I came upon this little blurb about green roofs in the paper edition of the University of Toronto Magazine.
"Green" roofs made of an infrastructure that support soil and plants are better than conventional roofs at keeping homes cool in summer, according to preliminary results from a U of T study. Professor Brad Bass of the Institute for Environmental Studies at U of T and Environment Canada's Adaptation and Impacts Research Group, along with colleagues at the National Research Council's Institute for Research in Construction, created an experimental roof - half of it a traditional flat roof, the other half a six-inch layer of soil and wildflowers above a special drainage layer and a root-repellent, waterproof memrane. The green roof maintained a cooler surfact and interior temperature in summer and reduced storm water run-off. "The green roof acts as insulation," says Bass. "The vegetation on the roof also provides shade and returns moisture back to the atmosphere, preventing a dsignificant amount of solar energy from being absorbed by the roof."
This sounds like a far nicer solution than air conditioning, and green roofs have other benefits, too, like improving air quality, providing habitat for birds, and adding beauty.
University of Toronto green roof links:
University plans another green roof
Green roofs cool for summer, environmentalist says
Other green roof links:
Exploring the ecology of organic greenroof architecture - greenroofs.com
GreenRoofs.org
Maintenance of Green Roofs - lid-stormwater.net
Green Roofs - greenroof.co.uk
A National Research Council Canada study evaluates green roof systems' thermal performances - professionalroofing.net
Making green roofs simple - edcmag.com
Extensive green roofs - wbdg.org
Still more links (added during page update)
Northwest EcoBuilding Guild's Green Roof Project - hadj.net
Green roof workshop held in Vancouver - nrc-cnrc.gc.ca
City Farmer's green roof - cityfarmer.org
Green roof research at BCIT - bcit.ca
Green Roof Benefits - roofmeadow.com
Penn State Center for Green Roof Research - psu.edu
A green roof for our cob shed - City Farmer page at mac.com
Sky Gardens - Vancouver Courier artcicle
Rooftops and Urban Agriculture (lots of links!) - cityfarmer.org