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
2011-01-05
49
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. 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
转载请注明原文地址:https://jikaoti.com/ti/lBLMFFFM
本试题收录于:
C类竞赛(非英语专业本科)题库大学生英语竞赛(NECCS)分类
0
C类竞赛(非英语专业本科)
大学生英语竞赛(NECCS)
相关试题推荐
(1)AmassiveearthquakestruckHaitijustbefore5p.m.onJan.12,about10milessouthwestofPort-au-Prince,thecountry’sc
(1)WhenpeoplehearthatI’mwritinganarticleaboutdeception,they’requicktotellmehowtocatchaliar.Liarsalwaysloo
Ifyouarearesident,you’llfinditusefultoopena【T1】________.Allthelargebankshaveanetworkof【T2】________acrossthe
Hello,everybody.Thankyouverymuchforinvitingmehere.It’sverypleasanttohaveachancetotalktoyouaboutsomethingt
Forshopaholics,thepost-Christmas【T1】________meansonlyonething—sales!Acrossthecountry,pricesareslashedon【T2】________
Theinternationalsituationhasbeengrowing________difficultforthelastfewyears.
Thecompanyannouncedthatithasachieveditsmissiontocreatealocalfoodeconomythatis________toanyenvironment.
Theoperationcould________herlifebytwoorthreeyears.
(1)NOTallthatMrs.Bennet,however,withtheassistanceofherfivedaughters,couldaskonthesubjectwassufficienttodra
A、Toshowitisimportanttohaveculturalbackground.B、Toshowthattheclothesdidn’tfitherdaughter.C、Toexpressherange
随机试题
超声造影的反射源是
下列不属于睡眠呼吸暂停综合征全身器官损害的表现的是
有机磷农药中毒的机制是
一男孩,5岁。发热39.5℃,咽喉肿痛,咳嗽,鼻塞流涕,头痛,面部和耳后有针头大小的丘疹,部分融合呈砖红色,或片状斑丘疹。诊断为麻疹初起,属风热外束肌表,宜选下列何组药物治疗
矩形基础A顶面作用着竖向力N与水平力H;基础B的尺寸及地质条件均与基础A相同,竖向力N与水平力H的数值和作用方向均与基础A相同,但竖向力N与水平力H都作用在基础B的底面处,比较两个基础的基底反力(平均值、最大值pmax及最小值pmin),下列选项中哪一个是
从功能角度分析,机器由哪几部分组成?各组成部分有何功用?
2011年,“量体裁衣”式个性化服务开始在某省全面推广。该省残联印发了《关于在全省全面推行为残疾人提供“量体裁衣”式个性化服务的实施方案”》“量体裁衣”包括人户调研、制定方案、组织实施和督促检查四个环节。人户调研指各乡镇(街道)、村(社区)要安排基层残疾人
下列关于进程的叙述中,哪些是正确的?()
IEEE在1980年2月成立了局域网标准化委员会(简称为IEEE802委员会),专门从事局域网的协议制定,形成了称为______的系统标准。
打开VisualFoxPro“项目管理器”的“文档”选项卡,其中包括()。
最新回复
(
0
)