For the first time in the scientific community, there is total agreement that the activity of humans is at least partly responsi

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问题    For the first time in the scientific community, there is total agreement that the activity of humans is at least partly responsible for the rise of global temperature — specifically the emission of greenhouse gases like carbon dioxide, which is released by the burning of wood, coal and petroleum products. Reducing harmful emissions is just one area in which the United Nations Intergovernmental Panel is decidedly optimistic. For one thing, in the short term it might not prove that difficult. Efficiency improvements alone could cut energy needs by as much as 30 percent at virtually no extra cost and, in developed countries, emission reductions of up to 60 percent "are technically feasible". In the longer term, harmful emissions will be reduced as the world changes over to cheaper, less environmentally damaging energy sources.
   So, if it is economically and technically feasible to reduce harmful emissions, why is almost nothing being done? There are two main reasons. The first stems from the uncertainty about how hot the planet is going to get. The current estimate is extremely broad — between 0.8 and 3.5 degrees Celsius by 2100. If the former prediction is accurate, it may be that we can adapt to it without difficulty. If, on the other hand, the latter is closer to reality, a complete rethink of the world’s energy supplies is already long overdue.
   This leads directly to the second problem — the time scale involved. It is difficult to get people to act when predictions may take between 50 and 100 years to materialize. For politicians, who face elections every half decade or so. preventative action against a future threat — the magnitude of which is still very uncertain — carries heavy political risks.
   Even if politicians in the developed world were to be forced into action, what of the developing world. which is economically dependent on fossil fuels? Should it reduce emissions, and suffer the consequences, because of mistakes made by the developed world? One suggestion is that developing countries be given allowances above the current emission standards. This would enable them to meet their industrialized needs and ultimately help them to finance environmentally sound technologies. This would seem the only realistic way of getting agreement from developing countries — a vital requirement because, if preventative action is going to work, you really do have to have everyone on board.  
In the longer span of the future what is most important in reducing harmful emissions?

选项 A、Efficiency improvements.
B、New energy sources.
C、New technologies.
D、Burning less of wood. coal and petroleum.

答案B

解析 参考第一段最后一句,改用更经济和危害更少的燃料是减少废气排放的根本,所以选B。
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