Proposal: Carbon dioxide and methane in the atmosphere block the escape 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 generates carbon dioxide that is released into the atmosphere.
Which of the following, if true, most adequately counters the objection made to the proposal?
(A) Every time a human being or other mammal exhales, there is some carbon dioxide released into the air.
(B) The conversion of methane to electricity would occur at a considerable distance from the landfills.
(C) 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.
(D) Methane in the atmosphere is more effective in blocking the escape of heat from the Earth than is carbon dioxide.
(E) The amount of methane emitted from the landfills could be reduced if the materials whose decomposition produces methane were not discarded, but recycled.
Let’s understand the argument and the objection first
1)Carbon dioxide and methane in the atmosphere block the escape of heat into space.
2) So emission of these “greenhouse” gases contributes to global warming.
3) In order to reduce global warming, the emission of greenhouse gases needs to be reduced.
Proposal/ Conclusion- Therefore, the methane now emitted from open landfills should instead be burned to produce electricity.
Objection/Counter conclusion- The burning of methane generates carbon dioxide that is released into the atmosphere.
We need to find an option that weakens the objection to the proposal.
(A) Every time a human being or other mammal exhales, there is some carbon dioxide released into the air.
The objection is against burning methane as burning methane generates carbon dioxide that is released into the atmosphere. Option A is irrelevant to the conclusion as well as the counter conclusion- Eliminate A
(B) The conversion of methane to electricity would occur at a considerable distance from the landfills.
It doesn’t matter where the conversion occurs. Eliminate B
(C) 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.
The objection is that the burning of methane generates carbon dioxide that is released into the atmosphere.
This option does not go against the objection of burning methane. It only tells us that 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. This supports the objection and is hence incorrect.
(D) Methane in the atmosphere is more effective in blocking the escape of heat from the Earth than is carbon dioxide.
Carbon dioxide and methane in the atmosphere block the escape of heat into space.
Objection- the burning of methane generates more carbon dioxide that is released into the atmosphere
D says that Methane in the atmosphere is more effective in blocking the escape of heat from the Earth than is carbon dioxide.
This means that Methane in the atmosphere is more harmful than is CO2 as methane contributes more to global warming than CO2 does. Hence burning Methane (even if it generates C02) is better than leaving the methane in the atmosphere. Hence option D is correct
(E) The amount of methane emitted from the landfills could be reduced if the materials whose decomposition produces methane were not discarded, but recycled.
This is totally irrelevant to the argument and the objective. Hence incorrect.