Malthusian fears that population growth will outstrip food supplies have been widely discounted as food production has kept well ahead of growing human numbers in the last half century. While population doubled, food supply tripled, and life expectancy increased from 46 in the 1950s to around 65 today. But more recently, some experts have once again been sounding the alarm about a possible food crisis.
The reason lies in the combined impact of many factors including climate change, forest denudation, land degradation, water shortage, declining oil supplies, species extinction, destruction of coastal ecosystems and the growing demands for a meat-rich diet from newly developed parts of the world.
At the root of all these problems has been the ruthless exploitation of the earth’s resources, fuelled by growing affluence in some parts of the world and desperate poverty in others. Between 1980 and 2000, global population rose from 4.4 billion to 6.1 billion, while food production increased 50 per cent. By 2050, the population is expected to reach 9 billion.
Data shows that while grain yields per acre have been increasing, the rate of increase has been slowing since the days of the Green Revolution in the 1970s. Most of the benefits of irrigation, machinery, fertilizer and plant breeding have already been realized. The production of grain per acre is close to the maximum obtainable through photosynthesis.
To keep up with the growth in human population, more food will have to be produced over the next 50 years than has been during the past 10,000 years combined, said the participants of the recent UN-backed forum in Iceland on sustainable development. It is, of course, possible that new technologies, smart environmental management and sensitive social policies will combine to good effect to usher in a new green revolution. But as grain reserves have fallen to their lowest level for many years, this cannot be guaranteed.
At the 1996 World Food Summit political leaders from 186 countries pledged to halve the number of hungry people in the world by the year 2015, or a reduction of 20 million each year. At that time, about 800 million people were reported to suffer from under- nourishment. In 2007 estimates from the UN Food and Agriculture Organization (FAO) suggest that there are 854 million people who do not get enough to eat every day. "Far from decreasing, the number of hungry people in the world is currently increasing," said FAO Director-General Jacques Diouf. (Of course, world population has increased by some 800 million in that time, so food supplies have kept up relatively well, but have failed to reach an increasing number, let alone reduce the total going hungry.)
According to the passage, the Green Revolution in the 1970s（）
A. witnessed the slowing down of the increase of grain output
B. caused many innovative measures to be taken to promote crop production
C. appeared as the environmental situation degraded
D. reached a record high in food production
参考答案：B
解析：
[试题类型] 具体信息题。
[解题思路] 根据题干关键词the Green Revolution in the 1970s可定位至文章第四段。该段首句指出，自从70年代绿色革命之后，粮食产量增长的比率一直在下降。紧接着指出灌溉、施肥等现代化手段的最大成效已经基本实现了。由此可以推知，在绿色革命时代，人们采取了许多革新措施提高粮食产量，故选项[B]正确。
[干扰排除] 选项[A]根据第四段首句中the rate of increase has been slowing设置干扰，根据本句内容，粮食增长量的下降是绿色革命之后的事情(since the days of the Green Revolution in the 1970s)，故排除。选项[C]中the environmental situation degraded对应文章第二段的climate change, forest denudation...destruction of coastal ecosystems，但自然环境的恶化是导致粮食危机的原因，并不是随着环境恶化才出现绿色革命，故排除选项[C]。选项[D]中的a record high是根据第四段末句the maximum设置的干扰。该句指出，现在粮食产量接近通过光合作用可达到的最高值，而不是指70年代绿色革命时期粮食产量达到最高值，且由该段首句中grain yields per acre have been increasing可知，粮食产量一直在增长，因此70年代绿色革命时期的粮食产量不会是最高纪录，故排除选项[D]。