Global environmental change and human population health: a conceptual and scientific challenge for epidemiology.

A large and rapidly growing human population, resource intensive industrial practices, and land exhausting agriculture has overloaded the carrying capacity of the planet's natural systems. Evidence of overloading include global warming, soil degradation and topsoil loss, decreasing stratospheric ozone, depletion of groundwater, reduced genetic and ecosystem diversity, and acidification of water and soils. These global environmental changes threaten human health in qualitatively different way than the way conventional environmental pollutants do. The risks arising from these changes stem from impairment of productivity (soils, forests, oceans, biodiversity) or stability (climate, sea level, ultraviolet, filtration). Epidemiologist must adopt an ecological model to identify, study, and to quantify the health effects of ecological disturbances. The health effects from these disturbances include those caused by atmospheric changes, by reduced agricultural yield, and by uncontrolled growth of urban populations. The UN recognizes that scientific disciplines and human capabilities to evaluate and provide sound guidance cannot keep pace with the fast rate of ecological change. Thus, rather than empirical evidence, interdisciplinary research, using modeling and forecasting to assess health effects, is needed to provide decision makers with the best available estimates.