An article in the November 2007 issue of BioScience describes the history and summarizes the benefits and challenges of green roofs—roofs with a vegetated surface and substrate.
Although more expensive to construct than a typical roof, a green roof can reduce energy costs during a building’s lifetime and control storm-water runoff. Green roofs also provide havens for wildlife. Such structures are currently less common in the United States than in Japan and some European countries, notably Germany, and proponents urge their more widespread adoption.
The authors of the article, Erica Oberndorfer and her colleagues, argue for further research into the functioning of green roof ecosystems and into which plant species are most beneficial to include in roof plantings. The researchers note that the development of improved cost-benefit models for green roofs could spur the more widespread adoption of the technology.
A photograph of the dramatic, almost-complete green roof on the new California Academy of Sciences building in San Francisco appears on the cover of issue.