单选题
The shorter growing seasons expected with climate change over the next 40 years will endanger hundreds of millions of already poor people in the global tropics, say researchers working with the world's leading agricultural organisations. The effects of climate change are likely to be seen across the entire tropical 25 but many areas previously considered to be 26 food secure are likely to become highly vulnerable to droughts, extreme weather and higher temperatures, say the researchers with the Consultative Group on International Agricultural Research. Intensively farmed areas like northeast Brazil and Mexico are likely to see their 27 growing seasons fall below 120 days, which is 28 for crops such as corn to mature. Many other places in Latin America are likely to 29 temperatures that are too hot for bean production, a staple in the region. The impact could be felt most in India and southeast Asia. More than 300 million people in south Asia are likely to be affected even with a 5% decrease in the 30 of the growing season. Higher peak temperatures are also expected to take a heavy 31 on food producers. Today there are 56 million crop-dependent people in parts of west Africa and India who live in areas where, in 40years, maximum daily temperatures could be higher than 30℃. This is close to the maximum temperature that beans can tolerate, while corn and rice yields suffer when temperatures 32 this level. 'We are starting to see much more clearly where the effects of climate change on agriculture could 33 hunger and poverty , 'said research leader Patti Kristjanson. 'Farmers already adapt to variable weather by changing their planting schedules. What this study suggests is that the speed of climate 34 and the magnitude of the changes required to adapt could be much greater.' A. shifts B. lessen C. width D. experience E. critical F. prime G. vulnerable H. zone I. intensify J. exceed K. toll L. length M. gradually N. immune O. relatively