By the beginning of the 19th century, the world population had grown to a billion individuals, and intellectuals such as Thomas Malthus predicted that humankind would outgrow its available resources, because a finite amount of land would be incapable of supporting a population with a limitless potential for increase.
在十九世纪之初，世界人口增到了10亿人，托马斯·马尔萨斯等知识分子预测可利用资源会跟不上，因为土地有限，无法支持潜力无限的增长。