I recently visited Biosphere 2. Near the end of the guided tour, after exiting the giant atmospheric "lung" at the heart of the Biosphere system, we emerged back out into "Biosphere One" to an outdoor area set up with little 2 to 3 foot tall miniature box houses with flat roofs, capped with rooftop gardens. The guide said that this project, run by local U of A students, was showing results of cooling the spaces within these garden-topped box houses on average by 4-6 degrees.

The Eco-Roof project by Japanese firm Daiwa House Industry brought to mind that student project over at Biosphere 2.

The ACROS Fukuoka building in Japan is another application of the green roof concept
Watch this video on the Daiwa green roof project Eco-Roof.
"Eco Roof is roof-top greening system for corrugated steel roof, which is consisted of tray boards made of recycled plastic raw materials. With intention to have light-weight roof-top system, we adopted the plant sedum sarmentosum bunge, which grows with no frequent watering and maintenance. It not only lowers surface temperature of the roofs, but is an indispensable mechanism to prevent the Urban Heat Island (UHI) phenomenon in metropolitan area."

Todd Hopkinson