Spatial and temporal abstraction, individual agency and aggregate trends in population dynamics

The relationship between population growth and environmental impact, whilst complex, is well established in the scientific literature (Samways, 2022) and can be understood at a number of levels of spatial and temporal abstraction -from the global and long-term to the local and short-term.At the most abstract level, the expansion of the human enterprise, of which per capita consumption and the size of our population are major components, is clearly correlated with environmental change at a planetary level.However, at lower levels of abstraction the role of population growth, as Robin Attfield (1983) has noted, may be a sufficient but not a necessary condition in environmental change, with other factors, including the particular values and social practices of a community, being significant drivers.Thus, a combination of population size and the practices and preferences of that population determine anthropogenic environmental change.Concomitantly, explaining the causal influences on population size itself is also dependent on the level of abstraction at which the argument is pitched.In this issue, Russ Hopfenberg's Perspective article, pitched at a global long-term level of abstraction, argues that it is the expansion in food availability that is the underlying determinant of human population growth.Hopfenberg shows that populations of non-human species are determined by the carrying capacity of their environment -that is, the availability of food, water, space and air, and the level of predation and disease.Whilst recognising that humankind has altered 10.