Life, but not not as we know it

With its breakneck economic growth, soaring demand for energy and heavy dependence on coal, China is often depicted as the world's environmental bogeyman. Yet Dongtan, a ground-breaking eco-city to be built near Shanghai, is already setting new standards in sustainable urban planning and inspiring decision-makers worldwide - including London's mayor, Ken Livingstone.

Dongtan will be built just 3km from a bird sanctuary whose varied residents include the endangered black-faced spoonbill (just one thousand of these large, white wading birds are estimated to remain in the wild). And its location, in protected wetlands on Chongming Island at the mouth of the Yangtze river, doesn't exactly sound like a good starting point for an environmentally sustainable city with a population of half a million.

But Dongtan's designers insist that it's a blueprint for how cities could support, rather than destroy, the environment. For its two major goals are to generate zero carbon emissions and cut average energy demands by two thirds via a unique city layout, energy infrastructure and building design.

"Two years ago we were approached to assess the likely ecological impact of developing a city in an area adjacent to protected wetland," says Alejandro Gutierrez, design leader for Dongtan at Arup Urban Design, London. "Our belief was that there was a wonderful opportunity to build a new city that, through its design and construction, would also address a broader range of concerns, such as air quality, and energy demand."

Development of the area, which belongs to the Shanghai Industrial Investment Corporation (SIIC), an investment company owned by the Shanghai city government, was inevitable. A bridge and tunnel linking the island to Shanghai had already been approved. The question was how best to manage the development.

Dongtan will be built on an island that has grown over the past 100 years from silt dumped by the Yangtze. The Chinese government has consistently reclaimed land from the marshlands around it, but the plan is that Dongtan will be the area's last piece of development - so further silt deposits will simply increase the available natural habitat for the birds.

Inspired by Arup's assessment, SIIC asked it draw up plans for a sustainable eco-city able to balance the needs of its inhabitants and those of the natural environment, now and in the future. At the heart of Arup's blueprint is the goal that Dongtan will generate all of its energy needs from renewable sources and that zero emissions will be generated from the city's vehicles. An "energy centre", developed by Arup and the University of East Anglia's carbon reduction team, will manage energy from wind turbines, bio-fuels and recycled organic material. Most of Dongtan's waste will be reused and organic waste will be composted or used as biomass for energy production. Human sewage will be processed for irrigation and composting - there will be no landfill waste sites.

The city itself is being designed around a series of village-style neighbourhoods to make it pedestrian- rather than car-friendly. The alignment of streets will capitalise on the microclimates created by urban development, and the width and aspect of buildings will optimise the benefits of shade and direct sun to ensure efficient energy use. An integrated mix of residential, commercial and industrial areas - common in the West but unusual in China - will ensure people walk to most places they need to reach.

Technology to both generate and save energy will be integrated into buildings and all modes of transport. The emphasis is on making eco-living the norm, rather than trumpeting Dongtan's green credentials with bold - and, potentially, intimidating - statements.

"We don't want to replicate a European city in China, or create an alienating futuristic environment," says urban designer Braulio Morera, who is also working on the Arup team. "We want to reinterpret a Chinese city - and Chinese urban lifestyle - for the 21st century. Bicycles, for example, will be a major feature, as will boats, but the bikes will be powered by renewables, and the boats by hydrogen."

Dongtan's developers are also commited to returning agricultural land around the city to its original wetland state. This will create a buffer zone between the city and the marshes that will cut down the spread of pollutants to areas where the black-faced spoonbills congregate. Farmland around the city will grow food for the residents.

The current timetable is tight, to say the least. Phase one of Dongtan, a marina village with a population of 20,000, is due for completion by 2010; 80,000 people are expected to be living there by 2020. But even though construction is yet to start, the project is already causing a stir around the world.

"Very soon on our planet more people will live in cities than in the countryside," says Sir Robin Saxby, the deputy president of the UK's Institution of Engineering and Technology, which last week staged "2020 Vision", a youth conference at which latest developments from Dongtan were discussed. "Cities consume vast amounts of energy and create huge volumes of waste and greenhouse emissions. Creating cities that address these issues and work better is one of the greatest challenges we currently face."

This is a view also shared by Ken Livingstone, who last month announced plans for a zero-carbon development in London. The project, which stems from a proposal from Greenpeace, will see 1,000 zero-carbon affordable houses built in the Thames Gateway. Like Dongtan, the development will be designed by Arup.

The Thames Gateway project has, in part, evolved from Greenpeace's campaign for energy decentralisation - the generation of energy closer to where it will be used to improve efficiency and minimise wastage. "This, along with other measures such as maximising solar energy by building south-facing houses and ensuring all new houses have adequate insulation as standard, is the only way forward," Greenpeace climate and energy specialist Robin Oakley explains. "In Surrey, where Woking council tried just this on a small scale, switching to buying energy locally and making better use of renewable energy not only saved money but cut emissions from council buildings by 77 per cent."

Oakley, who ran Greenpeace China's climate-change campaign from Beijing for 18 months until last December, says it should come as no surprise that China is now taking a lead in sustainable urban development. With an estimated 300 million people expected to migrate from the Chinese countryside to its cities over the next 15 years, sustainable energy has become a major concern. "China is often held up to the rest of the world as a threat - quite often unfairly," says Oakley. "The current environmental challenges we all face aren't just down to today's rapidly industrialising nations, though - they've been caused by our own development, and many of our ongoing policies to sell these countries old, environmentally-damaging technologies."

Oakley insists that all of us are responsible for ensuring countries like China develop sustainable solutions. "Their achievements will be a crucible, proving that renewable technologies work and, ultimately, helping lower their cost for everyone."

China crisis: the country's role in global warming

* The world's largest emitter of greenhouse gases may be the USA, but China is hot on its heels. Today, China is the world's biggest producer and consumer of coal, its fastest-growing car market (by 2020 it will have 140 million private cars), and home to five of the world's 10 most polluted cities.

* The rapid rise in China's emissions is due to its huge economic growth. As its economy boomed, demand for electricity outstripped supply, causing power shortages. To combat this, China invested heavily to increase capacity. Today, 70 per cent of China's power stations are fuelled by coal.

* Due to increased investment in the power sector, some analysts are now warning that China could soon have an oversupply problem. China's government is currently trying to steer the country's economic focus away from energy-intensive activities such as heavy industry, towards services and computing.

* The Chinese government is now keen develop new energy-efficient technologies. It has recently given the go-ahead for several huge new projects to turn dirty coal into clean gas. It is also pumping billions of dollars into renewable-energy sources such as solar and wind power.

* Another recent government initiative is encouraging the use of hybrid vehicles (which use both petrol and electric motors). Last year Toyota began working with one of China's biggest car-makers, FAW, to assemble its Prius hybrid car in China and hopes to sell 3,000 units in the country this year. Volkswagen and General Motors are also exploring the viability of building hybrids with Chinese partners.

* Global warming as a result of man's actions is likely to raise temperatures on Earth by at least 3C, according to the Government's chief scientific officer, Professor Sir David King. Speaking last month he warned that, even if a global agreement could be reached on limiting greenhouse gas emissions, climate change was inevitable.