The idea of greening cities is not new, but it may be approaching a renaissance.
In the 1970s, the oil crisis unleashed many things, including a visionary idea of cities becoming solar-powered, neighborhood-centric, green-roofed oases (instead of polluted, congested, soul-deadening wastelands as they were sometimes depicted).
Activist and writer Brian Tovar sees a re-emergence of the Green Cities ideal now due to the growing urgency of global warming.
Tovar thinks today's movement lacks the visionary passion of the urban planners and architects that lead the charge 30 years ago. But while today's efforts at greening cities may be more diffuse, they stand to grow stronger as more and more megacities (population above ten million) emerge.
As Tovar notes, social ecologist Murray Bookchin discovered that cities historically were the first "free spaces" giving people a novel sense of personal freedom. But Bookchin also saw the neighborhood as the "authentic unit of political life." Neighborhoods, he theorized, need to retain their local character and yet be linked in an interdependent, municipal economy.
Sounds nice, but how do we get there from here? Sustainability goals are not paramount in American cities, but they are growing in importance. Portland, Oregon continues to take the lead in SustainLane's ranking of U.S. cities because of the ground-breaking work it did through the last 20 years in creating green development policies.
Portland's bridges are famous, but its bike path network is equally important. Photo bridgepix @ flickr
To get to green, first and foremost cities must plan and regulate for smart growth, according to Roger K. Lewis in his recent Washington Post column. Number 2 on the list for cities wanting to be greener in future is to create a "fine-grained" pattern of streets to promote pedestrian and bicycle traffic and manage traffic to ensure safety and mobility.
Third, highly effective cities of the future will be those with the best transit options - bus, bike and rail. Fourth, greening the city physically (New York's PlaNYC Million Trees initiative is a good example) expands the shady canopy that reduces absorption of solar heat by buildings and helps storm water management.
In addition to the trees, cities must 5) preserve and expand interconnected networks of open spaces, 6) maximize the use of swales and rainwater collections systems for storm water, and 7) fully exploit renewable energy to generate electricity on a metropolitan scale.
All of these are very doable, but there's one other additional element that cities will need as they get on the road to green, and that's interested and involved citizens. Portland keeps topping the green city charts partly because its citizens know and our proud of being the best sustainable city and because they continue to as "interdependent neighborhoods" keep pushing the envelope for what's possible.
More from TreeHugger on green cities
::Tall Cities = Green Cities?
::America's 50 Greenest Cities: Popular Science Ranks 'Em
::Green Cities Exhibition: SocioPolis and Verdopolis
::Model Ecopolis Called Masdar
::My Other Car Is a Bright Green City
::Green Century Institute Presents: Califia Sketchbook Design Competition