The quest to transform a desert

As with any desert, forecasts for the African Sahara — a giant desert roughly the size of the United States — don’t typically include rain.

With a twist of irony, that could change, thanks to technology’s harnessing of the sun.

The Sahara (which means “desert” in Arabic) is home to more than 2 million nomadic people struggling to grow food. A new climate-modeling study, reported in the journal Science, is among the first to measure the effects of wind and solar installations, and how vegetation responds. The University of Illinois researchers suggest that windmills and solar panels could help change the face of the Sahara by harnessing the sun’s energy.

As described in Smithsonian magazine, the Sahara’s few pockets of dark vegetation act as a cloak, absorbing sunlight and warming the ground beneath. Nearby areas of pale sand reflect the sun’s rays, leaving that ground relatively cooler and driving hot air upward to wrest moisture from the atmosphere. That moisture condenses and falls back to the earth as rain.

Such oases are few and farther between; the desert is expanding. The increasing barrenness and associated decimation of plant life further reduces that desperately needed precipitation.

So scientists are getting creative. The UI researchers proposed covering 20 percent of the Sahara with solar panels, which would convert the sun’s rays into energy, absorbing sunlight like vegetation does. The adjacent warmer earth could then push warm air skyward and encourage rainfall, they wrote.

An arsenal of wind farms could act similarly. Concentrating spinning turbines in one area could send air masses upward, encouraging rain cloud formation. Both would be meant to improve vegetation growth, which would continue the moisture-encouraging cycle. According to the study, reintroducing plants could increase rainfall up to 80 percent in some areas.

Such installations would also produce a lot of clean energy. The wind and solar farms simulated in the study would cover more than 9 million square kilometers and generate, on average, about 3 terawatts and 79 terawatts of electrical power, respectively.

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Sholeh Patrick is a columnist for the Hagadone News Network. Contact: Sholeh@cdapress.com