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Science · Drill 7

Science practice 7

14 questions ~9 min recommended
⏱ 00:00
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The majority of scientists agree that global temperatures are rising, leading to a host of climate changes that will produce significant worldwide effects over time. Still subject to debate are the type and severity of effects that these climate changes will have on various industries. Two scientists present their viewpoints regarding the effects of climate change on agriculture in the United States.

Scientist 1

Climate change is likely to have mixed effects on U.S. agriculture over time. Every crop has a set of optimal conditions under which it grows and reproduces best. For many crops, the growth rate increases as temperature increases, suggesting that the progressive increase in average temperatures will have a beneficial effect on many types of crops. On the other hand, a faster growth rate means less time for the seeds of certain crops to mature, hindering their reproductive ability. Average temperatures will eventually surpass the optimal growth temperature for some crops, causing their yields to decline.

Crop yields also increase with carbon dioxide levels1. The positive growth effect of carbon dioxide can be suppressed, however, if the optimal growth temperature is surpassed. The potential effects of climate change on other environmental conditions, including soil moisture, nutrient levels, and water availability must be taken into account as well.

Scientist 2

Agriculture in the United States will be adversely affected by climate change over the next several decades. Many weeds, pests, and fungi thrive in warm, wet climates and with increased levels of carbon dioxide. As average temperatures continue to increase and these conditions become more widespread, the habitat ranges for these organisms will spread northward. This will pose challenges to northern crops that have not previously been exposed to certain competitors and pests.

The predicted increase in extreme weather events will also negatively impact crop yields. An increase in the frequency of floods will destroy crops and potentially deter farming along major waterways altogether. In areas in which drought conditions are projected to become more common, a water supply capable of sustaining even modest crop yields is a very real concern.

The majority of scientists agree that global temperatures are rising, leading to a host of climate changes that will produce significant worldwide effects over time. Still subject to debate are the type and severity of effects that these climate changes will have on various industries. Two scientists present their viewpoints regarding the effects of climate change on agriculture in the United States.

Scientist 1

Climate change is likely to have mixed effects on U.S. agriculture over time. Every crop has a set of optimal conditions under which it grows and reproduces best. For many crops, the growth rate increases as temperature increases, suggesting that the progressive increase in average temperatures will have a beneficial effect on many types of crops. On the other hand, a faster growth rate means less time for the seeds of certain crops to mature, hindering their reproductive ability. Average temperatures will eventually surpass the optimal growth temperature for some crops, causing their yields to decline.

Crop yields also increase with carbon dioxide levels. The positive growth effect of carbon dioxide can be suppressed, however, if the optimal growth temperature is surpassed. The potential effects of climate change on other environmental conditions, including soil moisture, nutrient levels, and water availability must be taken into account as well.

Scientist 2

Agriculture in the United States will be adversely affected by climate change over the next several decades. Many weeds, pests, and fungi thrive in warm, wet climates and with increased levels of carbon dioxide. As average temperatures continue to increase and these conditions become more widespread, the habitat ranges for these organisms will spread northward. This will pose challenges to northern crops that have not previously been exposed to certain competitors and pests.

The predicted increase in extreme weather events will also negatively impact crop yields. An increase in the frequency of floods will destroy crops and potentially deter farming along major waterways altogether. In areas in which drought conditions are projected to become more common, a water supply capable of sustaining even modest crop yields is a very real concern.

1. According to Scientist 1, how will a change in average temperature affect the growth rates of crops?

2. If Scientist 1 is correct, which of the following trends will most likely occur over the next several decades?

3. Which environmental change was discussed by Scientist 2, but not Scientist 1?

4. Scientist 2 did not predict that climate change would cause an increase in which of the following factors affecting crop yields?

5. Based on the passage, the major difference between the opinions of Scientists 1 and 2 is that:

6. Scientist 2 states that high:

7. An industry-wide increase in agricultural pesticide use over the next several decades would support the opinion of:

8. According to Scientist 1, what happens when a crop's optimal growth temperature is surpassed?

9. Based on the information in the passage, both scientists would agree with which of the following statements?

10. It can be inferred that Scientist 1 believes elevated levels of carbon dioxide will directly lead to crops with a(n):

11. Which of the following does Scientist 2 identify as potential competitors to northern crops?

12. The hypothesis of Scientist 1 could best be tested by recording data over the next decade on:

13. If Scientist 2 is correct, over time, the range of:

14. Assuming that increasing carbon dioxide levels cause average temperature to increase, which graph best represents the relationship between carbon dioxide level and crop yields, according to Scientist 1?

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