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A new study reveals that the Sahara is the largest hot desert in the world, but parts of the park could be made green if large solar and wind farms were installed there.
These researchers could increase rainfall in the Sahara, especially in the neighboring Sahelian region, a semi-arid region located south of the giant desert, researchers said in the study published online Sept. 7 in the journal Science .
"This increase in rainfall in turn leads to an increase in vegetation cover, creating a positive feedback loop," said Yan Li, research co-researcher at the University of Illinois. declaration.
Researchers already knew that wind and solar farms could increase heat and humidity in immediately adjacent areas. But this study is among the first to model how wind and solar farms will affect the Sahara, while considering how green plants and trees would respond to these changes, said Li, who began the study while a postdoctoral researcher and ocean sciences at the University of Maryland. [The 10 Biggest Deserts on Earth]
"Previous modeling studies have shown that large-scale wind and solar farms can produce significant climate change on a continental scale," said Li. "But lack of vegetation feedback could make climate impacts modeled. very different from their actual behavior. "
Li and his colleagues simulated what would happen if wind and solar farms covered more than 3.4 million square miles (9 million square kilometers) of the Sahara. On average, wind farms would generate about 3 terawatts, while solar farms would produce 79 terawatts of electricity in one year, they said.
It's a lot of energy. A terawatt can power approximately 10 billion 100 watt bulbs simultaneously. "In 2017, the global energy demand was only 18 terawatts, which obviously represents a lot more energy than is currently required worldwide," Li said.
The model also showed that wind farms caused a warming of the localized air temperature.
"Nocturnal warmings are more common because wind turbines can improve vertical mixing and lower hot air," the researchers wrote in the study. According to the researchers, rain has also increased 0.25 inches (0.25 millimeters) per day on average in wind farm areas.
"It was a doubling of rainfall compared to control experiments," Li said.
The Sahel would see even more rain; an increase of 0.04 inches (1.12 mm) per day in areas with wind farms, which would help the vegetation to develop there, the researchers said. This translates into an increase of 200 to 500 mm (8 to 20 inches) of rain per year in the Sahel, so it would not be considered a desert. (Deserts, by definition, are areas that receive less than 10 inches (250 mm) of annual precipitation.)
Solar farms would also have a positive effect on temperature and precipitation, the researchers noted.
"We have found that large-scale installation of solar and wind power plants can generate more precipitation and promote vegetation growth in these areas," said Eugenia Kalnay, Distinguished Professor in the Department of Atmospheric and Oceanic Sciences of Canada. the University of Maryland, said in the statement. "The increase in precipitation is a consequence of the complex land-atmosphere interactions that occur because solar panels and wind turbines create rougher and darker land surfaces."
If this model becomes a reality, "increased rainfall and vegetation, combined with clean electricity from solar and wind energy, could help agriculture, economic development and social welfare in the Sahara, Sahel, in the Middle East and elsewhere. neighboring regions, "said Safa Motesharrei, a Systems Specialist at the University of Maryland, in the release.
"The Sahara has been developing for a few decades and the solar and wind parks could help stop the expansion of this arid region," said Russ Dickerson, a leader in air quality research and professor at the Department of Atmospheric and Oceanic Sciences of the University of Maryland who was not involved in the study, said in a statement. "It sounds like a win-win for me."
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