The global environment

Abstract

We, the human species, have reached an unfamiliar crossroads with respect to the health risks posed by the external environment. We not only continue to face the health risks posed by long-familiar forms of environmental contamination, but now also face an emerging range of larger-scale and more systemic environmental hazards. As the sheer size and economic intensity of human endeavour, globally, has escalated in recent decades, its impact on the natural systems and processes of the global environment has increased—and, in consequence, environmental changes at that larger scale are becoming evident (Kennedy 2006).

These changes, such as global climate change, freshwater depletion, soil erosion, and the loss of species, are occurring on an unprecedented scale. They represent a weakening of Earth’s life-support systems, a weakening of the foundations of biological health and life upon which human health ultimately depends. They therefore pose current and future risks to human health. Meanwhile, the ongoing increases in interconnectedness and ‘globalization’ of economic systems, trade, food systems, cultural diffusion, human mobility, electronic communication, and the spread of infectious agents are adding further to the contemporary emergence and strengthening of macroscopic influences on population health and disease.

These human-induced ‘global environmental changes’ are thus expanding the topic scope of ‘environment and health’. Contam ination by additives (chemicals, radiation, microbes) has long been the main source of environmental risks, and it remains so in many of the world’s poorer and more vulnerable communities and populations. Meanwhile, populations everywhere are beginning to encounter this further dimension of health risk from larger-scale disruptions of environmental and ecosystem processes. Food yields, for example, are becoming less secure, and infectious disease occurrence is becoming more varied and volatile.

In essence, whereas traditional environmental hazards to human health mostly arise from the unintended addition of contaminants to air, water, soil, or food—or from excessive exposure to naturally occurring environmental factors (e.g. solar radiation)—these emerging larger-scale hazards arise from the loss of environmental attributes such as stability, productivity, regenerative and absorptive capacity. This added depth, indeed qualitative extension, to the category ‘environmental health’ necessitates some new and modified research strategies. It also requires a shift in how we think about and apply preventive strategies. Show more