Hurricanes. Mosquitos. E. coli. Drought. Coincidence? Some scientists don't think so. Rather, they say, the dried, drenched, and infested summer of '99 may be a perfect example of how pollution is changing our climate and the climate, in turn, is affecting our health. Consider the conditions that spawned the city's unprecedented St. Louis encephalitis outbreak very dry heat followed by heavy rainfall. Both are typical of the increasingly extreme and erratic weather now attributed to the atmospheric accumulation of so-called greenhouse gases, including carbon and other industrial byproducts. The gases trap heat and create global warming, which, oddly enough, can also cause unusually cold as well as warm weather.
Few dispute the global warming phenomenon. Even the federal Environmental Protection Agency recognizes that powering factories, heating homes and businesses, and running trucks and cars has changed the balance of the atmosphere. And global warming is now widely noted for its frequent and intense weather events, including flash floods and longer droughts, all of which have become more common since the 1970s.
There is also little question that the recent weather weirdness has taken a toll: Thirty-four New Yorkers died of the heat this summer. (July was the hottest on record.) The E. coli outbreak upstate, which was traced to a violent thunderstorm that flushed cow manure into drinking water, killed two and sickened more than 900. Three people have died of encephalitis. (And malathion, one of the pesticides being used to combat the disease, comes with its own health risks.)
Yet, some experts resist tying this summer's health problems to pollution-related climate change. "It's too simplistic," says Duane Gubler, director of vector-borne infectious diseases for the Centers for Disease Control and Prevention. Gubler points out that the emergence of the St. Louis encephalitis virus usually involves the complex migratory patterns of birds and a many-year disease cycle that is not well understood.
The connection between health crises and pollution seems obvious to others, however. Paul R. Epstein, associate director of the Center for Health and the Global Environment at Harvard Medical School, stops short of directly blaming any single health event on pollution-related weather shifts. But, taken together, he says the recent health problems are consistent with the predictions about global warming. Epstein even thinks air pollution may be to blame for increasing cases of hay fever and asthma, since there is new evidence that carbon dioxide a chemical byproduct of both human life and manufacturing may contribute to these respiratory problems by raising pollen counts.
Worse, says Michael Oppenheimer, chief scientist of the Environmental Defense Fund, "We can say with some confidence that these kinds of conditions will happen more and more and diseases like St. Louis encephalitis will become a greater threat." Indeed, the weather-health spiral is becoming fiercer over time. Global temperature has increased by about one degree since the turn of the century. But, if energy consumption continues at current levels and relies mostly on coal and oil, as it does now global temperature is expected to go up 3.6 in the next 100 years, according to a report by the Environmental Defense Fund. That could mean an additional 27 days above 90 degrees each year in New York City by the year 2100. And because heat melts snow, that in turn could mean waters surrounding the city will rise, leaving the FDR Drive and West Side Highway entirely underwater.
For city dwellers, the consequences could be worse than a sunken highway or two. "The whole climate will have changed in favor of animals, more field mice, deer, ticks, rats," predicts Dickson Despommier, professor of public health and microbiology at Columbia's Mailman School of Public Health. Despommier says the shift could increase incidents of Lyme disease and rabies, and pave the way for diseases now thought of as tropical. "Malarial mosquitos will increase, also dengue fever, yellow fever," he says ominously.
The CDC's Gubler dismisses such concerns. He insists that mosquito-borne diseases such as malaria and encephalitis pose little threat in the U.S., which has systems to keep contagion under control. New infections with encephalitis do seem to be dropping off since the city began spraying with pesticides. (The most recently confirmed case was actually contracted before the city began spraying with insecticide.) And malaria, two cases of which were recently reported in Suffolk County a few weeks ago, never expanded beyond the initial blip it made on epidemiological charts.
But for Epstein, the containment of such health problems is not enough. "The point," he says, "is that instability of the climate has biological impacts." Epstein estimates that humans would have to reduce the emission of greenhouse gases by 60 to 70 percent just to allow the system to stabilize at its current state. As that degree of reduction seems unlikely in the near future, the environment will continue to lash back.
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