 Such warnings resonate with pessimism about increasing human population and its impact on the poorest people, as well as on loss of biodiversity, fresh water scarcity, overconsumption and climate change. In their controversial work The Population Bomb, Paul and Anne Ehrlich, argue that without restrictions on population growth, including the imposition of mandatory birth control, the world faced “mass starvation” in the short term (Ehrlich 1968). This prediction was not fulfilled. In a subsequent defence of their early work, the Ehrlichs declared that the most serious flaw in their original analysis “was that it was much too optimistic about the future”, and comment that “Since The Bomb was written, increases in greenhouse gas flows into the atmosphere, a consequence of the near doubling of the human population and the near tripling of global consumption, indicate that the results will likely be catastrophic climate disruption caused by greenhouse heating” (Ehrlich and Ehrlich 2009, 66). It was also in 1968 that Garrett Hardin published his much cited article on the “tragedy of the commons” arguing that common resources can always be subject to degradation and extinction in the face of the rational pursuit of self-interest. For Hardin, the increasing pressure on shared resources, and increasing pollution, are inevitable results of the fact that “there is no technical solution to the population problem” (Hardin 1968). The problem may be analysed from the perspective of the so-called  prisoner’s dilemma  (also see the entry on the  free rider problem).  Despite the pessimism of writers at the time, and the advocacy of setting limits to population growth, there was also an optimism that echoes Mill’s own view that a “stationary state” would not be one of misery and decline, but rather one in which humans could aspire to more equitable distribution of available and limited resources. This is clear not only among those who recognize limits to economic growth (Meadows et al. 1972) but also among those who champion the move to a steady state economy (Daly 1991) or at least want to see more account taken of ecology in economics (Norgaard 1994, Rees 2020).