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Two Birds, One Stone: Fighting Desertification, Generating Renewable Energy

By Miles Bolton



The Sahara. From WikiCommons

DESERTIFICATION

Of the myriad of environmental problems being researched, desertification is one of the most troubling issues related to climate change. First defined by the French ecologist Andre Aubreville in 1949, desertification refers to the process by which once arable land is degraded and turned into desert as consequence of human induced erosion. Climate Change related weather conditions play a big role as well, which of course wasn’t as great a factor in 1949.

Desertification affects over 135 million people globally and threatens to displace populations in Africa, China, and Latin America. Africa is highly vulnerable to desertification, especially in Sub Saharan Africa as the Sahara desert continues to encroach on once productive land with the aid of prolonged drought conditions, by 2020 a predicted 60 million people are at risk of displacement due to the effects of desertification. 74% of Africa’s agricultural drylands are seriously or moderately degraded due to poor land use practices and drought conditions, placing much of Africa's drylands at risk of desertification.

Desertification doesn’t just expand the area of deserts, it alters rainfall patterns as well. After the soil is degraded by drought, the vegetation dies off, leaving behind light colored dirt which reflects a greater percentage of the sun rays. In turn, this cools the soil surface meaning less heat to drive air upward into higher and cooler levels of the atmosphere, the normal atmospheric process that leads to precipitation. Desertification essentially affects atmospheric processes, decreasing rainfall in affected areas which further accelerates the process of desertification as the Sahara (Gobi, Kalahari too) annexes more and more once green land.



Desert Sunlight Solar Farm in the Mojave Desert in California. (Photo Credit: WikiCommons)

THE SOLUTION

Eugenia Kalnay, a decorated atmospheric scientist at the University of Maryland, has been researching solutions to the problems presented by desertification over the past decade and has recently experienced a breakthrough in her research. On September 7th, 2018, Kalnay and her fellow researchers published a paper presenting a computer model demonstrating how the installation of large scale solar and wind farms in the Sahara could increase rainfall and vegetation in the region. Kalnay thinking about how desertification changes atmospheric currents wondered if there was a way to revitalize atmospheric conditions in affected areas and possibly reverse the effects of desertification. Kalnay hypothesized that solar panels could help heat up the land surface and restore rain bearing air currents then convinced one of her post doc researchers to develop a computer simulation to test out her theory. They also performed the same simulation with wind turbines, finding that they would boost these beneficial air currents as well. Wind farms increase rainfall by mixing warmer air from higher elevations, creating a feedback loop that increases processes of evaporation, precipitation, and ultimately plant growth.

The computer model envisioned a hypothetical Sahara Desert where 20% of the land was covered in solar and wind turbines, which translates to a whopping 1.8 million square km (kilometers). They specifically focused on the Southern Edge of the Sahara, known as the Sahel region, where the project would be most effective. The area is sparsely populated as well so as not to risk displacing more people. This proposed uber solar-wind farm would generate 4 times as much electricity as the entire planet consumes at the moment. Kalnay imagines the use of high capacity transmission lines to deliver the electricity to large energy markets in Europe, Africa, and the Middle East. The solar panels would reduce albedo as well, (reflectivity of suns rays) warming the land surface and resulting atmospheric currents thus triggering a positive albedo-precipitation-vegetation feedback increasing rainfall by 50%. Coupled with the role played by wind turbines in facilitating moisture laden air currents, total precipitation in the region would double (total annual rainfall increase of 20mm-500mm) and increase vegetative cover by 20%. 

A scenario that not only has tremendous environmental implications but also signigficant socioeconomic implications as one would think this massive supply of energy could greatly bolster the economic security of  African nations within the Sahel region (Mauritania, Mali, Niger, Chad, and Sudan). The Sahel region is one of the poorest regions of Africa and would greatly benefit from accessing renewable energy from this project and from having access to revegetated green pastures for farming. At this point it's difficult to extrapolate to what extent the project could encourage economic development in the region but one would think it would have a positive impact unless there were significant energy distribution disputes between nations.



Wind Farm in Tarfaya, Morocco. (Photo Credit: WikiCommons)

IS THIS TOO GOOD TO BE TRUE?

Kalnay when told her scenario sounded like science fiction on NPR she cooly responded “It would be science fiction if the technology wasn’t available”. Granted, a project of this scale would call for tons of investment and international cooperation. However Kalnay is right in that while the project would be difficult to pull off it is 100% technologically possible and if we are going to make significant strides in combating climate change we need to invest in and push game changing projects like this.

But what about the total warming effect that could be caused by reducing albedo in the area with massive solar installations? The paper estimated a near-surface air temperature increase of +2.16 Kelvins, however Dr. Li (co-author of paper) contends that while there'd be a small regional increase in temperature it's minimal when compared to reduced future global warming with the replacement of fossil fuel production with the renewable energy produced from the project.

The discovery is literally just about a week old so it's too early to say how much traction the project will gain with international bodies and investors. Kalnay, Li, and the other researchers associated with the project are confident in the far reaching benefits of the project and are keen on implementing their project in the Sahara. Time will tell and I will provide updates on the project when they materialize.

Remember "It would be science fiction if the technology wasn't available" (Kalnay)


REFERENCES

https://www.bbc.com/news/science-environment-45435593 https://www.npr.org/sections/goatsandsoda/2018/09/09/645539064/so-maybe-stopping-the-sahara-from-expanding-isn-t-an-impossible-dream https://www.thenigerianvoice.com/news/89273/current-dynamics-of-desertification-in-africa-facts-and-sta.html http://science.sciencemag.org/content/361/6406/1019 https://en.wikipedia.org/wiki/Sahara

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