In 2008 Copenhagen Municipality implemented a Green-Roof policy programme to tackle challenges such as impacts of climate change, increasing density and the need for healthier neighbourhoods. Green roofs are unique combinations of technical installations and ecosystems enabling cities to benefit from green areas without reducing development sites.  Green roofs cool cities, enhance biodiversity and reduce rainwater run-off. They also beautify grey and anonymous places. By involving local communities in implementation, green roofs may become communication platforms for residents of all ages and origins. By 2010, Copenhagen Municipality has integrated the establishment of green roofs in most local plans, aiming to realize about 200,000 m² of green roofs in years to come. Green roofs are aimed to be realised at all scales of buildings; from cycle shelters, schools and mixed used buildings to underground garages.