Global warming spells health warning
Atmospheric changes impact the environment in dramatic
ways such as flooding. July 17, 2000
Web posted at: 12:17 p.m. EDT (1617GMT)
By Environmental News Network staff
As the atmosphere heats up, the risks to human health pop
up like a mosquito-borne virus. From the West Nile virus that found
its way to New York last year to an epidemic of cholera, malaria and Rift
Valley fever spawned by flooding in the Horn of Africa, the evidence of
global warming on human health is everywhere, according to Paul Epstein,
associate director of the Center for Health and the Global Environment at
Harvard Medical School.
"Global warming can also threaten human well-being
profoundly, if somewhat less directly, by revising weather patterns,
particularly by pumping up the frequency and intensity of floods and
droughts and by causing rapid swings in the weather, Epstein noted in this
month's issue of Scientific American.
"As the atmosphere has warmed over the past century,
droughts in arid areas have persisted longer, and massive bursts of
precipitation have become more common. Aside from causing death by
drowning or starvation, these disasters promote by various means the
emergence, resurgence and spread of infectious diseases."
"That prospect is deeply troubling, because
infectious illness is a genie that can be very hard to put back into its
bottle," Epstein added. "It may kill fewer people in one
fell swoop than a raging flood or an extended drought, but once it takes
root in a community, it often difies eradication and can invade other
Developing countries territories that are especially
susceptible to infectious disease -- don't have the money or technology to
prevent or cure outbreaks. This shortfall has serious implications for
the rest of the world, Epstein said.
"In these days of international commerce and travel,
an infectious disorder that appears in one part of the world can quickly
become a problem continents away if the disease-causing agent, or pathogen,
finds itself in a hospitable environment," Epstein noted. Case in
point: the West Nile virus, which showed up for the first time in
North America last year.
Epstein points to three severe weather events triggered
by global warming -- floods, droughts and heat waves -- that bring with them
infectious diseases usually carried by blood-sucking, heat-loving
Mosquito-borne diseases are expected to increase because
the agents are extremely sensitive to meteorological conditions.
Diseases such as malaria, dengue fever, yellow fever and several types of
encephalitis are sounding the loudest alarms -- alarms heard all over the
Mosquitoes are notorious for carrying and spreading
Global warming has the potential to exacerbate
water-borne diseases, including cholera, which causes severe diarrhea.
Drought enhances water-borne diseases by wiping out supplies of safe
drinking water and concentrating contaminants that might otherwise remain
"Further, the lack of clean water during a drought
interferes with good hygiene and safe rehydration of those who have lost
large amounts of water because of diarrhea or fever," Epstein said.
Floods fuel water-borne illnesse in different ways,
writes Epstein. They wash sewage, fertilizer and other sources of
pathogens such as cryptosporidium into supplies of drinking water. The
concoction can mix with warm water to trigger harmful algal blooms.
Global warming isn't fully to blame for the increase in
the spread of infectious diseases, Epstein said. And there are
Preventive strategies include surveillance systems,
satellite monitoring and climate models to predict when conditions are
conducive to outbreaks, and a limit on human activities that contribute to
global warming exacerbate its effects.
"I worry that effective corrective measures will not
be instituted soon enough. Climate does not necessarily change
gradually. The multiple factors that are now destabilizing the global
climate system could cause it to jump abruptly out of its current
state," said Epstein. "At any time, the world could suddenly
become much hotter or even much colder. Such a sudden, catastrophic
change is the ultimate health risk-one that must be avoided at all
Copyright 2000, Environmental News Network,