Natural Disasters: Fact or Fiction?

The movie 'Day After Tomorrow' shows health problems could result from global warming.

From the WebMD Archives

Filmmakers call loud special effects "whammies" -- and the summer blockbuster The Day After Tomorrow is reportedly a smokin', whammy fest.

In the setup, the Larson B Ice Shelf -- a large floating ice mass on the eastern side of the Antarctic Peninsula -- has shattered and separated from the continent. A series of C-chain reactions lead to the tidal waves, tornadoes, and the freeze-drying of New York City.

"The melting of the Larson B Ice Shelf really happened," Daniel A. Lashoff, PhD, science director of the National Resource Defense Council (www.NRDC.org), tells WebMD, "but the reality ends there. The Gulf Stream did not disappear."

But what if someone told you the oceans would indeed rise 3 feet? The lower end of Manhattan would be flooding every four years? According to Lashoff, this is just one of an equally horrific sequence of real whammies that could occur by the end of this century caused by the slow simmering of our planet.

The heat-trapping property of gases (water vapor, carbon dioxide, and other gases) traps some of the outgoing energy from the earth, retaining heat somewhat like the glass panels of a greenhouse.

Jonathan Patz, assistant professor in the department of Health Sciences, at the Johns Hopkins University in Baltimore, Md., published an editorial in the British Medical Journal (May 29, 2004) outlining the health impacts of global warming.

The theory put forth in the movie, that the melting of Greenland's glaciers stops the Gulf Stream and leads to an instant ice age, he tells WebMD, is one that scientists have put forth, although it is considered very unlikely.

However, the idea of abrupt climate change -- and accompanying human ills -- is not fiction, Patz says. Cases in point:

  • Last year's devastating heat wave that killed 15,000 people in France.
  • The heat wave that killed 600 in Chicago in the mid1990s.
  • Various severe weather events: heat, droughts, floods, and storms that have killed 123,000 people a year since 1972.
  • The Dust Bowl drought that devastated America during the Great Depression.
  • Loss of wetlands in Louisiana and Florida that can wipe out species and stop production of seafood.

One does not have to go back to the dawn of time when dinosaurs were clomping around to chart noticeable changes in the weather and climate. Now there are RCCEs -- Rapid Climate Change Events. Seemingly slight changes called "forcings" -- even a 1% increase in the global temperature -- can press on the entwined ecological elements like a finger slowly pressing a light switch, as one scientist put it. At a certain point -- click! -- the climate switches abruptly to a new state. This process could lead to changes in agricultural, water, and health.

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Elements Involved

The oceans are a huge agent of change as they transport heat around the world (witness the Gulf Stream scenario). Also involved, of course, are the "cold parts," earth sections covered in ice. Ice is white and reflects 90% of the sunlight and heat away from the earth. Then, there is the atmosphere, which creates winds and transfers heat or cold to every corner of the planet.

From the atmosphere comes precipitation -- rain and snow -- which affects every growing thing. The surface of the earth also absorbs heat -- with dense vegetation soaking up 90% of the sunlight.

Patz outlines some scenarios involving these elements:

  • Warmer air evaporates water more quickly -- leading to droughts.
  • Warmer air can hold more water and when it rains, it floods.
  • Droughts lead to famine and less water for hygiene and drinking and thus more disease.
  • Floods can contaminate drinking water; and the phenomenon of contamination in areas where storm runoff and sewage are commingled is so common it even has a name: Combined Sewage Overflow events.
  • Russia and Canada already have longer growing seasons, making them more competitive in agriculture. This can have economic implications.

As we jump in our cars and run our power plants, cut down forests, and bulldoze rainforests, pave our countryside, and a huge world population breathes and clamors for food, the finger is slowly pressing on the light switch that determines the fate of the "Big Blue Ball."

This Could Make Us Sick

Patz is concerned about an increase in diseases spread by animals or insects -- but he says diseases spread by contaminated water are especially hard to control. As climate patterns change and animals and organisms come out of the rainforests, West Nile and SARS may look like a picnic.

Malaria is already being found at higher elevations, where it used to be cold enough to snuff the mosquitoes that carry it. The dreaded disease has also re-established itself in the U.S. where it had been controlled.

Every year, 500 million people, twice the population of the U.S., get malaria and up to 3 million die from it -- mainly children. Mosquitoes love hot, wet places.

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Dengue fever, also spread by mosquitoes, also basks in the warming trend. "Mosquitoes bite more frequently at higher temperatures," Patz notes, "but do not survive as long." Good to know, except, he says, there has been no demonstrable decrease in mosquitoes.

Allergies may become more troublesome. As our atmosphere becomes clogged with carbon dioxide, plants are responding by putting out more allergens. The CO2 in the atmosphere fertilizes plants and make ragweed grow faster and contain more pollen. The spring and fall pollen season, Patz says, could even run together and create a synergy between pollen and summer-loads of CO2 that could be an invitation to asthma attacks.

A recent Harvard study showed that the rising greenhouse gas levels may be contributing to expanding rates of asthma in U.S. cities and worsening allergies in millions of urban and suburban people.

Other epidemics we may have to deal with:

  • Hantaviruses spread by extra litters of rats and mice able to get in because of warm conditions.
  • Leptospirosis -- another rodent-centered disease, increasingly turning up in cities. La Nina rains brought this charmer to Central American and Columbia.
  • Plague -- yes, that plague, which turned up in India in 1994 during a terrible heat wave that drove fleas off heat-killed dead animals into houses. It's back -- and even in the U.S.
  • Cholera -- a disease characterized by severe diarrhea that took many lives in the 1990s and killed tourism in some areas of South America.

"We are changing the chemistry of the air and in the process, altering the heat budget of the world," writes Paul R. Epstein, MD, MPH, associate director of the Center for Health and the Global Environment at Harvard University, writing in Consequences: The Nature and Implications of Environmental Change.

But then Epstein adds:

"Fortunately, consciousness and values can change even more rapidly than the natural systems we all depend upon."

Lashoff agrees: "There is still time to get ahead of the problem. The major threats are power plants and cars."

But first -- bring on the whammies! Fiction can be so comforting.

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Star Lawrence is a medical journalist based in the Phoenix, Ariz., area.

Published May 28, 2004.

WebMD Feature Reviewed by Brunilda Nazario, MD on May 28, 2004

Sources

SOURCES: Daniel A. Lashoff, PhD, science director, the National Resource Defense Council, Washington. Jonathan Patz, assistant professor, department of health sciences, Johns Hopkins University, Baltimore, Md. "Climate, ecology, and human health," Epstein, P. Consequences, vol 3, No. 2. "Abrupt Climate Change: Inevitable Surprises," The National Academies, Report in Brief from the Committee on Abrupt Climate Change. Editorial: Global Warming, British Medical Journal; vol. 328: pp 1269-70.

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