学到中学,所修习的无非是一些普通的基本知识。就是大学四年,所授课业也还是相当粗浅的学识。世人常称大学为“最高学府”,这名称易滋误解,好像过此以上即无学问可言。大学的研究所才是初步研究学问的所在,在这里作学问也只能算是粗涉藩篱,注重的是研究学问的方法和实
WhenIfirstreadthislinebyEngland’sPoetLaureate,itstartledme.WhatdidMasefieldmean?Withoutthinkingaboutitmuch,
Bynow,itshouldcomeasnosurprisewhenscientistsdiscoveryetanothercaseofexperiencechangingthebrain.Fromthesenso
Thesemanticrelationofroseandfloweriscalled
Thesealaylikeanunbrokenmirrorallaroundthepine-girt,lonelyshoresofOrr’sIsland.Tall,kinglysprucesworetheirr
中国是一个地域辽阔、有着数千年悠久历史的多民族国家,有着秀丽的自然风光、众多的名胜古迹和丰富多彩的灿烂文化,旅游资源十分丰富。改革开放以来,中国经济以年平均近10%的速度持续增长,各项事业蓬勃发展,人民生活水平显著提高,为旅游业的兴旺奠定了坚实的基础。中国
随机试题
印戒细胞型前列腺腺癌
润汤丸适宜于治疗()(2009年第59题)
结构与甲状腺激素类似,可影响甲状腺激素代谢的是
下列级数发散的是()
自然环境中影响生物有机体生命活动的一切因子是
气机的含义为
当心理咨询员不表明自己的态度会谈就无法进行时,心理咨询员也应当()。(2003年12月三级真题)
知识可分为陈述性知识和程序性知识,陈述性知识也可以称为记忆性知识,是一种狭义的知识;广义的知识应当包括程序性知识。()
HowAdvertisementIsDone?A)Whenwechooseawordwedomorethangiveinformation;wealsoexpressourfeelingsaboutwha
Menaremuch"smarter"thanwomenwhenitcomestoshopping,accordingtoasurveyof1,000peoplewhichfoundthat42%ofmen
最新回复
(
0
)