Large-scale and global environmental hazards to human health include climate change , stratospheric ozone depletion, loss of biodiversity, changes in hydrological systems and the supplies of freshwater, land degradation and stresses on food-producing systems.

Appreciation of this scale and type of influence on human health requires a new perspective which focuses on ecosystems and on the recognition that the foundations of long-term good health in populations rely in great part on the continued stability and functioning of the biosphere's life-supporting systems. It also brings an appreciation of the complexity of the systems upon which we depend.

There is growing concern amongst many natural scientists that human interventions are altering the capacity of ecosystems to provide their goods (e.g. freshwater, food, pharmaceutical products, etc) and services (e.g. purification of air, water, soil, sequestration of pollutants, etc).

Ecosystem disruption can impact on health in a variety of ways and through complex pathways. These are moreover modified by a local population’s current vulnerability and their future capacity to implement adaptation measures.

Ecosystems links
- Global Terrestrial Observing System
- Millennium Ecosystem Assessment
- Convention on Biological Diversity
- United Nations Convention to Combat Desertification (UNCCD)
- WHO Water, sanitation and health site