Brown L R
Popul Bull. 1981 Sep;36(3):1-44.
This bulletin examines the narrowing margin between global food production and population growth. Between 1950 and 1971, world grain production nearly doubled and per capita production increased 31%. During the 1970s, gains in output barely kept pace with population growth, consumption/person declined in sub-Saharan Africa and parts of Asia, food prices were volatile, and over 100 food deficit countries came to depend on the exportable surplus of North America, now the only major grain exporting region. The world fish catch levelled off in the early 1970s and beef production, still dependent mainly on grassland grazing, levelled off in the mid-1970s. With little new land left to plow, satisfying increased food demand now depends on sharp increases in yields on existing crop land. Worldwide, this effort is hampered by loss of topsoil and irrigated land, conversion of cropland to nonfarm uses, rising energy costs, inefficient agrarian structures, particularly in the Soviet Union, the falling yield response to chemical fertilizers in agriculturally advanced countries, and the emerging competition between food and agriculturally based energy crops. Green Revolution successes in some developing countries deomonstrate that, given the right inputs, 3rd world farmers can increase crop yields dramatically. Feeding the world's poor also requires more equitable income and food distribution, including a reduction in the proportion of grain and fish consumed indirectly as livestock products by the affluent. Most important in meeting food needs on a finite planet is braking population growth. The author concludes that every effort should be made to stabilize world production at abour 6 billion by 2020, rather than 10.5 billion by 2110, as is now projected by the UN.
本公报审视了全球粮食产量与人口增长之间日益缩小的差距。1950年至1971年间,世界粮食产量几乎翻了一番,人均产量增长了31%。在20世纪70年代,产量的增长勉强跟上人口增长的步伐,撒哈拉以南非洲和亚洲部分地区的人均消费量下降,粮食价格波动不定,100多个粮食短缺国家开始依赖北美可出口的盈余粮食,北美现在是唯一的主要粮食出口地区。世界捕鱼量在20世纪70年代初趋于平稳,而主要仍依赖草地放牧的牛肉产量在20世纪70年代中期趋于平稳。由于可供开垦的新土地所剩无几,满足不断增长的粮食需求现在取决于现有耕地单产的大幅提高。在全球范围内,这项努力受到表土和灌溉土地流失、农田转作非农业用途、能源成本上升、农业结构低效(特别是在苏联)、农业发达国家化肥增产效应下降以及粮食作物与以农业为基础的能源作物之间新出现的竞争等因素的阻碍。一些发展中国家绿色革命的成功表明,只要有合适的投入,第三世界的农民就能大幅提高作物产量。养活世界上的贫困人口还需要更公平的收入和粮食分配,包括减少富裕阶层间接作为畜产品消费的谷物和鱼类比例。在一个有限的星球上满足粮食需求,最重要的是抑制人口增长。作者得出结论,应尽一切努力到2020年将世界产量稳定在约60亿,而不是如联合国目前预测的到2110年达到105亿。