Global Warming Is Hazardous to Your Health

August 19, 1999

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HARVARD GAZETTE ARCHIVES

By William J. Cromie
Gazette Staff

Heat waves and droughts, floods and mosquitoes, warmer winters and more bugs; they all tell the same story. Earth is heating up, bad weather is increasing and so are infectious diseases.

Meteorologists said that 1996 was unusually hot; 1997 was the hottest year of the century; 1998 was even hotter. In 1999, heat waves and droughts broke records in the United States.

Mosquitoes that carry malaria and dengue fever have extended their range to higher altitudes and higher latitudes. El Niño, the child of disruptive weather, threw two of its worst tantrums in history during 1982-83, then again in 1997-98. Hurricane Mitch, which roared across Central America in 1998, spawned outbreaks of cholera, malaria, and dengue fever.

"Connections between climate and disease are not new," says Paul Epstein, associate director of the Center for Health and Global Environment at Harvard Medical School. "Climate constrains the range of many infectious diseases, and weather affects the timing and intensity of outbreaks. But the warming and severe weather during the last decade poses a profound threat, not to just one region or continent, but to health around the world."

To be sure, climate’s not the only factor to blame. International air travelers fly bacteria and viruses across oceans in hours. Overpopulation leads to unhealthy concentrations of people and to human invasions of grasslands, woodlands, and wetlands. Smokestacks and vehicle exhausts pump noxious quantities of smog- producing chemicals and other harmful pollutants into our air.

Whatever the causes — human or natural — Epstein and his colleagues propose several ways to buffer the increased burden of emerging infectious diseases. They want to keep better track of what’s going on worldwide, then link changes on sea and land to more accurate forecasts. The Agency for International Development operates a famine early warning system (FEWS) in Africa, and Epstein sees this as a model for a worldwide health early warning system (HEWS).

Here’s an example. By tracking surface changes in temperatures of the Pacific and Indian oceans and combining them with changes in vegetation detected by satellites, federal scientists claim they can forecast outbreaks of Rift Valley fever in Africa as much as five months in advance. During the 1997-98 El Niño, torrential rains precipitated a population explosion of the mosquito-borne virus that causes the fever. Nearly a thousand people and much livestock died of the disease in East Africa.

Epstein also sees new national policies and international agreements as powerful weapons against the diseases. International treaties have banned the testing of nuclear weapons in the atmosphere and the release of ozone-destroying chemicals. He is hopeful that these measures will be followed by agreements on reducing the amount of carbon dioxide and other so-called greenhouse gases into our air. Those gases, Epstein says, may or may not be the major cause of global warming, but cutting down their emission has got to produce public health benefits.

On more local levels, Epstein believes that laws, policies, taxes, and financial incentives can be used to promote pollution reduction and more cost-efficient ways to generate energy, preserve the environment, and improve health.

Everyone talks about the weather, now something may be done about it.