The Effects of Global Warming on Weather

　　There are hidden factors which scientists call "feedback mechanisms”。 No one knows quite how they will interact with the changing climate.Here's one example： plants and animals adapt to climate change over centuries.At the current estimate of half a degree centigrade of warming per decade,vegetation (植物) may not keep up.Climatologist James Hansen predicts climate zones will shift toward the poles by 50 to 75 kilometres a year—faster than trees can naturally migrate.Species that find themselves in an unfamiliar environment will die.The 1000-kilometer-wide strip of forest running through Canada,the USSR and Scandinavia could be cut by half.Millions of dying trees would soon lead to massive forest fires,releasing tons of CO2 and further boosting global warming.

　　There are dozens of other possible "feedback mechanism”。 Higher temperatures will fuel condensation and increase cloudiness,which may actually damp down global warming.Others,like the "albedo"effect,will do the opposite.The "albedo"effect is the amount of solar energy reflected by the earth's surface.As northern ice and snow melts and the darker sea and land pokes (戳) through,more heat will be absorbed,adding to the global temperature increase.

　　Even if we were to magically stop all greenhouse-gas emissions tomorrow the impact on global climate would continue for decades.Delay will simply make the problem worse.The fact is that some of us are doing quite well the way things are.In developed world prosperity has been built on 150 years of cheap fossil fuels.

　　Material progress has been linked to energy consumption.Today 75 percent of all the world's energy is consumed by a quarter of the world's population.The average rich-world resident adds about 3.2 tons of CO2 yearly to the atmosphere,more than four times the level added by each Third World citizen.The US,with just seven per cent of the global population,is responsible for 22 per cent of global warming.

　    41."Feedback mechanisms"in paragraph 1 most probably refer to ____________.

　　A.how plants and animals adapt to hidden factors

　　B.how plants and animals interact with the changing climate

　　C.how climate changes

　　D.how climate zones shift

　　42.We can learn from the passage that ____________.

　　A.some feedback mechanisms may slow down global warming

　　B.the basic facts of global warming are unknown

　　C.developing countries benefit from cheap fossil fuels

　　D.developed countries have decided to reduce their energy consumption

　　43.James Hansen predicts that the shift of climate zones will be accompanied by ____________.

　　A.the cutting of many trees

　　B.desirable environmental changes

　　C.successful migration of species

　　D.unsuccessful migration of trees

　　44.It can be inferred from the passage that ____________.

　　A.the developing world has decided to increase its energy consumption

　　B.a third-world citizen adds less than a ton of CO2 yearly to the atmosphere

　　C.the world climate would soon gain its balance if we stopped greenhouse gas emissions

　　D.future prosperity of the world is dependent on cheap fossil fuels

　　45.Which of the following is the main topic of the passage?____________

　　A.Impact of global warming on climate.

　　B.Prosperity and cheap fossil fuels.

　　C.Material progress and energy consumption.

　　D.Plants and animals in the changing climate.

　　参考答案：

　　41.B　第一段中的“feedback mechanisms”的意思最可能是：A动植物是如何适应隐蔽因素的;B动植物是如何与不断变化的气候相互作用的;C气候是如何变化的;D气候带是如何迁移的。

　　42.A　从文章中我们可以得知：A某些反馈机制可能减缓全球变暖的速度;B全球变暖的基本事实还不为人所知;C发展中国家从廉价的矿物燃料中获益;D发达国家打算降低能耗。

　　43.D　预测气候带的迁移将由下列哪一项伴随进行?A许多树木被砍伐;B有利的环境变化;C物种的成功迁移;D树木的不成功迁移。

　　44.B　从文章可以推断出：A发展中国家打算增加能源的消耗;B第三世界每年向大气层释放的二氧化碳，人均不超过一吨;C如果我们停止排放引起温室效应的废气，全球的气候就会获得平衡;D未来世界的繁荣靠廉价的矿物能源。
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