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
"Usually when we walk through the rain forest we hear a soft sound from all the moist leaves and organic debris on the forest fl
"Usually when we walk through the rain forest we hear a soft sound from all the moist leaves and organic debris on the forest fl
admin
2013-10-08
30
问题
"Usually when we walk through the rain forest we hear a soft sound from all the moist leaves and organic debris on the forest floor," says ecologist Daniel Nepstad. "Now we increasingly get rustle and crunch. That’s the sound of a dying forest. "
Predictions of the collapse of the tropical rain forests have been around for years. Yet until recently the worst forecasts were almost exclusively linked to direct human activity, such as clear-cutting and burning for pastures or farms. Left alone, it was assumed, the world’s rain forests would not only flourish but might even rescue us from disaster by absorbing the excess carbon dioxide and other planet-warming greenhouse gases. Now it turns out that may be wishful thinking. Some scientists believe that the rise in carbon levels means that the Amazon and other rain forests in Asia and Africa may go from being assets in the battle against rising temperatures to liabilities. Amazon plants, for instance, hold more than 100 billion metric tons of carbon, equal to 15 years of tailpipe and chimney emissions. If the collapse of the rain forests speeds up dramatically, it could eventually release 3.5-5 billion metric tons of carbon into the atmosphere each year—making forests the leading source of greenhouse gases.
Uncommonly severe droughts brought on by global climate changes have led to forest-eating wildfires from Australia to Indonesia, but nowhere more acutely than in the Amazon. Some experts say that the rain forest is already at the brink of collapse.
Extreme weather and reckless development are plotting against the rain forest in ways that scientists have never seen. Trees need more water as temperatures rise, but the prolonged droughts have robbed them of moisture, making whole forests easily cleared of trees and turned into farmland. The picture worsens with each round of El Nino, the unusually warm currents in the Pacific Ocean that drive up temperatures and invariably presage(预示)droughts and fires in the rain forest. Runaway fires pour even more carbon into the air, which increases temperatures, starting the whole vicious cycle all over again.
More than paradise lost, a perishing rain forest could trigger a domino effect—sending winds and rains kilometers off course and loading the skies with even greater levels of greenhouse gases—that will be felt far beyond the Amazon basin. In a sense, we are already getting a glimpse of what’s to come. Each burning season in the Amazon, fires deliberately set by frontier settlers and developers hurl up almost half a billion metric tons of carbon a year, placing Brazil among the top five contributors to greenhouse gases in the world.
The author argues that the rising carbon levels in rain forests may______.
选项
A、turn them into a major source of greenhouse gases
B、change the weather patterns throughout the world
C、pose a threat to wildlife
D、accelerate their collapse
答案
A
解析
事实细节题。文章第二段末句提到,如果热带雨林瓦解的速度显著加快,其最终每年向大气中释放35~50亿公吨的碳量,这会使森林成为温室气体的主要来源,故答案为A)。
转载请注明原文地址:https://jikaoti.com/ti/dB8FFFFM
0
大学英语六级
相关试题推荐
A、Howmanyweeksthereareinamonth.B、Whichdayspeopleshouldwork.C、Howtheweekisdividedintodays.D、Whichdaybegins
Thehorseandcarriageisathingofthepast,butloveandmarriagearestillwithusandstillcloselyinterrelated.MostAmer
Thehorseandcarriageisathingofthepast,butloveandmarriagearestillwithusandstillcloselyinterrelated.MostAmer
Thehorseandcarriageisathingofthepast,butloveandmarriagearestillwithusandstillcloselyinterrelated.MostAmer
Healthcostshavebeenrisingformiddleclassfamilies.NearlyoneinfiveAmericanscannotaffordhealthinsurance.(36)______
Healthcostshavebeenrisingformiddleclassfamilies.NearlyoneinfiveAmericanscannotaffordhealthinsurance.(36)______
Healthcostshavebeenrisingformiddleclassfamilies.NearlyoneinfiveAmericanscannotaffordhealthinsurance.(36)______
Throughmymom’slovingwords,Ifoundawayback.Whenyouwakeupinjail—especiallyhavingbeenraisedbyGod-fearing,h
A、Theywillcheckthetrafficlight.B、Theywillwaitforalittlelonger.C、TheywillcallNancy.D、Theywillcheckthetimeof
WheneverIhearaweatherreportdeclaringit’sthehottestJune10onrecordorwhatever,Ican’ttakeittooseriously,becaus
随机试题
下列情形中,应认定为入户抢劫的是
某步进电动机有48个齿,采用五相十拍方式运行,其步距角为【】
行政单位公用车辆燃料费,应记入支出的目级科目为()
手术人员下列操作不符合无菌原则的是()
刑法分则各条规定的是:
在自营账户的审核和稽核制度中,以下不属于禁止行为的是()。
某企业为一般纳税人,增值税税率为17%,2013年7月发生下列业务:(1)购买材料一批,专用发票注明:价款300万元,增值税17万元,另外支付运费1万元,已入库,并付款;(2)销售产品一批,专用发票注明:价款500万元,增值税85万
下列历史名人中,属于古徽州的有()。
从科学史看,理论再伟大,也只有在特定的范围内才是正确的。标准模型虽然即将被证实,但其依然位于微观世界,无法解释宏观世界中的万有引力。《新科学家》撰文写道:“希格斯玻色子(也称为‘上帝粒子’)是标准模型的最后一块拼图,但我们知道,这个模型之外,还有其他的粒子
若一个进程由于申请的内存资源长期不能得到满足,那么,操作系统处理该进程的最佳方法是()。
最新回复
(
0
)