Advertisement
  1. Archive

Cooler Southeast defies global warming theory

Despite fears that the planet is heating up, temperatures in the southeastern United States have actually fallen 1 degree Fahrenheit over the past 30 years, according to a federal study released Saturday. The finding contradicts the widely held notion that pollution in the atmosphere has already made temperatures start to rise.

"It's cooling and getting wetter," said George A. Maul, an oceanographer with the U.S. Commerce Department's Atlantic Oceanographic and Meteorological Laboratory in Miami. "This is quite different from what the computer models suggest should be going on with global warming."

Often-repeated theories of global warming hold that rising levels of carbon dioxide, methane and other gases are trapping heat in the atmosphere, causing the so-called greenhouse effect.

These gases result from burning fuels and other sources. Computers programmed to run complex mathematical formulas predict that if the gases continue to build up, temperatures around the world will jump roughly 3 to 8 degrees Fahrenheit over the next century.

Maul presented his findings at a meeting of the American Association for the Advancement of Science.

He said his work does not definitely prove that global warming isn't happening. The fall in temperatures "may be a factor of the difficulty of calculating global warming on a regional scale. But it should increase the debate about global warming."

Last year, Maul and colleagues produced a report showing that overall temperatures across the United States have been virtually unchanged during the past century.

Two other studies, done by other groups of researchers, suggest that around the world, temperatures have risen 1 degree in the past 100 years.

However, some critics have suggested that this rise might be partially due to increasing urbanization where the temperatures are recorded. City temperatures are higher than the surrounding countryside because of the concentration of people.

Maul's latest data show that from the turn of the century to the mid-1940s, average temperatures in the Southeast rose a half-degree. But since then, they have fallen a full degree. So over nearly a full century, temperatures have dropped half a degree.

At the same time, annual rainfall in the Southeast has increased 65 millimeters, or roughly 2{ inches, since the turn of the century.

Maul said he believes that if the heat-trapping gases continue to increase _ and nothing else changes _ then global temperatures almost certainly will increase. However, he said, too little is known about other forces that affect weather, such as ocean currents and the sun's output, to say with certainty that the planet will heat up.

Computerized predictions, known as computer models, produce widely divergent scenarios of what might happen, especially over relatively small portions of the Earth.

The weather is affected by mountains, lakes and other features on the Earth's surfaces. However, adding all of these features to the computerized calculations makes the job dauntingly complex.

Michael E. Schlesinger of the University of Illinois at Urbana-Champaign, who makes computer models, said that accurate predictions about global warming will require calculations that use 10 times finer detail. And producing a model with this much detail would require running the world's fastest supercomputer non-stop, day and night, for 40 years, he said.

YOU MIGHT ALSO LIKE

Advertisement
Advertisement