A new study from a team of University of Maryland researchers details a plan that could prevent the Sahara Desert from expanding much further, while also making it rain in the desert with the help of wind and solar farms that could supply enough energy for the entire world “several times over,” as reported by Ars Technica.
In a study published earlier this week in the journal Science, the researchers explained why they chose the Sahara as the subject of their experiments. While the desert is clearly wide open and a good source of solar energy, Ars Technica noted that the climate in the region is quite sensitive to “nudges,” or small changes to the atmosphere that could bring about drastic changes in the weather.
With previous research having proven that solar farms and the wind could have an effect on the weather in an area, the researchers set out to the Sahara Desert and created a “supersized” climate model where they simulated what would happen if three terawatts of wind power and 79 terawatts of solar farms were taken into account. According to Ars Technica, both figures represent a greater value than the amount of wind and solar energy that is currently being used on a global level, with the latter figure being more than four times the 18 terawatts worth of energy the world is using.
Separately, NPR wrote that the researchers’ climate model represents a broader plan to reverse the Sahara Desert’s current course, which has the area gradually expanding due to a phenomenon called desertification. This involves green vegetation vanishing from an area and the light-colored dirt that is left behind reflecting additional sun on the land, cooling the surface, but preventing it from raining by reducing the heat that sends the air upward into the atmosphere for precipitation. With less rain, even more vegetation disappears, thus leading to a “vicious cycle” of sorts.
“It occurred to me that the same [cycle] would go in the opposite way, so it would increase precipitation, and vegetation, and then more precipitation,” University of Maryland atmospheric scientist and study co-author Eugenia Kalnay told NPR.
A massive renewable energy installation in the Sahara desert would generate over 4x the amount of energy the world currently uses annually. It could also turn the desert green... ????➡????https://t.co/JV19DJ2Sc4— UN Environment (@UNEnvironment) September 9, 2018
After Kalnay and her colleagues tested the model, they discovered that the wind farms had a more pronounced impact on the Sahara Desert’s climate despite taking only a small percentage of the total energy used. Based on the results generated by the climate model, the Sahara’s temperature could increase by about 2 degrees Celsius as a result of the wind farms. Most tellingly, however, the results suggested that precipitation in the area was doubled with just the wind farms active, and still increased even if only the solar farms were used. In the latter scenario, temperatures warmed by close to 1 degree Celsius, while rainfall in the Sahara increased by about 50 percent.
All in all, the wind and solar farms combined to increase temperatures in the Sahara Desert by 2.7 degrees Celsius and increase rainfall by 150 percent, as shown on the model. The researchers also ran the model on the neighboring Sahel desert, revealing a similar increase in precipitation but a slight decrease in temperatures.
Although the results of the climate model test suggested that there’s still a lot of work that needs to be done to truly prevent the Sahara Desert from expanding, the researchers noted that the changes observed in the Sahel were significant enough “to have major ecological, environmental, and societal impacts” on the area. Likewise, Ars Technica pointed out another issue with the model, noting that there are many logistical problems that could make the actual use of solar panels and wind farms impractical and that the influence of solar panels could decrease over time as they become more effective.