The 11 day United Nations conference on climate change opening in Bali on 3 December will shed new light on the degree of importance that policy makers attach to public health as they seek ways to mitigate the gradual increase in the world's temperature and prepare for the consequences.

The final part (a synthesis) of the fourth assessment report of the UN Intergovernmental Panel on Climate Change (IPCC) confirms that the trend towards global warming can no longer be questioned.

“Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level,” notes the synthesis, which was released on 17 November (see www.ipcc.ch).

The chapter devoted to health issues confirms that humans are being directly exposed to climate change through new weather patterns and indirectly through alterations in water, air, and food quality and evolving ecosystems. Emerging evidence points to changes in the distribution of some vectors of infectious disease and in the seasonal distribution of some allergenic pollen species.

More specifically, the report predicts with a high degree of confidence that there will be more deaths, disease, and injury from heat waves, floods, storms, fires, and drought; greater malnutrition; higher cardiorespiratory morbidity and mortality associated with ground level ozone; …