Mater et Magistra §186

¹⁸⁶ As a world problem, the case is put thus: According to sufficiently reliable statistics the next few decades will see a very great increase in human population, whereas economic development will proceed at a slower rate. Hence, we are told, if nothing is done to check this rise in population, the world will be faced in the not too distant future with an increasing shortage in the necessities of life.