Impacts on Human Health

About one billion people around the world live a tional, aesthetic and spiritual benefits; and support-
subsistence lifestyle and any loss of ecosystem pro- ing services, such as soil formation, photosynthesis
ductivity – through declines in soil fertility, drought and nutrient cycling. The maintenance of healthy
or overfishing and other factors – can rapidly ecosystems and sustaining the diversity of goods
lead to malnutrition, stunted childhood growth and and ecological services they provide is of vital
increased susceptibility to disease. importance to the lives of millions and for global
food security.
The conceptual links between broader environmen-
tal changes and human health are well under- Losses of biodiversity, such as the erosion of ge-
stood. Changes to ecosystems and their services, netic variability in a population, are often gradual
especially freshwater sources, food-producing and not seen or fully recognized until it is too late.
systems and climatic stability, have been respon- The global nature of ecosystems and of many
sible for significant adverse impacts on human biodiversity values often means the impacts of
health in the past 20 years, predominantly in poor degradation and loss are often felt across national
countries. boundaries: this means that efforts to curtail such
losses can be hampered by political and territorial
Changes in land use, invasive alien-species, many considerations.
forms of intensive animal production and the inter-
national wildlife trade can result in an increased
risk from infectious diseases.
As ecosystems are lost or degraded, their capacity
to remove harmful pollutants from the environment
is reduced. Local and sometimes global pollutant
accumulation is the result. Examples include the
accumulation of particles and gases in the air and
of microbial contaminants, inorganic chemicals,
heavy metals, radioisotopes and persistent organic
pollutants in water, soil and food. Such harmful
substances have a wide range of negative health
impacts.
Ecosystems and their associated biodiversity are
also the source of many health cures. In 2002-
2003, 80 per cent of new chemicals introduced
globally as drugs could be traced to or were
inspired by natural products. Traditional medicines
mainly derived from plants, are a staple of pri-
mary health care for a significant proportion of the
population in developing countries.
Valuing Is Vital

Ecosystems such as forests, grasslands and man-
groves provide valuable environmental services.
They include provisioning services that furnish
food, water, timber and fibre; regulating services
that affect climate, floods, disease, wastes and
Agriculture in a rain forest in Ghana, growing cassava and fruits such as bananas
and papayas.
water quality; cultural services that provide recrea-
Credit: Ron Giling/StillPictures
ECOSYSTEM MANAGEMENT 37