Global environmental change
(A WHO report on global environmental hazards to human health)
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.
Climate change and health
Climate change has a range of complex interlinkages with health. These include direct impacts, such as
temperature- related illness and death; the health impacts of extreme weather events; the effect of air pollution in the form of spores and moulds. Other impacts follow more intricate
pathways such as those that give rise to water- and food-borne diseases; vector- borne and rodent-borne diseases; or food and water shortages.
Climate change impacts will not be evenly distributed around the world. Some regions are expected to fare worse than others. Small Island States, are amongst the most vulnerable.
Many other developing countries are also not prepared for potential environmental impacts, and even less for health- related impacts.
WHO is partnering with the United Nations Development Programme (UNDP) in a new project to pilot approaches to protect health under
a changing and more variable climate, funded by the Global Environment Facility.
Ecosystems and health
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 populations current vulnerability and their future capacity to
implement adaptation measures. The links between ecosystem change and human health are seen most clearly among impoverished communities, who lack the
buffers that more affluent communities can afford.