The Sahara Desert is the largest “hot” desert in the world. It stretches over 3.5 million square miles but is populated with only about 2.5 million people, the vast majority of whom are huddled around the oases that dot the expanse. However, the Sahara was not always a desert. Sometime around 9,000 years ago, due to a wobble in the earth’s gravitational axis, the Sahara was bathed in the rains of the West African Monsoon, resulting in a much greener Sahara, capable of supporting herds of animals now only found in the rock art left over from that time. Then, around 5,000 years ago, the wobble corrected itself and the Sahara again became the desert it is today. This proposal is based around an ambitious ecological geo-engineering scheme to “Re-Green” the Sahara as a means to open up new lands for human habitation, while actively using this project to alleviate the effects of climate change on the environment, and providing sustainable energy to the people taking advantage of these newly available lands.
In a study published in the journal Nature on 30th March, 2016, the authors state that manmade climate change could cause the West Antarctic Ice Sheet to melt, thus causing the ocean levels to rise by more than a meter by 2100. This proposal offers a potential outlet for rising ocean levels, while at the same time providing vast quantities of fresh water and sustainable energy to the residents of the North African countries that comprise the Sahara.
During the late 19th century, in the wake of the success of the Suez Canal in Egypt, a number of British and French engineers proposed the creation of a “Sahara Sea”, a vast inland sea to facilitate trade into the interior. This would be accomplished with the relatively simple trick of cutting a canal from the Atlantic Ocean or the Mediterranean Sea to one of the many depressions within the Sahara that are below sea level. However, these projects were abandoned after it became apparent that the areas below sea level were nowhere near as extensive as previously believed and the stated goals of such an undertaking were not of much interest to potential sponsors.
Then, in the 1950s, the concept was revived, specifically focusing on the Qattara Depression in western Egypt. The Qattara Depression is roughly 7,570 square miles, or slightly larger than the surface area of Lake Ontario. If the Qattara Depression were to be flooded, it would become one of the 15 largest lakes by volume in the world, containing more water than Lake Erie. The Qattara Depression is only about 50 miles from the Mediterranean Sea. The project was proposed as a civil engineering project to provide hydroelectricity for the populace of Egypt, to supplement the energy derived from Aswan High Dam on the Nile River. Due to the intense dry heat of the Sahara’s desert climate, water entering the depression would evaporate quickly, allowing water to flow almost continuously into the depression. This would quickly transform the depression into a hypersaline lake. This project was also abandoned, due to it being too expensive to dig the canal from the Mediterranean to the depression, even though President Eisenhower did consider using nuclear weapons to blast a tunnel through the bedrock.
In retrospect, it is quite fortunate that these Sahara Sea projects never came to fruition, as they would have wreaked environmental chaos on the Sahara. Below the Sahara Desert are two enormous aquifer systems. The Nubian Sandstone Aquifer is the largest in the world. The Nubian Sandstone Aquifer and the North West Sahara Aquifer, sometimes referred to as the Bas Saharan Basin, are the source of most of the oases in the Sahara. Had any of the Sahara Sea projects succeeded, the seawater would have polluted the aquifers, rendering the Sahara’s oases undrinkable, killing off the animals and people that depend on those oases for water.
Starting in the 1980s, the Nubian Sandstone Aquifer was tapped by the Great Man-Made River Project of the government of Muammar Qaddafi of Libya. The “river” is not actually a river, per se, bur rather a vast system of underground pipes that brings water from the aquifer to Libyan cities close to the Mediterranean coast, like Tripoli and Benghazi. It is important to point out that the water within these aquifers is not being replenished, so if these aquifers run dry from irresponsible overuse of the water, then the end result would be the same as if the aquifers were tainted with salt water.
