Rooftop Gardens

"Chicago, it seems, has tapped into the Urban Heat Island Pilot Project, a push by the U.S. Environmental Protection Agency to curb rising temperatures in pavement-dominated downtowns. Those areas have been found to be 10 degrees higher than surrounding rural areas, largely because dark-colored roofing and asphalt soak up sunlight. Roof gardens, on the other hand, can reduce building temperatures and save on air conditioning; absorb pollutants such as carbon dioxide (one of the gases implicated in global warming); and filter and reduce storm-water runoff."