Global warming means that US farms are likely to increase production of soybeans, cotton, sorghum and oranges during the coming

admin2011-01-02  63

问题    Global warming means that US farms are likely to increase production of soybeans, cotton, sorghum and oranges during the coming decades, according to a new US government report.
   Farmers will also need less irrigation water and more pesticides because of slightly warmer temperature expected across the continental United States from carbon emissions, the Environmental Protection Agency report said.
   In the document, the Bush administration endorsed for the first time the widely held view of scientists that US greenhouse gas emissions will rise significantly over the next two decades due mostly to human activities.
   The White House had previously said there was not enough scientific evidence to blame oil refining, power plants and automobile emissions for global warming. The administration has rejected participating in the international Kyoto treaty to reduce greenhouse gases, saying a less costly and effective approach is to encourage voluntary emission cuts by industry.
   Although climate change could threaten US barrier islands and mountain meadows, the EPA report said most American farmers had little to worry about.
   The US has more than 1 billion acres of farmland, pastures and grazing land.
   The rising concentration of carbon dioxide in the soil is beneficial to many crops and should help continue decades of rising crop yields, the report said.
   Higher concentrations of carbon dioxide in the soil and slightly warmer temperature should benefit crops such as cotton, corn, soybeans, sorghum, barley, sugar beets and citrus fruits. "In general, northern areas such as the Midwest, West and Pacific Northwest are projected to show large gains in yields, while influences on crop yields in other regions vary more widely," the report said.
   For example, some scientific studies cited by the report estimated soybean crop yields could climb by 23 percent to 40 percent, depending on the specific scenario of rainfall and temperature. Orange crop yields could soar by 13 percent to 120 percent. However, corn yields would climb by a more modest 1 percent to 9 percent, the report said.
   More carbon also helps the soil hold water and plants grow faster, so that farmers will need less irrigation water, the EPA report said. However, climate change also means many growers will need to use more pesticides, the report said without elaboration.
   The EPA acknowledged that scientific analyses have not considered all of the consequences of climate change. on crop pests, diseases and extreme weather. "Agricultural technology is currently undergoing rapid change, the future production technologies and practices seem likely to be able to contain or reduce these impacts," the EPA report said.
   Farmers in the Southeast face more uncertainties linked to climate change.
   The EPA report said a change in planting dates and genetically altered crop varieties will be important for the Southeast in case summer rainfall declines.
What kind of attitude does the EPA report hold towards the unfavorable impact of climate change on the future agriculture of America?

选项 A、Impartial.
B、Pessimistic.
C、Optimistic.
D、Neutral.

答案C

解析 倒数第三段美国环保局的报告声称,目前农业技术正发生迅速变化,未来生产技术和实践有可能控制或减少气温升高带来的不良影响。因此,该报告对美国农业的前途是有信心的,正确答案为C。
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