In a plausible but speculative scenario, oceanographer Douglas Martinson suggests that temperature increases caused by global wa

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问题 In a plausible but speculative scenario, oceanographer Douglas Martinson suggests that temperature increases caused by global warming would not significantly affect the stability of the Antarctic environment, where sea ice forms on the periphery of the continent in the autumn and winter and mostly disappears in the summer. True, less sea ice would form in the winter because global warming would cause temperatures to rise. However, Martinson argues, the effect of a warmer atmosphere may be offset as follows. The formation of sea ice causes the concentration of salt in surface waters to increase; less sea ice would mean a smaller increase in the concentration of salt. Less salty surface waters would be less dense and therefore less likely to sink and stir up deep water. The deep water, with all its stored heat, would rise to the surface at a slower rate. Thus, although the winter sea-ice cover might decrease, the surface waters would remain cold enough so that the decrease would not be excessive.
The passage suggests that Martinson believes which of the following about deep waters in the Antarctic region?

选项 A、They rise to the surface more quickly than they would if global warming were to occur.
B、They store heat that will exacerbate the effects of increases in atmospheric temperatures.
C、They would be likely to be significantly warmed by an increase in atmospheric temperatures.
D、They would be more salty than they currently are if global warming were to occur.
E、They are less likely to be stirred up when surface waters are intensely salty than when surface waters are relatively unsalty.

答案A

解析 Choice A is correct. The passage states that, in Martinsons scenario, the deep water would rise to the surface at a slower rate were warming to occur. He must believe, then, that the water currently rises to the surface more quickly. As for Choice B, while the passage indeed states that deep waters in Antarctica store heat, it also suggests that this heat would be less likely to reach the surface and worsen global warming. Choice B is therefore incorrect. Choice E is incorrect because it contradicts information given in the passage. Choices C and D are incorrect because, while the passage discusses the effects of global warming on the temperature and salinity of surface water, it gives no information of warmings effects on the temperature and salinity of deep water.
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