Mangus Larsson has a big idea. The young, Swedish-born architect wants to halt the marching sands of desertification, which threatens the homes and livelihoods of millions across the globe. And he wants to do it with bacteria.

His proposal, presented this week at the TEDGlobal conference in the U.K. (a gathering to promote new ideas), is to create a 6,000-kilometer-long sandstone wall that would bisect Africa east to west at the southern edge of the Sahara.

But it’s not so much a Great Wall-sized construction project as bioengineering writ large. A microorganism called Bacillus pasteurii, which is naturally occurring in wetlands, can turn loose media, such as sand or soils, into rock-solid stone in about a day by creating calcium carbonate.

“The idea is to stop the desert using the desert itself,” Larsson told BBC News.

Larsson’s plan, which has already won environmental accolades and global interest, would entail installing massive balloons filled with the bacteria at the front of moving dunes and popping the balloons once sand had engulfed them. The resulting hard structure could also provide water collection and even shelter, he noted.

The wall would work in tandem with the Great Green Wall, an idea to plant a 15-kilometer-wide swath of trees stretching 7,000 kilometers across the continent to much the same end. China also has plans for a treed wall, which would help stave off stands from the growing Gobi. 

In Ethiopia alone, desertification already costs the country at least 10 percent of the agricultural gross domestic product, according to the World Bank, and the costs are only projected to rise with climate change.

“There are many details left to explore in this story: political, practical, ethical, financial,” Larsson told BBC News. “My design is fraught with many challenges… However, it’s a beginning, it’s a vision.”

Image of a dust storm blowing sand across Western Africa courtesy of NASA