- The Washington Times - Monday, July 22, 2002

Nearly two decades after one of the world's most devastating famines in Africa, some scientists are pointing a finger at pollution from industrial nations as one of the causes.
However, other scientists are calling the study flawed, noting that the computer model used also predicts rainfall patterns elsewhere in the world different from the actual, observed precipitation in the period.
The starvation brought on by the 1970-85 drought that stretched from Senegal to Ethiopia captured the world's attention with searing images: skeletal mothers staring vacantly, children with bloated bellies lying in the sand, vultures lurking nearby. Before rains returned, 1.2 million people had died.
Now, a group of scientists in Australia and Canada say that drought may have been triggered by tiny particles of sulfur dioxide spewed by factories and power plants thousands of miles away in North America, Europe and Asia.
The short-lived pollution particles, known as aerosols, didn't have to travel to Africa to have an effect. Instead, they were able to alter the physics of cloud formation miles away and reduce rainfall in Africa as much as 50 percent, said the researchers, who used a computer to simulate the atmospheric conditions.
The process, known as teleconnection, continues in the atmosphere today. Some scientists suspect it may help explain the drought gripping parts of the United States, although that question has not been examined specifically.
Although pollution might affect the behavior of rain clouds, scientists stopped short of solely blaming industry effluents for the famine and starvation that wracked the region of Africa called the Sahel.
"It's more subtle than that," said atmospheric scientist Leon Rotstayn, lead author of the study on the subject.
"The Sahelian drought may be due to a combination of natural variability and atmospheric aerosols," said Mr. Rotstayn, of the Commonwealth Scientific and Industrial Research Organization, a government research agency in Australia. The group's study will be published in the August issue of the Journal of Climate.
Over the years, the disastrous lack of rainfall over the Sahel has been blamed on everything from overgrazing to El Nino. Many scientists still argue those are chief culprits.
One interesting clue: In the 1990s, rain returned to the Sahel. During the same period, emissions laws in the industrialized West reduced aerosol pollution. The scientists don't think this is a coincidence.
"Cleaner air in the future will mean greater rainfall in the region," Mr. Rotstayn said.
Some researchers say the study is intriguing but that the computer simulation is too simple to solve the mystery by itself. Teleconnection is a reasonable, but complicated, explanation, they say.
"Rotstayn focuses on an indirect effect of aerosols that is really hard to quantify," said Philip Rasch, senior scientist at the National Center for Atmospheric Research in Boulder, Colo.
Some scientists point out that the global rainfall pattern simulated by the computer model does not match up with actual rainfall observed at weather stations around the world during the drought.
For example, the real weather observations and those generated by the computer model correspond for the Sahel, Senegal and parts of Brazil, said Yogesh Sud, senior research meteorologist at NASA's Goddard Space Flight Center in Greenbelt.
"But in India and Australia, there is absolutely no match" between recorded rainfall and the simulated conditions, Mr. Sud said.

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