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
One fine day about 74 000 years ago, a giant volcano on Sumatra blew its top. The volcano, named Toba, may have ejected(喷射)1 000
One fine day about 74 000 years ago, a giant volcano on Sumatra blew its top. The volcano, named Toba, may have ejected(喷射)1 000
admin
2015-07-31
19
问题
One fine day about 74 000 years ago, a giant volcano on Sumatra blew its top. The volcano, named Toba, may have ejected(喷射)1 000 times more rock and other material than Mount St. Helens in Washington state did in 1980. In the process, it cooled the climate by at least 10°C, causing a global famine.
Paleoclimate(古气候)evidence suggests that the Toba eruption, which occurred during the last ice age, emitted lots of sulfur dioxide—vastly more than Mount St. Helens did. The eruption also seems to have coincided with the start of a 1 000-year period of even colder temperatures. Some scientists have suggested that Toba caused the deep freeze and that perhaps such an event happening today could bring on a new ice age. But models developed by National Aeronautics and Space Administration and the National Center for Atmospheric Research in Boulder, Colorado, argue otherwise.
Researchers led by climatologist Alan Robock of Rutgers University in New Brunswick, New Jersey, ran scenarios that featured eruptions producing up to several times more sulfur dioxide than Toba. The result, published 27 May in the Journal of Geophysical Research—Atmospheres, was a cooler climate that lasted only a few decades. So the 1 000-year cold spell was probably part of the natural cycle that has produced more than a dozen ice ages over the past couple of million years.
"The results virtually eliminate mega(非常大的)volcanic eruptions as one of the key drivers of global-scale glaciation," says climatologist Ellen Mosley-Thompson of Ohio State University in Columbus, who was not involved in the study. So, paleoclimatologists should focus on more likely climate coolers, she says, such as changes in ocean circulation or cyclical variations in Earth’s orbit around the sun.
Still, if Toba erupted today like it did in the past, the results would be catastrophic. Although the volcano isn’t expected to blow its top for thousands of years, Robock and colleagues estimate a megaeruption could lower global temperatures by as much as 17°C for several years, followed by a recovery to normal conditions that could take decades. That would hit the human population with the double whammy of dramatically reduced agricultural production and widespread loss of vegetation, leading to widespread food shortages and starvation.
What can be learned about the time of the Toba eruption?
选项
A、The eruption coincided with the end of the last ice age.
B、A new ice age triggered off Toba eruption.
C、The eruption occurred when the earth was at its coldest time.
D、The eruption happened when a 1 000-year period of colder temperatures began.
答案
D
解析
细节辨认题。由定位句可知,多巴火山的爆发时间也正是千年寒冷期的开端,因此D)正确。
转载请注明原文地址:https://kaotiyun.com/show/0rl7777K
0
大学英语四级
相关试题推荐
A、Kidswillneverplaywithfireagain.B、Kidswillbumthemselvesagainandagain.C、Peoplemaybecomemuchstronger.D、Humanb
Livinginatimewhenanever-increasingnumberofnewsproviderspushaconstantstreamofheadlinesatuseveryday,peopleca
Graduatingseniorsmayfacehigherriskforjobburnout(筋疲力尽,枯竭)thantheirparents’generation,saybusinessandcareerexperts.
Graduatingseniorsmayfacehigherriskforjobburnout(筋疲力尽,枯竭)thantheirparents’generation,saybusinessandcareerexperts.
Mothersreallydofavourtheir"preciousfirstboms"overthechildrentheyhavelater,researchhasfound.Amongexampleso
Readingisanimportantskillthatneedstobedevelopedinchildren.Notonlyisitnecessaryfor【C1】______intheworldofscho
SevenWaystoSavetheWorldA)Forgettheoldideathatconservingenergyisaformofself-denial—ridingbicycles,dimmingthe
SevenWaystoSavetheWorldA)Forgettheoldideathatconservingenergyisaformofself-denial—ridingbicycles,dimmingthe
SevenWaystoSavetheWorldA)Forgettheoldideathatconservingenergyisaformofself-denial—ridingbicycles,dimmingthe
随机试题
我国工会的性质及地位。
按照决策的性质不同,可以将决策分为()
男,25岁,反复右下腹痛、腹泻4年,无黏液脓血便,结肠镜检查发现右半结肠呈节段性炎症改变。该患者选做下列哪项检查最适宜
牙髓组织切片中见血管扩张、充血,慢性炎细胞浸润。其中见胶原纤维包绕一圆形组织坏死区,内充满死亡的中性粒细胞。此病变最可能是
铸造金属全冠面磨除的厚度至少为金属烤瓷冠的基底冠厚度至少为
不属于地役权与相邻权关系的内容范围的是()。
()是指银行经营的每条生产线内所包含的产品项目的数量。
某轧钢厂为生产一种市场上畅销的薄钢板,进行了试生产。生产此种薄钢板,需要块状、散装原材料甲,月需求量为300吨,单价为600元/吨,每单位原料年储存费用为该原料单价的12%,单次订货费用为100元。订货提前期为10天,每年的工作日为288天。根据以上材料,
Youngwomenwhotakepartinbeautycontests(比赛)arehelpingtokeepaliveanoutdatedo-pinionofwomen:thatawoman’smostim
A、He’llprobablytalkaboutChapter16inclasstoday.B、He’llprobablypostponethetestuntilhetalksaboutChapter16.C、He
最新回复
(
0
)