A Sunshade for the Planet
Even with the best will1 in the world，reducing our carbon emissions is not going to prevent global warming.It has become clear that even if we take the most strong measures to control emissions，the uncertainties in our climate models still leaye open the possibility of extreme warming and rises in sea level.At the same time，resistance by governments and special interest groups makes it quite possible that the actions suggested by climate scientists might not be implemented soon enough.
Basically the idea is to apply sunscreen to the whole planet.One astronomer has come up with a radical plan to cool Earth;launch trillions of feather-light discs into space，where they would form a vast cloud that would block the suns rays.Its controversial，but recent studies suggest there are ways to deflect just enough of the sunlight reaching the Earths surface to counteract the warming produced by the greenhouse effect.Global climate models show that blocking just 1.8 per cent of the incident energy in the suns rays would cancel out the warming effects produced by a doubling of greenhouse gases in the atmosphere. That could be crucial，because even the most severe emissions-control measures being proposed would leave us with a doubling of carbon dioxide by the end of this century，and that would last for at least a century more.
1. According to the first two paragraphs，the author thinks that
B to reduce carbon emissions is all impossible mission.
D actions suggested by scientists will never be realized.
A know what they are doing.
C think the problem has been solved.
3. What does Stephen Schneider say about a heroin addict and methadone?
B Methadone is not a correct way to treat a heroin addict.
D Methadone and heroin are equally effective in treating a heroin addict.
A To ask governments to take stronger measures;
C To apply sunscreen to the Earth.
5. What is NOT true of the effectiveness of sunscreen，according to the last paragraph?
B It blocks the incident energy in the suns rays.
D It decreases greenhouse gases in the atmosphere.
1. C 2. C 3. A 4. C 5. D