Theodore W. Schultz

[T]here is an abundance of rhetoric consisting of dire predictions that the soils of the earth are being depleted, natural resources are being exhausted, the land that is suitable for crops cannot produce enough food for the still growing population, and that massive famines will soon occur. These predictions are not a true reckoning of the limits of the earth, because the future productivity of the economy is not foreordained by space, energy, and cropland. It will be determined by the abilities of human beings. It has been so in the past and there are no compelling reasons why it will not be so in the years to come.

Theodore W. Schultz, Investing in People: The Economics of Population Quality (1981), p. 140.