When asked to imagine the Earth in 2040, many scientists describe a grim scenario, a landscape so bare and dry, it’s almost uninhabitable. But that’s not what Willem van Cotthem sees. “It will be a green world,” says van Cotthem, a Belgian scientist turned social entrepreneur. “Tropical fruit can grow wherever it’s warm.” You still need water, but not much. A brief splash of rain every once in a while is enough. And voilà—from sandy soil, lush gardens grow.
The secret is hydrogels, powerfully absorbent polymers that can suck up hundreds of times their weight in water.