Public health impacts of global climate change.

The potential health impacts of climate change are wide-ranging, from direct impacts at familiar local scales, through indirect effects occurring at the regional or ecosystem level, to long term effects on the sustainability of global systems. To assess these potential impacts, there is a need to broaden the scope of health impact assessment. Eco-epidemiology is emerging as a response to this need. Eco-epidemiology entails a shift in focus: from direct (toxicological) to indirect (ecological) mechanisms; and from effects occurring at 'human' temporal and geographical scales to those at regional and geophysical scales. We discuss the potential health impacts of climate change on each scale. At the global scale, interactions and feedbacks between systems are critical determinants of long term outcomes. From an eco-epidemiological perspective, the study of climate change becomes inseparable from the study of global change more generally.