New Pimentel Study: LIFE ON EARTH IS KILLING US
(ENN) Life on Earth is killing us concludes a Cornell University
study of population trends, climate change, increasing pollution
and emerging diseases.
An estimated 40 percent of deaths around the world can now be attributed
to various environmental factors, especially organic and chemical
pollutants, according to an article published in the October issue of
the journal BioScience.
"More and more of us are living in crowded urban ecosystems that are
ideal for the resurgence of old diseases and the development of new
diseases," said David Pimentel, professor of ecology and agricultural
sciences at Cornell and lead author of the report, titled "Ecology of
Increasing Disease: Population Growth and Environmental Degradation."
"We humans are further stressed -- and disease prevalence is worsened --
by widespread malnutrition and the unprecedented increase in air, water
and soil pollutants," he said.
Global climate change will make matters even worse for humans and
"better" for disease, the Cornell study predicts. Increased heat favors
most human diseases, as well as the diseases and pests of food crops,
and the coming century will see masses of weakened "environmental
refugees" fleeing their home areas in a desperate search for food, the
researchers said.
The disease-ecology analysis was performed by a team of 11 graduate
student researchers who gathered data from a variety of sources, such as
the World Health Organization and the U.S. Centers for Disease Control
and Prevention, as well as previous studies at Cornell and other
universities. Their findings span a planet made less habitable by human
habitation:
-- Each year, air pollutants adversely affect the health of 4 to 5
billion people worldwide. An expanding world population is burning more
fossil fuels, emitting more industrial chemicals and driving more
automobiles. The number of automobiles is increasing three times faster
than the rate of population growth.
-- The snail-borne disease schistosomiasis causes an estimated 1 million
deaths annually and is expanding its range as human activities provide
more suitable habitats in contaminated fresh water. Following
construction in 1968 of Egypt's Aswan High Dam and associated irrigation
systems, prevalence of the Schistosoma mansoni organism in humans in the
region increased from five percent to 77 percent.
-- Of the 80,000 pesticides and other chemicals in use today, 10 percent
are recognized as carcinogens. Cancer-related deaths in the United
States increased from 331,000 in 1970 to 521,000 in 1992, with as
estimated 30,000 deaths attributed to chemical exposure.
-- Smoke from indoor cooking fires that burn fuelwood and dung is
estimated to cause the death of 4 million children each year worldwide.
-- Lack of sanitary conditions contributes each year to approximately 2
billion diarrhea infections and 4 million deaths, mostly among infants
and young children in developing countries. In the United States,
inadequate sanitation accounts for 940,000 diarrhea infections and about
900 deaths each year.
-- Dengue fever, spread by mosquitoes that breed in old tires and other
water-holding junk in crowded urban environments, infects an additional
30 million to 60 million people each year.
-- Less than one percent of 500 Chinese cities have clean air.
Respiratory disease is the leading cause of death in China.
-- In China, where tobacco smoking increased from approximately 360 to
nearly 1,800 cigarettes per person per year, males smoke 98 percent of
the cigarettes. However, mortality due to lung cancer is approximately
equal in males and females.
-- Although the use of lead in U.S. gasoline declined since 1985, other
sources inject about 2 billion kilograms of lead into the atmosphere in
this country each year. An estimated 1.7 million children in the United
States have unacceptably high levels of lead in their blood.
-- Production of another gasoline component, the carcinogen benzene that
causes leukemia even at low dosages, rose from 0.5 billion kilograms in
the United States in 1950 to current levels of about 7.5 kilograms per
year.
-- The global use of agricultural pesticides rose from about 50 million
kilograms a year in 1945 to current application rates of approximately
2.5 billion kilograms per year. Most modern pesticides are more than 10
times as toxic to living organisms than those used in the 1950s. The
only chance for relief, the researchers wrote in the BioScience report,
comes from "comprehensive, fair population-control policies combined
with effective environmental management programs. Without international
cooperative efforts," they predicted, "disease prevalence will continue
its rapid rise throughout the world and will diminish the quality of
life for all humans."
For more information, contact Roger Segelken, Cornell,
(607)255-9736, email: hrs2@cornell.edu.
Pimentel's new study can be found in the most recent issue of
BioScience, vol 48, no.10. It is entitled "Ecology of Increasing
Disease: Population growth and environmental degradation."