14 DAY TRIAL // Engineers have recently unveiled a plan that a few years back might have seemed like a joke – to build a wall to mark the spread of the Sahara desert, so that the dunes stop spreading over yet-unaffected ground. The problem appears all over the Saharan borders, as fields and families are being displaced by the drying, sandy soil.
The 6,000-mile wall, its proponents argue, would be formed through solidifying sand dunes via the use of bacteria, and would stretch from the West African state of Mauritania, to the eastern Djibouti. The plan was proposed by Architect Magnus Larsson in Oxford, at the TED Global conference, the BBC News reports.
The idea comes on a very solid background. Since 2007, the United Nations have been known to consider desertification as “the greatest environmental challenge of our times,” because it continues unhindered, despite nations' best efforts. “The threat is desertification. My response is a sandstone wall made from solidified sand,” the expert, who describes himself as a sand dune architect, is quoted as saying. Constructing such a wall may prove not to be such a challenge as first comes to mind, he added.
Flooding marked dunes with layers and layers of specific bacteria could fix them in a matter of hours, making them as strong as concrete. The common microorganism Bacillus pasteurii can be found in most wetlands, and it has demonstrated the ability to convert sand into sandstones very fast. “It is a microorganism which chemically produces calcite – a kind of natural cement,” he shared.
“The idea is to stop the desert using the desert itself,” Mr. Larsson added at the conference. Additionally, the new structures, which could be constructed all over the 140 countries estimated to fight desertification, would also provide a solid foundation for planting trees and other forms of vegetation, which could help fix the soil even better.
“There are many details left to explore in this story: political, practical, ethical, financial. My design is fraught with many challenges. However, it's a beginning, it's a vision; if nothing else I would like this scheme to initiate a discussion,” the architect added. He also highlighted the fact that the resulting structures could potentially be excavated, and various shelters, or moist traps could be constructed inside them.