"Recently the respected German Fraunhofer Institute for Environment, Safety and Energy Technology calculated that up to 80 percent of CO2 emissions from German industry could be captured and reused by rooftop greenhouses that profitably produce crops. Fraunhofer has a joint venture with U.S. based organization Brightfarms to put CO2-capturing greenhouses on urban rooftops, and Fraunhofer is building its own facility in Duisburg." (Quoted from article)