With the spread of the Sahara desert threatening the livelihoods of millions in Africa, architect Magnus Larsson proposes solidifying sand into a 3,700-mile wall, the BBC reports. Speaking at a conference today in England, Larsson outlined a plan to saturate sand dunes in a line stretching from Mauritania to Djibouti with a bacterium—Bacillus pasteurii—that produces calcite, a cement-like goo.
The belt of dunes thus “frozen” would provide a buffer against desertification. North African governments have proposed a “Great Green Belt” of transplanted trees as a desert hedge, and Larsson says his wall would work well with it. “It would provide physical support for the trees,” and also perhaps stay around longer. “People are so poor … they chop them down for firewood,” Larsson noted.