"Green roofs are a new fashion in nature conservation, promoted enthusiastically by the wildlife campaigner Dusty Gedge, of Livingroofs.org."
"With an estimated 24,000 hectares of roof space in London alone - an area 28 times the size of Richmond Park - the potential of green roofs is clear. As brownfield sites are developed, the only direction left for wildlife in many areas is up"
Article: Independent Digital (UK) - Room at the top
Link: Livingroofs.org
Reference:
Roofscapes (Land+Living)