GWD5-32

Proposal:  Carbon dioxide and methane in the atmosphere block the escape[MSOffice1]  of heat into space.  So emission of these “greenhouse” gases contributes to global warming.  In order to reduce global warming, emission of greenhouse gases needs to be reduced.  Therefore, the methane now emitted from open landfills should instead be burned to produce electricity.

Objection:  The burning of methane[MSOffice2]  generates carbon dioxide that is released into the atmosphere.

Which of the following, if true, most adequately counters the objection made to the proposal?

1. Every time a human being or other mammal exhales, there is some carbon dioxide released into the air.
2. The conversion of methane to electricity would occur at a considerable distance from the landfills.
3. The methane that is used to generate electricity would generally be used as a substitute for a fuel that does not produce any greenhouse gases when burned
4. Methane in the atmosphere is more effective in blocking the escape of heat from the Earth than is carbon dioxide.
5. The amount of methane emitted from the landfills could be reduced if the materials whose decomposition produces methane were not discarded, but recycled.

d说m比co2危害更大，也就是说燃烧同等的m和co2,m更会加重温室效应。

所以即使烧m会放出co2,实际上，它还是减少了产生温室效应的热量。

不是完全没有热量，只是相对减少了而已。因此counter了反对者的proposal.

明白了。D甲烷比二氧化碳遮盖的更严重，应该减少更严重的甲烷—就是把甲烷燃烧了，既是变成任何物质或者二氧化碳，总比垃圾场的甲烷直接释放到空气中好。

谢谢聪明的jiaojiao