This proposal takes inspiration from these previous concepts and projects, but is nonetheless separate from them, as the intent behind this proposal is specifically focused on sustainably recreating habitable areas within North Africa that have since been lost to desertification. Taking advantage of the advances in technology since the Sahara Sea projects were last seriously discussed, this proposal advocates the development of a series of “Sweet Sahara Seas”, freshwater lakes fed by desalinated water from the Mediterranean and Atlantic, with the express purpose of rejuvenating the Sahara and replenishing its water sources. Using the Qattara Depression as a trial, the Sweet Sahara Seas Project (SSSP) would follow the concept of the previous the Qattara Depression project, with one crucial difference: the water taken from the Mediterranean would be desalinated before being released into the Qattara Depression. This massive source of freshwater would be essential in the replenishment of the Nubian Sandstone Aquifer, while also providing a source of hydroelectricity, as stated above. Based on the success of the Qattara Depression project, the SSSP would aim to duplicate the procedure at a number of other depressions throughout the Sahara, including: Sabkhat Ghuzayyil in Libya; Sebkha Tah and Saguia el-Hamra/ El Juf in Morocco; Shatt al Gharsah and Chott el Djerid/ Chott el Fejej in Tunisia; Sebkha de Ndrhamcha in Mauritania and; Chott Melrhir, Chott el Hodna and Chott Ech Chergui in Algeria.
Besides the enormous quantities of freshwater that these artificial lakes will contain, their presence will help to reinvigorate areas of the Sahara hundreds of miles from any of the lakes. The prodigious evaporation that will take place under the intense Sahara sun will lead to a significantly increased level of cloud cover over the Sahara, which will in turn lead to a much greater level of rainfall over the Sahara than is currently the norm. This will lead to the replenishing of the many dry or seasonal riverbeds that can be found throughout the Sahara. This increased rainfall will lead to a significant reforestation and afforestation (the creation of forests where none previously occurred) throughout the Sahara. This will have the benefit of mitigating climate change, as all of the new greenery will help to drain some excess carbon from the atmosphere and the new cloud cover will help to deflect sunlight away from the earth’s surface.
Lake Chad, located in the southwest Sahara, on the border of Chad, Niger, Nigeria and Cameroon, is at the center of the Chad Basin, an endorheic basin, a watershed with no access to the ocean. Lake Chad is a remnant of a much larger lake now referred to as Lake Mega-Chad, which would have been the largest lake on Earth, at roughly 140,000 square miles, slightly smaller than the state of Montana and almost double the size of the current largest lake in the world, Lake Superior. However, the modern Lake Chad has been rapidly shrinking in recent decades, losing 95% of its volume in a little more than 30 years at the end of the 20th century. Because of this dramatic reduction in volume, the UN has labeled Lake Chad an “ecological disaster”. Schemes to refill Lake Chad using water from another watershed has been discussed since the early 20th century, when a German engineer suggested diverting water from the Congo River in the Democratic Republic of Congo. Interbasin water transfers are nothing new, with the water of the Colorado River being diverted through the Great Basin to sustain the fields of the Imperial Valley and the city of Los Angeles, 300 miles away. Subsequently, engineers from Nigeria and Italy have put forth similar proposals, with one being committed to by the member states of the Lake Chad Basin Commission in 2008, which would take water from the Ubangi River, a tributary of the Congo River that forms part of the border between the Central African Republic and the Democratic Republic of Congo. This proposal instead advocates piping water from the newly filled artificial lakes in the northern Sahara to refill Lake Chad as well as the Bodélé Depression, a depression about 350 miles north of Lake Chad that is significantly deeper than Lake Chad, and was itself once part of Lake Mega-Chad.
One potential issue arising from the desalination process is how to deal with the brine that is the byproduct of desalination. As a means of increasing the sustainability of this proposal by transforming an undesirable output into a beneficial product, this proposal advocates using that brine in the development of low cost, sustainable energy for residents of the Sahara and Sahel. Recently, there have been several advances in the development of saltwater batteries, which uses a concentrated saline solution as its electrolyte. The batteries are nonflammable and easier to recycle than toxic lead acid or lithium-ion batteries. One of the few resources that Sahara has in abundance is sun. By combining saltwater batteries and solar panels, this proposal can provide cheap, reliable, sustainable energy to millions of families throughout Northern and Central Africa and potentially beyond, turning these North African countries into sustainable energy powerhouses.