Self-study
The effects of global warming on the polar ice caps have been studied with computer models. █████████ ██ ████ ███████ ██ ███ ██████ ███████████ █████████ ██ ██ ██████ ██ ███ ███████ ████████ ███ ████████ ████ ████ ██ █ ███████████ ████ █████ ████ ███ ███ ████ █████████████ ████████ █████ ██████ ████ ████ ████ █████ ████ █ █████████ ███ ██████ ██ ███ ███ ████ █████ █████████ ███ ███████
"Surprising" Phenomenon
Models show that a rise in global temperatures would melt the ice caps considerably, but the models also preduct that the ice caps would increase in total volume.
Objective
The correct answer will be a hypothesis that explains how something that considerably melts the polar ice caps can also increase their volume. This explanation must result in the ice caps' growth outweighing their shrinkage from melting, and provide some mechanism for how this growth occurs.
23.
Which one of the following, ██ █████ █████ ████ ████ ██ ███████ ███ ████████ ███████ █████████ ██████
a
As global temperatures █████████ ████ ████████ ██████████ ████ ███ ███████████ ███████ ███████ ██ █████████ ████████ ██ ███ █████ █████ █████ ████ █████ ███ █████████ ██ ████
While a temperature increase would melt the ice caps, it would also cause increased snowfall at the polar caps. In turn, the ice caps would grow in total volume once the snow refreezes into ice. This accounts for both melting and volume growth.
b
As global temperatures █████████ ████ ████████ ██████████ ████ ███ ███████████ ███████ ████████ ███ █████ ██████ █████ ████ ███████ ██ ████ ███████ ███████ ███ ███ ████ ███ ███ ██████ ██████ ███████ ███████████ ███ ████ ██ ███ ███ █████
According to the stimulus, the ice caps would grow. This says they remain stable, so doesn't resolve the paradox.
c
As sea temperatures █████████ ███ ██████████ ██ ███████████ ███████ ███ █████ ███ ████ ███ ███ ████████ █████ ███████ ████████ █████ ██ ████ ██████ ███ █████ ██ ████ ███ ███ ██ ████████ ██ █ ██████ █████
This intensifies the rate at which ice caps melt, but it doesn’t explain why the ice caps would grow in volume.
d
As sea temperatures █████████ ███████████ ██ ████████ ██████ ███ █████████████ ██ ████ ██ ███ █████ ██ █████████ █████ ███████ ██████ ███ ███████████ ██████ ██ ██████ ███ █████████
If the temperature needed to freeze seawater falls even further, then it seems even less likely that the ice caps would grow in volume.
e
As global temperatures █████████ ████ ████████ ██████████ ████ ███ ███████████ ███████ ███████ ██ █████████ █████ ██████████ █████ ██████ ███████ ██████████ ███████ ███ ███████ ████████████ ██ ███ ███████ ███████ ████████ ███ █████ ██ ███ ███████ █████████
Unless those variations explain how ice cap volume would grow, we don’t care about them. This doesn’t tell us what effect the variations would have, so it's not useful.