34 According to the passage, which of the following statements is true about global warming?
(A) It would lead to a shrink in world population.
(B) It may trigger a mechanism that would lower the temperature.
(C) It could sharply increase the amount of carbon dioxide in the atmosphere.
(D) A massive movement of population would be inevitable.

答案：登入後查看
統計： A(9), B(93), C(49), D(16), E(0) #1150833

詳解 (共 2 筆)

#3710958
Nobody knows what the global temperature is likely to be in the future, for the climate is a system of almost infinite無限 complexity.
Predicting how much hotter a particular level of carbon dioxide will make the world is impossible.
It’s not just that the precise精確 effect of greenhouse gases on temperature is unclear.
It may set off mechanisms that tend to cool things down (clouds which block out擋住 sunlight, for instance例如) or ones that heat the world further (by melting soils泥土，土壤 in which greenhouse gases are frozen, for instance).
The system could right itself or spin旋转 out of human control. 
This uncertainty is central to the difficulty of tackling the problem.
Since the costs of climate change are unknown, the benefits of trying to do anything to prevent it are, by definition解釋，說明, unclear.
What’s more, if they accrue at all, they will do so at some point in the future.
So is it really worth using public resources now to avert避免, 防止 an uncertain, distant遙遠 risk, especially when the cash could be spent instead作為替代 on goods and services that would have a measurable near-term benefit?
If the risk is big enough, yes. Governments do it all the time. They spend a small slice of tax revenue（政府的）稅收，歲入 on keeping standing armies not because they think their countries are in imminent臨近 danger of invasion入侵 but because, if it happened, the consequences would be catastrophic悲慘的,災難. 
Individuals do so, too. They spend a little of their incomes on household insurance not because they think their homes are likely to be torched火把 next week but because, if it happened, the results would be disastrous.
Similarly, a growing body of scientific evidence suggests that the risk of a climatic catastrophe悲慘的,災難 is high enough for the world to spend a small proportion數量, 部分；份額, 比率 of its income trying to prevent one from happening. 
4
0
#1268992
set off mechanism 啟動機制
2
0