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Can Technology Change Africa's Climate?
| Article
# : |
19866 |
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Section : |
NATURAL SCIENCE
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| Issue
Date : |
5 / 1991 |
2,747 Words |
| Author
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Michael H. Glantz
Michael H. Glantz is head of the Environmental and
Societal Impacts Group at the National Center for Atmospheric
Research (NCAR) in Boulder, Colorado. |
Each time there is a prolonged, devastating drought on the African continent, new, technologically based quick-fix solutions are offered. Many people continue to believe that technology will resolve many of the environmental problems that plague the inhabitants and governments of Africa.
Although there have been severe droughts in Africa for centuries, a major difference between these earlier droughts and the more recent ones involves technological capabilities. Today, people have the know-how to alter the African landscape in ways that their ancestors could only dream about.
Most weather- and climate-modification schemes have proposed making African land arable again while compensating for the reduced productivity resulting from inadequate land management practices. While some members of the scientific community take a hopeful view of weather- and climate-modification techniques, others question whether schemes that look good in theory will work under real world conditions. Others are extremely skeptical of the potential value for making the African continent increasingly productive.
For convenience, weather- and climate-modification schemes relating to arid and semiarid lands in Africa can be divided into three categories: vegetation modification, atmospheric circulation modification, and precipitation modification.
Vegetation modification
Vegetation modification schemes are generally based on the suggestion that there are strong interactions (called feedback mechanisms) between the land's vegetative cover and atmospheric processes. It has been suggested that destruction of forested land has an adverse effect on climate at the regional and local levels. As early as the 1930s, E.B. Stebbing, a British forester, suggested that "deforestation, coupled with overuse of the land through poor land management practices, has led to a drying out of the soils." This, he suggested, led in turn to a slow but sure decline in regional annual rainfall. Stebbing was convinced that as the land deteriorated, woodlands changed to savanna, then to semiarid sahel, and finally into desert.
When Stebbing wrote these comments in the 1930s, he was concerned about the apparent shift southward of the Saharan desert sands at about a half-mile a year. Today, rates of desert encroachment to the south have been estimated at up to 30 miles a year. He spoke of
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