Global climate change:
Which experts are getting warm?
NOW THAT THE 25th anniversary of Earth Day has come and gone, perhaps it's time to take a cool-headed look at global warming. Loudly publicized by the prophets of environmental doom, yet harshly maligned by its critics, the issue of global warming generates much heat but often little light--particularly in the mass media.
The New York Times began the year proclaiming "A Global Warming Resumed in 1994, Climate Data Showed" on its front page. Citing data from three different studies, the Times declared that "global warming, interrupted as a result of the mid-1991 eruption of Mount Pinatubo in the Philippines, has resumed-just as many experts had predicted." More recently, news stories were ripe with speculation: Could an iceberg that broke away from Antarctica be signaling the advent of global warming?
Yet in late 1994 the Reader's Digest printed a colorful graph showing temperatures had remained fairly constant over the past 15 years, well below the predictions of global warming theorists.
Readers might question the significance of data appearing in this source, but the Digest was not alone. The Futurist shouted "Apocalypse--NOT" in its January cover article, listing global warming as one of seven "doomsday myths." And The Christian Science Monitor reported that "Scientists question the global warming theory," calling it "too simplistic a concept." Presumably, the Monitor's scientists were not the same ones the Times interviewed.
For those of us without a scorecard, it's getting a little hard to follow this debate.
"Journalists often confuse science with philosophy," says Steve Ross, a professor at Columbia's Graduate School of Journalism. "Whether you believe global warming is happening now or is centuries away has less to do with science--we don't really know--than our own personal philosophy regarding political and environmental issues," he explains. Ross recommends that journalists report only what they know, not what they believe, and that they explain the limits of their knowledge.
What are the facts? According to David H. Rind, climate researcher at NASA's Goddard Institute for Space Studies in New York and adjunct professor of geological sciences at Columbia, naturally occurring greenhouse gases--mainly water and carbon dioxide (CO2)--help keep the planet warm and life-sustaining. However, by burning fossil fuels such as coal, oil, and natural gas, humans have loaded the air with additional greenhouse gases that trap and retain heat from the sun. Indeed, atmospheric concentrations of CO2 have risen from a preindustrial 280 parts per million (ppm) to the 1990 value of 353 ppm. And scientists agree that the average world temperatures have risen about a degree (0.9 degrees) Fahrenheit over the past century.
"But there's no smoking gun," adds Rind. Whether the rise in temperature can be attributed to the increased CO2 or some sort of natural climatic cycle is unknown. Computer models notwithstanding, there's no clear answer whether the rise will continue or at what rate. "Although some type of warming may be happening," says Rind, "we don't really know its magnitude; there are just too many variables."
That's not often the story you get in the popular press. Between the lurid scenarios of the global warming theorists--ice melting at the poles, rising sea levels, the end of the world as we know it--and the absolute scorn and ridicule of the skeptics, you need to be more than a weatherman to know which way the wind blows.
-- Adrienne C. Brooks
Reaction to this article by Tom Yulsman, Earth magazine, in 21stC's Winter 1996 issue
Wallace S. Broecker and Allan Mazur, "Global Warming and Consensus Formation," 21stC, Winter 1996
21stC special issue, "Biospheres," Fall 1996
Further information about Earth Day
A critique of global-warming theories by Kevin McFarlane of the Libertarian Alliance