THE industrial pollution blamed for the ``greenhouse effect'' also may spawn clouds that reflect heat and lower world temperatures, a Yale University researcher says. Prof. Karl Turekian says the burning of fossil fuels that generates carbon dioxide and other gases blamed for rising temperatures also produces sulfur particles that could help lower temperatures.
There is some evidence that clouds that form around small particles such as sulfur particles reflect a great deal of sunlight, says Dr. Turekian, director of Yale's Center for the Study of Global Change.
Many scientists believe the ``greenhouse effect'' will cause world temperatures to rise between 3 and 8 degrees by the middle of the next century, causing drought in some areas and increased rainfall in others, Turekian says.
He says a study of airborne particles over the Pacific Ocean found industrial pollution may be as important a source of sulfur particles as the natural decay of plankton.
The decay of plankton had been regarded as the primary source of airborne sulfur particles over the ocean, Turekian says.
Clouds can cause higher temperatures by trapping heat close to the ground like a blanket or lower temperatures by reflecting the sun's rays back into space, Turekian says.
``There is some evidence that clouds made of small water droplets that form around small airborne particles reflect a great deal of sunlight, thus cooling the earth,'' he says in a statement issued Friday by Yale.
Since airborne sulfur particles are extremely fine, they ``are more likely to cause the formation of highly reflective clouds,'' says Turekian, a professor of geology and geophysics.
``I'm not saying that clouds spawned by pollution will cancel the greenhouse effect, but it could be that the earth's systems are more self-correcting than we had assumed,'' he says.
Yale researchers succeeded in tracking airborne sulfur compounds over the Pacific Ocean and determining if they were generated by plankton decay or pollution, Turekian says.
He says the researchers are now participating in a similar study tracking pollution over the Atlantic Ocean from US industries to Barbados, Bermuda, the Canary Islands and western Ireland.
``With this hemisphere-wide monitoring, we hope to evaluate the extent to which airborne particles from the continents are transported by wind to the oceans and the impact that has on cloud formation,'' Turekian says.