The Sahara Desert is growing, consequently reducing food production in the area and therefore inducing poverty. But architect Magnus Larsson has an ambitious and fanciful plan to use bacteria to create a calcite wall on the desert's southern edge:
Bacillus pasteurii is commonly found in wetlands, and is able to chemically create calcite. By unleashing the bacteria on areas of the desert, sand could be solidified into sandstone within a few hours. The way Larsson proposes to do this is fill massive balloons with bacteria and station them along the Sahara's southern border, where the weight of the oncoming waves of sand would pop the balloons. The released bacteria would then quickly set up a protective wall to block future sand shifts.