Today, roughly a quarter of all human disease and death in the world can be attributed to what the World Health Organization (WHO) broadly defines as environmental factors. These include unsafe drinking water, poor sanitation and hygiene, indoor and outdoor air pollution, workplace hazards, industrial accidents, automobile accidents, climate change, poor land use practices and poor natural resource management.

The contribution of environmental factors to the burden of disease will be magnified and increased with the growing health-related impacts of climate change. These include shifting patterns of disease, water and food insecurity, vulnerable shelter and human settlements, extreme climate events, heat related illness and population migration.

The health sector has a key role to play in reducing its own ecological footprint, while promoting public environmental health.