Three main themes have long characterised the debate on population and the environment. These are: the neo-Malthusian argument that population growth is ‘bad’ for the environment; the Cornucopian argument (sometimes called the Nationalist, Boomster or Tech-fix argument) that population growth is ‘good’ for the environment; and the Marxian/Socialist argument that population growth is not directly related to environmental impact but that many economic and political factors intervene between the two. Common to each is the idea that population growth and its continuance are a given, and closely related are two burning questions: whether there should be less, more, or stable numbers of people, both globally and in individual countries, and whether governments should employ population and other policy interventions to achieve these objectives.

Answers to these questions are readily forthcoming – and almost always reflect the theoretical or ideological perspective(s) of their proponents. ‘Deep Green’ environmentalists, for example, tend to argue from the neo-Malthusian position, that there are too many people, and that fewer are needed if major environmental and social catastrophes are to be avoided. In contrast, business councils and related interest groups tend to argue from the Cornucopian perspective, that there are too few people, and more are needed to facilitate wealth creation and the economies of scale that would deliver less environmentally damaging practices and technologies; while those concerned with social justice tend to argue from the Marxian/Socialist, ‘Red Green’ point of view that population size is a moral and distributional issue, less to do with how many people a country should have than with the extent to which those people – and their governments – could or should alter their values and consumption habits in order to achieve a more globally equitable and sustainable future.