Recently, Royal Dutch Shell PLC received $865 million from the Canadian government for a carbon capture and storage (CCS) project. Green roofs, rooftops with plants, can capture and store carbon, according to a new study by Michigan State University in East Lansing. The technology to build green roofs already exists, and they can be created for much cheaper than a CCS project.
“The key to fighting global warming is capturing carbon from the atmosphere and storing it in new reservoirs that weren’t storing carbon before,” lead researcher Kristin Getter said. “In the whole scheme of things, green roofs are not the one answer to sequestering carbon, but they will certainly help.”
Michigan State researchers began the project by measuring the amount of carbon stored in vegetation on 12 green roofs in Michigan and Maryland. They also measured the amount of carbon stored in an experimental roof on campus. The study pointed out that roofs are “typically unused spaces” which provide a “unique opportunity to sequester carbon.”
If all the commercial and industrial rooftops in the Detroit metropolitan area had green rooftops, they would be able to sequester the amount of carbon comparable to removing over 10,000 midsized SUV or trucks off the road for a year, according to the study.
David Sailor, an engineer at Portland State University in Oregon said of the study, “Their argument is that the carbon sequestration in plant biomass should be considered one of the co-benefits of a green roof. Taken along with other co-benefits, you start to tell a very compelling story for green roofs.”
The study sited several barriers to “widespread acceptance” of green roofs in the U.S. including:
- Lack of awareness
- No technical information on how to build them
- Lack of government incentives
- Limited quantifiable data about the benefits of green roofs
Germany overcame the same barriers, the study points out. Green roofs, according to the study authors, will “likely become more common in the future. Brad Lowe, one of the study’s researchers, said, “In Stuttgart in Germany, 25 percent of all roofs there are green. It’s just normal. I think we can get to that level here.”