Change Agent Green roofs in Nairobi save energy, water

These gardens in the sky sometimes boast trees, as well as grass and other plants, which cool the building while sucking up carbon-dioxide pollution.

By , AlertNet

Steve Smedley/AP/The Pantagraph

Kenyan architects are designing buildings with green roofs covered in vegetation to cool their interiors, conserve energy and water, and help curb greenhouse-gas emissions.