Since 2010 Green Roofs in Copenhagen have become integrated in different guidelines such as the guidelines for Sustainability in constructions and Civil works, which mandates green roofs for all the Municipalities buildings. Green roofs are also a part of the city’s Strategy for Biodiversity. Today the City of Copenhagen has more than 40 green roofs, estimated to be a total of 200,000 square metres throughout the city. Among the rest, green roofs can absorb between 50 and 80% of the annual rainfall, and also contribute to reducing the temperature in buildings during the summer.