Elephants and Sweet Potatoes to Feed Osaka's Closed-Loop Project to Mitigate Heat Island EffectsThe mayor of Osaka, Kunio Hiramatsu, announced on February 18, 2009, that the city will carry out a closed-loop project using sweet potatoes and elephants in fiscal 2009. To mitigate the urban heat island effect in summer, the city aims to green the rooftop of City Hall with sweet potato plants and use the plant vines and leaves that are usually disposed of for feeding elephants in Tennoji zoo. The elephant's dung is then used as fertilizer to grow sweet potatoes.
Japan for Sustainability, whose Web site and newsletter note lots of other creative solutions to ecological issues. I recommend it!