Where did Malthus’s math go wrong? Looking at the first of his curves, we already saw that population growth needn’t increase in a geometric ratio indefinitely, because when people get richer and more of their babies survive, they have fewer babies (see also figure 10-1). Conversely, famines don’t reduce population growth for long. They disproportionately kill children and the elderly, and when conditions improve, the survivors quickly replenish the population.13 As Hans Rosling put it, “You can’t stop population growth by letting poor children die.”14
