Should we fear falling birth rates more than overpopulation?
In 1980, two American academics made a bet. Julian Simon, professor of economics at the University of Illinois, predicted that the prices of chromium, copper, nickel, tin and tungsten would fall over the coming decade. Paul Ehrlich, professor of population studies at Stanford University, predicted that prices would rise. What Simon and Ehrlich were really betting on was the future of humanity – specifically, how many souls could the good ship Earth carry without running aground? By 1980, the global population had seen a period of enormous growth: doubling between 1800 and 1930 to reach two billion people, and then doubling again to reach four billion by 1975. Every sign