Q23 - The effects of global warming on the polar ice caps

[ohthatpatrick]

Question Type:
Explain/Resolve

Stimulus Breakdown:
Background: Models predict that if global temps go up 2 degrees, the ice caps would melt considerably.

Surprise: The same models say that the overall volume of the ice caps would increase, not shrink.

Answer Anticipation:
How can you melt considerably, but still go up in volume? The correct answer needs to tell us how, in a 2-degree warmer world, the ice caps could go up in volume.

Correct Answer:
A

Answer Choice Analysis:
(A) Okay, this'll work (at least for now). This gives us a way, in a warmer world, that ice caps would increase in volume: more snow on them that melts and refreezes.

(B) Stabilizing the size of the ice caps? That's the opposite of what we want. We need an increase in volume.

(C) This is about melting. We need to know how volume increases.

(D) "Lower temp needed to freeze seawater" certainly doesn't give us a clear reason why volume of ice caps increases.

(E) "Smaller variations between extreme climates" is not a reason why the ice caps increase in volume.

Takeaway/Pattern: This one should be pretty straightforward as long as we correctly found the surprise in the paragraph and kept it as our mantra as we evaluated answer choices: "Does THIS help me explain why the volume of the ice caps increased?" Once I saw, with (B), that these answer choices were going to be laid out the same way, I stopped reading anything but the final idea, since THAT's where our big causal takeaway was found in each answer choice.

#officialexplanation

[HumphreyY750]

Although some people would go D, I want to point out that D requires too much of filling the gaps: You have to assume that lower freezing point would in some way increase the ice cap. That is such a leap of faith.