noboru wrote:
George: Some scientists say that global warming will occur because people are releasing large amounts of carbon dioxide into the atmosphere by burning trees and fossil fuels. We can see, though, that the predicted warming is occurring already. In the middle of last winter, we had a month of springlike weather in our area, and this fall, because of unusually mild temperatures, the leaves on our town’s trees were three weeks late in turning color.
Which one of the following would it be most relevant to investigate in evaluating the conclusion of George’s argument?
(A) whether carbon dioxide is the only cause of global warming
(B) when leaves on the trees in the town usually change color
(C) what proportion of global emissions of carbon dioxide is due to the burning of trees by humans
(D) whether air pollution is causing some trees in the are to lose their leaves
(E) whether unusually warm weather is occurring elsewhere on the globe more frequently than before
Seemed odd to me at first glance
Very often, when atacking a CR question , we must look at the CONCLUSION, premises just to support the conclusion and they should not be touched.
Premise 1 ( provided by very smart people!) : global warming will occur because people are releasing large amounts of carbon dioxide into the atmosphere, so:
the release of CO2 leads -> to global warmingPremise/evidence 2: we had a month of springlike weather AND this fall the leaves on our town’s trees were three weeks late in turning color.
Evidence of warm weather is provided.
We begin to believe in the premise 1 provided by scientists and the evidence provided in premise 2.
Conclusion is : the predicted warming is occurring already Ok so far? Good.
to undermine the conclusion we must cast doubts on CONCLUSION AND not on premises, as they are often unchangeable.
(A) whether carbon dioxide is the only cause of global warming -
we don't care about the cause or whether it is only one or may be two casues - this atacks premise 1, we care about only "warming is occurring already"(B) when leaves on the trees in the town usually change color -
usually? so what? this refers to premise 2, we keep in mind that "warming is occurring already" - not relevant, eliminate it!(C) what proportion of global emissions of carbon dioxide is due to the burning of trees by humans -
- irrelevant: 1.since atacks premise not conclusion, 2. carbon dioxide proportion due to "the burning of trees by humans" is smaller when comparing to burning fossil fuels. (D) whether air pollution is causing some trees in the area to lose their leaves -
it may cause or it may not, but how does it refers to conclusion? - eliminate it! moreover, D talks about polution and trees to lose their leaves, something about warming? No! move on. (E) whether unusually warm weather is occurring elsewhere on the globe more frequently than before -
THIS IS IT!
What if the warm weather is occurring elsewhere on the globe with the same frequency as before? If yes, it is occuring then the predicted warming is NOT occurring already - it really atacks the conclusion! please give KUDOS if you like my explanations!