Life Support: The Environment and Human Health
Chapter 1: Environment, Health, and Risk
¾ Together, global warming, population growth, habitat destruction, and resource depletion have
produced a widely acknowledged environmental crisis.
The Environmental Crisis (pg. 1-6)
geosphere, and biosphere.
¾ Between one-third and one-half of the land surface has been transformed by human action.
¾ Biologists have observed startling declines in frog populations around the world. The health and
reproductive success of amphibians is being damaged by interactions between an increase in
the intensity of ultraviolet (UV) light (because of thinning of stratospheric ozone), traces of
globally distributed toxic chemicals, competition from introduced predator species, and
infections caused by virulent fungi and bacteria.
¾ The driving forces behind environmental degradation are population growth and
Human and Ecosystem Health
¾ An ecosystem-based health perspective takes into account the health-related services that the
natural environment provides (e.g., soil production, pollination, and water cleansing) and
acknowledges the fundamental connection between an intact environment and human health.
¾ An ecosystem health stance in a non-anthropocentric, holistic worldview increasingly shared by
Health and the Environment
¾ The health effects of global change are often indirect and difficult to assess and the quality of
evidence for the health-related outcomes of global environmental change varies widely.
¾ Exposure to UV light (especially UVB) increases skin cancer and cataract formation but large
studies across geographic areas with different levels of UV exposure has not been performed.
¾ Interactions between poverty, population growth, and environmental degradation impede
sustainable economic development and worsen population health.
¾ Two recent developments have drawn renewed attention to the health risks of industrical
chemicals known as persistent, organic pollutants (POPs): the identification of medical waste as
a significant source of toxic pollution and the emergence of the health effects field of endocrine
¾ Medical-waste incineration is a major source of the dioxin and mercury released into the