If the population of the world becomes sinful, demonic, then nature will not supply you sufficient food. She will diminish. We have got experience. In India we have seen, some years there is overproduction of mango. People… Very cheap. Everyone can purchase. And sometimes there is no supply, some year. Similarly, foodgrains also. Some year there is oversupply of foodgrain and sometimes there is scanty supply. Now, this supply of foodgrains, fruits, and everything, even milk… In our New Vrindaban, because the cows feel very safe, they give us sufficient milk. That is our experience. So you keep things in order according to the Vedic injunction, you get sufficient food. There is no question of scarcity. But if you become sinful, demons, then the nature's food supply will be ultimately stopped. You can produce your food in the factory… You cannot do that. You can produce motorcars to consume all the petroleum within the earth, and then you become no petrol. Then throw all these motorcars. Unless you find out some other energy That you can do. You can make things topsy-turvied. But by your so-called scientific advancement, you cannot increase or stop nonproduction. That you cannot.
From Srila Prabhupada's lecture on Srimad-Bhagavatam 1.3.14 — Los Angeles, September 19, 1972