【单选题】
2
Climatic conditions are delicately adjusted to the composition of theEarth’s atmos phere. If there were a change in the atmosphere—for example, in the relative proportions of atmosphere gases—the climate would probably change also.A、slight increase in water vapor, for instance, would increase the hem-retaining capacity of the atmosphere and would lead to a rise in global temperatures. In contrast, a large increase in water vapor would increase the thickness and extent of the cloud layer, reducing the mount of solar en ergy reaching theEarth’surface.
The level of carbon dioxide,CO2 in the atmosphere has important effect on climatic change. Most of theEarth’s incoming energy is short-wavelength radiation, which tends to pass through atmosphericCO2 easily. TheEarth, however, reradiates much of the re ceived energy as a long-wavelength radiation, whichCO2 absorbs and then remits toward theEarth. This phenomenon, known as the greenhouse effect, can result in an increase in the surface temperature of a planet.An extreme example of the effect is shown by the Ve- nus, a planet covered by heavy clouds composed mostly ofCO2, whose surface tempera tures have been measured at 43℃. If theCO2 content of the atmosphere is reduced, the temperature falls.According to one respectable theory, if the atmosphericCO2 concentra tion were halved, theEarth would become completely covered with ice.Another equally respectable theory, however, states that a halving of theCO2 concentration would lead only to a reduction in global temperatures of 3℃.
If, because of an increase in forest fires or volcanic activity, theCO2 content of the atmosphere increased, a warmer climate would be produceD、Plant growth, which relies on both the warmth and the availability ofCO2, would probably increase.As a consequence, plants would use more and moreCO2，EventuallyCO2 levels would diminish and the cli mate, in turn, would become cooler. With reduced temperatures many plants would die;CO2 would thereby be returned to the atmosphere and gradually the temperatures would rise again. Thus, if this process occurred, there might be a long-term oscillation in the amount ofCO2 present in the atmosphere, with regular temperature increase and decrease of a set magnitude.
Some climatologists argue that the burning of fossil fuels has raised the level ofCO2 in the atmosphere and has caused a global temperature rise of at least 1℃.But a supposed global temperature rise of 1℃ may in reality be only several regional temperature increase, restricted to areas where there are many meteorological stations and caused simply by shifts in the pattern of atmospheric circulation. Other areas, for example the Southern Hemi sphere oceanic zone, may be experiencing an equivalent temperature decrease that is unrec ognized because of the shortage of meteorological recording stations.
The passage suggests that a large decrease in the amount ofCO2 in the atmosphere would result in______.A．at least a slight decrease in global temperatures
B．at the most a slight increase in short-wavelength radiation reaching the earth
C．a slight long-term increase in global temperatures
D．a slight short-term increase in global temperatures
网考网参考答案：A
网考网解析：
[解析] 本题的四个选项中，只有A项为正确答案。这可从文中第二段的最后几句话推知，即在这几句中作者介绍了两种理论：根据第一个理论，如果大气中的CO 2 减半， 地球就会完全被冰所覆盖。根据第二个理论，如果大气中CO 2 的含量减半，全球气温会下降三摄氏度。据此可知，这篇文章暗示大气中CO 2 含量锐减至少会导致全球气温小幅 度下降。 document.getElementById("warp").style.display="none"; document.getElementById("content").style.display="block"; 查看试题解析出处>>
Climatic conditions are delicately adjusted to the composition of theEarth’s atmos phere. If there were a change in the atmosphere—for example, in the relative proportions of atmosphere gases—the climate would probably change also.A、slight increase in water vapor, for instance, would increase the hem-retaining capacity of the atmosphere and would lead to a rise in global temperatures. In contrast, a large increase in water vapor would increase the thickness and extent of the cloud layer, reducing the mount of solar en ergy reaching theEarth’surface.
The level of carbon dioxide,CO2 in the atmosphere has important effect on climatic change. Most of theEarth’s incoming energy is short-wavelength radiation, which tends to pass through atmosphericCO2 easily. TheEarth, however, reradiates much of the re ceived energy as a long-wavelength radiation, whichCO2 absorbs and then remits toward theEarth. This phenomenon, known as the greenhouse effect, can result in an increase in the surface temperature of a planet.An extreme example of the effect is shown by the Ve- nus, a planet covered by heavy clouds composed mostly ofCO2, whose surface tempera tures have been measured at 43℃. If theCO2 content of the atmosphere is reduced, the temperature falls.According to one respectable theory, if the atmosphericCO2 concentra tion were halved, theEarth would become completely covered with ice.Another equally respectable theory, however, states that a halving of theCO2 concentration would lead only to a reduction in global temperatures of 3℃.
If, because of an increase in forest fires or volcanic activity, theCO2 content of the atmosphere increased, a warmer climate would be produceD、Plant growth, which relies on both the warmth and the availability ofCO2, would probably increase.As a consequence, plants would use more and moreCO2，EventuallyCO2 levels would diminish and the cli mate, in turn, would become cooler. With reduced temperatures many plants would die;CO2 would thereby be returned to the atmosphere and gradually the temperatures would rise again. Thus, if this process occurred, there might be a long-term oscillation in the amount ofCO2 present in the atmosphere, with regular temperature increase and decrease of a set magnitude.
Some climatologists argue that the burning of fossil fuels has raised the level ofCO2 in the atmosphere and has caused a global temperature rise of at least 1℃.But a supposed global temperature rise of 1℃ may in reality be only several regional temperature increase, restricted to areas where there are many meteorological stations and caused simply by shifts in the pattern of atmospheric circulation. Other areas, for example the Southern Hemi sphere oceanic zone, may be experiencing an equivalent temperature decrease that is unrec ognized because of the shortage of meteorological recording stations.
The passage suggests that a large decrease in the amount ofCO2 in the atmosphere would result in______.A．at least a slight decrease in global temperatures
B．at the most a slight increase in short-wavelength radiation reaching the earth
C．a slight long-term increase in global temperatures
D．a slight short-term increase in global temperatures
网考网参考答案：A
网考网解析：
[解析] 本题的四个选项中，只有A项为正确答案。这可从文中第二段的最后几句话推知，即在这几句中作者介绍了两种理论：根据第一个理论，如果大气中的CO 2 减半， 地球就会完全被冰所覆盖。根据第二个理论，如果大气中CO 2 的含量减半，全球气温会下降三摄氏度。据此可知，这篇文章暗示大气中CO 2 含量锐减至少会导致全球气温小幅 度下降。 document.getElementById("warp").style.display="none"; document.getElementById("content").style.display="block"; 查看试题解析出处>>
发布评论 查看全部评论