請依下文回答第 31 題至第 34 題Climate scientists vigorously debate about how bad global warming will get, how quickly, and how to combatit. One fight involves how much effort to put into stopping leaks of methane gas into the atmosphere. Someacademics complain that President Obama’s plan to make greater use of natural gas, which consists mostly ofmethane, will lock America into a supposed solution to climate change that will be worse than burning coal. Isthat claim plausible? The basic scientific facts are clear. The most important greenhouse gas that humans arespewing into the atmosphere is carbon dioxide, which comes from burning fossil fuels. The second mostimportant is methane, which is released when coal is mined; it escapes when wells are drilled for oil; and it leaksfrom pipes that distribute natural gas. Methane is a far more potent greenhouse gas than carbon dioxide. But instark contrast to CO2, methane breaks down quickly in the atmosphere. Scientists say, “Methane is like a hangoverthat you can get over it if you stop drinking,” said Dr. Pierrehumbert. “CO2 is more like lead poisoning—it sticksaround, you don’t get rid of it, and it causes irreversible harm.” So what has all this got to do with the President’sclimate plan? Mr. Obama’s administration intends to cut carbon dioxide emissions from power plants by 30percent, from 2005 levels, by 2030. That will push states toward much greater use of natural gas to generateelectricity—a shift that is seen as combating global warming because, in a power plant, burning natural gas emitsroughly half the carbon dioxide as burning coal. Experts say that it is critical to keep carbon dioxide out of theatmosphere now, even if that requires burning more gas.If only a limited amount of money is going to be available to tackle global warming, that would weigh in favorof Dr. Pierrehumbert’s argument for ignoring methane leaks for the time being. Dr. Shindell, a NASA climatescientist, agrees that methane control should not be pursued at the expense of CO2 control.There might be a way out of this conundrum. The idea would be to promise far more aggressive methanecontrol to slow global warming for the benefit of people alive today, along with aggressive CO2 control for thebenefit of future generations.
31 What does President Obama propose to curb the greenhouse gases?
(A) To stop the leaking of methane.
(B) To make more use of natural gas.
(C) To burn more coals.
(D) To take advantage of fossil fuels.