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Water一the Issue of This Century
The world is running short of freshwater. Populations are growing bigger and thirstier (渴的),with the result that freshwater is becoming increasingly scarce(缺乏).Half the world's wetlands have disappeared during the last century,while estimates suggest that wa- ter use will rise by 50% in the next 30 years.
The World Bank report estimates that as much as half of the world's population,concentrated in Africa,the Middle East and south Asia,will face“severe water shortages”by 2025.Local water conflicts and the loss of freshwater ecosystems appear large in some re- gions.
A similar picture emerges from the globe's salt water regions. Three-quarters of the world's people may live within 100km of the sea in 2025,putting even more pressure on stretched coastal ecosystems. Two thirds of fisheries(渔业)are exploited at or beyond their sustainable limits, and half the world's coral reefs(珊瑚礁)may perish in 100 years. Almost 60% of coral reefs and 34% of fish species are at risk from human activities,the Bank says.
The report concludes that there is ample evidence to justify immediate and coordinated action to safeguard supplies and use water more efficiently.
Fresh water consumption is rising quickly,and the availability of water in some regions is likely to become one of the most pressing issues of the 21st century.
A third of the world's popu1ation一around two billion people一live in countries that are experiencing moderate to high water shortages.That proportion could rise to half or more in the next 30 years unless institutions(制度)change to ensure better conservation and alloca- tion of water.
China is one country where the portents(征兆)are gloomy. The most waterstressed country in East Asia,China is exploiting 44%of its usable water,a figure projected to rise to6O%by 2020.Primary withdrawal of water of more than 60%is widely considered by water experts to exceed the environmental carrying capacity of a river basin system. Although
China's total use appears still to be reasonable,it has several basins that are severely stressed environmentally.
Withdrawals exceed environmental limits in Afghanistan and Pakistan,and will exceed them in India by 2020.In the Middle East and North Africa,only Morocco has unexploited water resources.The rest have exceeded environmental limits and many are mining aquifers (蓄水层)一bodies of water-bearing rock一the report says.
It is estimated that water use will rise by 50% in the next 30 years.
A: Right
B: Wrong
C: Not mentioned

相关标签: 珊瑚礁  

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A.限制大气温度上升至少会留给珊瑚礁一些时间去适应
B.全球气侯变暖致使近海珊瑚礁系统越来越缓慢地钙化
C.气温持续上升将会导致发生白化事件的间隔越来越长
D.气温升高压力导致浅水珊瑚要到更深的水域寻求庇护

当前,海水温度上升引发一系列白化事件,研究人员非常担心全球珊瑚的命运,研究人员发现,虫黄藻能够利用光合作用产生自己及其寄主所需的养分,当温度较高的海水导致班费上上排出名为由黄藻的共生藻类时,失去彩色藻类的那潮逐渐变为白色,白化现象便发生了。如果白化现象特续下去,等待珊瑚礁的便只有死亡。由此我们可以推出:

A.限制大气温度上升至少会给珊瑚礁一些时间去适应

B.全球气候侯变暖致使折近海珊瑚礁系统越来越慢的钙化

C.气温持续上升将会导致发生一白化事件的间隔越来越长

D.气温升高压力导致浅水珊瑚要到更深的水域寻求底护

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