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
Scientists say there has been a severe decrease in the amount of water in Lake Chad in northern Africa in the last thirty years.
Scientists say there has been a severe decrease in the amount of water in Lake Chad in northern Africa in the last thirty years.
admin
2007-01-12
73
问题
Scientists say there has been a severe decrease in the amount of water in Lake Chad in northern Africa in the last thirty years. They reported that nature and humans share equal blame for this loss.
In 1963, the fresh-water lake covered 25, 000 square kilometers. Now the lake is only about five percent of that size. It measures only about 1, 300 square kilometers in the dry season.
Four nations surround Lake Chad. People in Niger, Nigeria, Chad, and Cameroon use it for water, fish and plant life.
Michael Coe and Jonathan Foley, water experts at the University of Wisconsin in Madison, reported on Lake Chad in a science journal. They say the area has suffered from a lack of heavy rain for more than thirty years. This has forced people to build systems to carry water to dry land. These irrigation systems further decrease the amount of lake water.
Mr. Coe says Lake Chad will be only a small body of water in the future. He says people still can get water from the lake to drink and for crops. But he says the lake will no longer provide a healthy environment for fish and plant life.
The researchers used a computer to study what caused the water loss. Their computer study estimated the climate and amount of water in the area. The estimate started with written records from the early 1960s. Then the researchers compared the estimates with the area’s recorded climate and water supply for the same period.
The computer study showed results similar to the recorded ones for the first twenty years. But there was a big change in the 1980s. At the time, the lake got smaller much faster than the computer research had estimated.
The researchers say that major irrigation systems were built in the 1980s. The systems took water from two rivers that flow into Lake Chad. The Chari and Logone rivers carry most of the water that enters the lake. The study showed that the increased irrigation reduced the flow in the two rivers. Climate changes also were responsible for the reduction. The flow of the two rivers was reduced by almost seventy-five percent.
Scientists say the problem is expected to worsen in the coming years as the population and demand for water continued to increase.
When did the scientists find that Lake Chad got smaller much faster?
选项
答案
In the 1980s
解析
(文章倒数第三段指出The computer study showed results similar to the recorded ones for the first twenty years.But there was a big change in the 1980s.“此次利用计算机进行研究的结果与二十年前第一次记录的结果相似,但是有一个很大的变化。”因而可知第一次对乍得湖进行研究的时间是19世纪80年代。)
转载请注明原文地址:https://kaotiyun.com/show/yukK777K
本试题收录于:
D类竞赛(专科)题库大学生英语竞赛(NECCS)分类
0
D类竞赛(专科)
大学生英语竞赛(NECCS)
相关试题推荐
Thereisanunquestionablelinkbetweenjoblossesand______services.
Susandecidednottowriteherresignationintheofficebecauseshedidn’twanthercolleaguestoknowwhatshe______.
Whichofthefollowingitalicizedpartsisasubjectclause(主语从句)?
A.exploreB.distinctC.artisticD.inaccessibleE.subjectiveF.highlyG.factualH.declineI.definitivelyJ.currents
A.exploreB.distinctC.artisticD.inaccessibleE.subjectiveF.highlyG.factualH.declineI.definitivelyJ.currents
Shouldyoungpeoplecontinuetolivewiththeirparentsafterfindingajob?Thisissuehasbeenintenselydiscussedforyears.
Morethanfive-thousandsecondaryschoolstudentshavebeen______forcheating.
PASSAGEONEWhatcan"theconceptofartimposedbythetriumphofModernism"(Para2)bebestdescribedas?
WhichjobdidJaneWestmacottdescribeindetailonherCV?
WhatisJaneWestmacott’spostcode?
随机试题
公司股利发放的决定机构是
恶性葡萄胎与葡萄胎的主要区别是
在计算家畜寄生虫感染强度时,常用麦克马斯特法。计数时,若取2g粪便,加入了饱和食盐水58ml,那么计数后,每克粪便中的虫卵数应该是计数的平均值乘以下列的哪个数
违背了不伤害原则的做法是()
资产评估的市场属性主要体现在()。
甲公司2015年1月1日发行三年期可转换公司债券,实际收到发行价款11000万元。该债券的面值总额为10000万元,每年12月31日付息,到期一次还本。债券的票面年利率为4%,发行时二级市场与之类似的没有附带转换权的债券市场利率为6%。该可转换公司债券在发
某化学教师在一次测验中设计了下列测试题,并对学生的解题结果进行了统计和分析。【试题】下列关于溶液的说法中,正确的是()。A.相同质量的同一溶质的饱和溶液一定比它的不饱和溶液所含的溶质多B.在一定温度下,M物质的饱和溶液不能再溶解任何物质C.某一
为了解某地人民对建设创新社会的认识情况,当地知识产权局发放了调查问卷。问卷回收后发现,60%的被调查者对建设创新社会的意义有正确的认识,30%的被调查者能理解国家对创新社会的建设所作的投入。该地知识产权局由此得出结论,目前当地人民对于建设创新社会是能够认识
Jackson方法是一种面向______的结构化方法。
Agreeabletoyourrequest,IsendyoumyreasonsforthinkingthatournortheaststormsinNorthAmericabeginfirst,inpointo
最新回复
(
0
)