2- ecopolis now
A hundred years ago, the largest city in the world was London, with a population of 6.5 million. Today it is dwarfed by Tokyo. With barely a quarter the population of London a century ago, the Tokyo metropolitan area has since mushroomed to 35 million, propelling it to first place in the global city league table. Tokyo's phenomenal growth is largely due to a single factor: migration from the countryside to the city. It is just one of many to have overtaken London, which with a population of 7.5 million today doesn't even make the top 20.
This rural-to-urban migration can now be seen in scores of cities around the globe. And it has brought us to a pivotal moment in human history. In 1900. most people lived in the countryside, with a little over 10 percent of the world's population living in cities. From next year, the UN Population Division predicts that for the first time in history, more people will live in cities than in the country, and the biggest growth will be in "megacities," with populations over 10 million.
The meteoric growth of megacities—there are now more than 25 in total—has brought with it huge environmental and social problems. Cities occupy just two percent of the land surface of the Earth but consume three- quarters of the resources that are used up each year, expelling the half-digested remains in clouds of greenhouse gases, billions of tons of solid waste, and rivers of toxic sewage. Their inhabitants are making ruinous demands on soils and water supplies for food and on forests for timber and paper.
Returning the world's population to the countryside isn't an option. Dividing up the planet into plots of land on which we could all survive self-sufficiently would create its own natural disasters, not to mention being highly unlikely to ever happen. If we are to protect what is left of nature, and meet the demand to improve the quality of living for the world's developing nations, a new form of city living is the only option. The size of a city creates economies of scale for things such as energy generation, recycling, and public transport. It should even be possible for cities to partly feed themselves. Far from being parasites on the world, cities could hold the key to sustainable living for the world's booming population—if they are built right.
Fortunately, governments, planners, architects, and engineers are beginning to wake up to this idea, and are dreaming up new ways to green the megacities. Their approaches rely on two main principles: recycle whatever possible and remove as many cars as possible. So as well as developing energy-efficient buildings, emphasis is being placed on increasing the use of public transport and redesigning how cities are organized to integrate work and living areas into a single neighborhood, rather than separating cities into residential, commercial, and industrial zones.
The big ideas are still being defined, but many cities already have showcase1 eco-projects. For example, at the new home of Melbourne city council in Australia, hanging gardens and water fountains cool the air. wind turbines and solar cells generate up to 85 percent of the electricity used in the building, and rooftop rainwater collectors supply 70 percent of its water needs. In Berlin, Germany's new Reichstag parliament building cut its carbon dioxide emissions by 94 percent by relying on carbon-neutral vegetable oil as its energy source. In San Diego, California, garbage trucks run on methane extracted from the landfills they deliver to. In Austria, 1,500 free bicycles have been distributed across Vienna. Reykjavik in Iceland is among the pioneers of hydrogen-powered public transport, and Shanghai is subsidizing the installation of 100,000 rooftop solar panels. In Masdar, an emerging sustainable eco-city on the outskirts of Abu Dhabi in the United Arab Emirates, a modern version of the Arabian wind tower is used to cool urban plazas.
Planners and architects now agree that to improve the social and environmental condition of cities the top priority is to cut car use. They say zero-emission cars running on electricity or burning hydrogen are not enough. "Automobiles still require massive networks of streets, freeways, and parking structures to serve congested cities and far-flung suburbs," says Richard Register, founder of the nonprofit campaigning organization EcoCity Builders in Oakland, California. What is needed is a wholesale rethink of how new cities are laid out—and how existing ones expand—to minimize the need for cars in the first place. One way of achieving this is to build cities with multiple centers where people live close to their work in high-rise blocks that are also near public transport hubs. In parts of the world this is already taking shape.
While planners look at how to cut back the energy consumption of big cities, at the other end of the scale are shanty towns—organically evolved and self-built by millions of people in the developing world without a planner in sight. These shanties meet many of the ideals of eco-city designers. They are high-density but low-rise; their lanes and alleys are largely pedestrianized; and many of their inhabitants recycle waste materials from the wider city. From a purely ecological perspective, shanties and their inhabitants are a good example of the new, green urban metabolism. Despite their sanitary and security failings, they often have a social vibrancy and sound ecological status that gets lost in most planned urban environments.
So perhaps something can be taken from the chaos and decentralized spontaneity embodied in shanties, and combined with the planned infrastructure of a designed eco-city. Cities built without extensive high rises can still be dense enough to make life without a car profitable, and they can retain the economies of scale needed for the new metabolism built around efficient recycling of everything from sewage to sandwich wrappers. At the same time, they need to remain flexible enough for people to adapt them to the way they want to live.
