South Australia faces an apparent dilemma with respect to population. On the one hand, the ageing of the baby boom generation into retirement will necessitate continued growth of the working age population both to replace them in the workforce (they currently make up over 40 percent of the workforce) and to meet the costs of a doubling of the older population. On the other, environmental limits on growth are being exacerbated by the onset of climate change. This paper argues that in the short term South Australia should continue to increase its population to offset the economic and social impacts of the baby boom. However in the longer term the State should stabilise its population at around 2 million people in recognition of environmental constraints and climate change. Stopping population growth now would have dire economic and social consequences. Moreover it diverts attention away from the necessity for there to be a significant behavioural shift toward more sustainable use of resources and the environment. There is a need for a full integration of economic, social and environmental planning.