Original: It follows his 1798 writings , An Essay on the Principle of Population , which describes how unchecked population growth is exponential while the growth of the food supply was expected to be arithmetical , leading to a Malthusian catastrophe .
Simplified: Though Malthusianism has since come to be identified with the issue of general over-population , the original Malthusian concern was more specifically with the fear of over-population by the dependent poor !