The world was already facing a fertilizer shortage which would have resulted in famine. That was the impetus for developing Haber-Bosh. The fact that petroleum

The world was already facing a fertilizer shortage which would have resulted in famine. That was the impetus for developing Haber-Bosh. The fact that petroleum is plentiful and cheap resulted (eventually, and in conjunction with other factors) cheap, plentiful, reliable food production no one at the time dreamed of.