Thomas Malthus was an English clergyman who popularized a set of ideas on population and agricultural growth in the early 19th century. Neo-Malthusianism refers to the variant forms of these ideas that have appeared in scholarly and scientific publications, shaped various kinds of policy making, and often exerted considerable influence on popular discourse over the years.

Malthus's An Essay on the Principle of Population was published anonymously in London in 1798. It challenged the optimistic writing of Enlightenment giants Godwin and Condorcet, who believed that scientific progress and refinement of social institutions would ensure enough food for all. Malthus instead pointed to “fixed laws of our nature,” specifically that “population, when unchecked, increases in a geometrical ratio … subsistence increases only in an arithmetical ratio.” Since ...