Human population health: sentinel criterion of environmental sustainability

Our personal day-to-day experience of health ailments, reinforced by much recent behaviour-oriented 'health promotion' rhetoric, easily misconstrues 'health' as a local and individual-level issue. We thus fail to recognize that, over time, the health profile of a population is the real 'bottom line' indicator of the prevailing environmental and social conditions: food yields, freshwater supplies, climatic stability, natural constraints on infectious agents, social relations, and the within-population distribution of access to these environmental assets. For Homo sapiens, 'environmental sustainability' must therefore be, ultimately, about sustaining health-supporting environmental conditions. (We may worry about the biosphere 'out there', but Earth will, as ever, re-equilibrate.) Recognition of this dependence of human population health on natural environmental function will add significant additional motivation to manage Earth's environment and climate sustainably.