The mega-cities of North Asia are troubled by air pollution, monsoonal flooding and run-off and lack of recreational green space. Residents worry increasingly about food security and climate change. Green roofs can assist with all these issues. The author examines the effect of public policy on the increasing number of of green roofs being installed in Seoul, Taipei and Hong Kong. She describes and photographs roof gardens on a university campus, a high school, a law firm, a domestic garage and several department stores.