Former US President Bill Clinton has praised the redevelopment of south London's Elephant and Castle as a global example for sustainable growth.
The Southwark revamp was named among 16 worldwide projects which will release less carbon dioxide than they use.
Speaking at the international climate change summit in South Korea, Mr Clinton said it was "very exciting".
"I've seen the future and I think all these carbon positive buildings are it," he said.
Elephant and Castle's £1.5bn redevelopment will include the creation of a pedestrianised town centre, a market square, green spaces and thousands of new homes by 2014.
It will also involve a comprehensive tree planting programme and measures to reduce pollution from its gyratory road system.
Southwark Council hopes the area will become a "thriving urban centre", replacing its dilapidated shopping centre and five 12-storey blocks of flats.
Mr Clinton mentioned the project at the C40 climate change conference in Seoul, where leaders of the world's largest cities are meeting.
He told BBC London: "If you can do a carbon positive development that big, then no-one in the world will have any reason not to do it."
Mr Clinton added that carbon positive projects would be shown to be profitable to the developers as well as the environment.
"You can do it in most cases for the same or even less money because if you use recycled and composite materials very often they are lighter, putting less drain on the energy system, there's no reason not to do this."