Green vision: the search for the ideal eco-city

If we want to be “greener”, we should live in cities.

This statement may seem counterintuitive. But in developed countries, and increasingly in emerging markets, city dwellers are able to be more environmentally friendly than those in the countryside, because of the concentration of people, vital infrastructure and amenities, and the efficiencies that this proximity brings.

As scientists call for urgent reductions in greenhouse gases to stave off climate change, cities could play a vital role in cutting carbon dioxide while remaining the engines of the economy that they are in any industrialised society.

This is good news, because since 2007, people living in cities have outnumbered those who live in rural areas for the first time in history. The world’s population is currently more than 6.8bn, and will exceed 9bn by 2050, according to United Nations estimates. Most of those additional people will be born in cities.

Which is why architects and engineers have been pioneering a concept intended to reduce emissions while providing the homes and services needed to house all these people. “There is scope for building new cities from scratch, and we’ve seen several moves towards that in China,” says Susan Claris, associate director at Arup, the engineering consultancy.

These “eco-cities” should – according to their planners – have none of the negative effects of existing urbanisation, but should rather be environmentally neutral, or even positive.

Designers have concentrated on four key areas: energy, water, waste and transport. According to the Clinton Climate Initiative and the US Green Building Council, which have jointly embarked on a programme to support “climate positive” cities, the key requirements of an eco-city are: a self-contained economy; 100 per cent carbon-neutral energy production; an interconnected transport system and land-use pattern that shifts people from cars to walking, cycling and public transport; a zero-waste management system; resource conservation, including maximising water and energy efficiency and preserving open land, wildlife and plant habitats; and using environmentally sound building materials, preferably locally sourced.

In practice, according to Beth Ambrose, senior consultant at Jones Lang LaSalle, the property specialist, that means the use of a variety of new and old technologies, from solar panels and wind turbines to recycling facilities and incinerators to produce energy from rubbish.

One key consideration is the water supply. David Schofield, associate director at Arup, notes that only if a city has a sustainable water supply can it be counted as environmentally sound. In some countries where water is scarce, that could mean choosing a coastal site and installing a desalination plant. These tend to be energy hungry, so a renewable energy infrastructure that can power the process would be vital.

Using water efficiently also means treating sewage and recycling dirty water into a drinkable form, he adds.

Green roofs – a layer of soil and vegetation on top of a standard roof – can help with this, notes Ambrose, as they reduce run-off and allow rainwater to be captured and reused.

Green spaces are also important, she says, providing areas for people to relax and transport corridors for walkers and cyclists. One of the luxuries of setting up a new city from scratch, adds Arup’s Claris, is that planners can “design out” journeys by creating mixed-use developments, where residential areas are close to offices, factories, shops, healthcare facilities, schools and other amenities. This is the opposite of the way many modern cities in the developed world have grown, where residents may live miles away from where they work and take their leisure, necessitating long commutes by car.

Another key consideration for eco-cities, which will only increase in importance, is food security, says Claris. “Cities that rely on food being imported over long distances could find that it is expensive and leaves them vulnerable to shortages,” she warns. One way of helping to avoid food crunches would be to encourage urban gardening and ensure that there are areas on the outskirts of cities for crop growing.

As eco-city projects pass through their planning stages, says Schofield, the most important thing to remember is that all of them are different, and that the way the city is planned and developed will depend on the characteristics of the site. “There is no single simple fix,” he warns. “It is all about coming up with a bespoke solution for each city.”

While dozens of organisations have set out their theories on eco-cities, building them in the real world has not proved easy. In China, a much-vaunted project to construct an eco-city in Dongtan has stalled. Arup delivered its master plan on how to build it in 2006, but little has been done since then. In India, a project to build the Mahindra World City as an eco-city looks increasingly unlikely to qualify for that label. Other mooted projects around the world have yet to make it off the drawing board.

When it comes to building eco-cities from scratch, Masdar City in Abu Dhabi looks to be one of the most promising. Its backers aim to make it “the world’s first carbon-neutral, zero-waste city” and are pouring $22bn into the project, much of which will be focused on clean energy.

But the emphasis on building new eco-cities from scratch may be misplaced, says Claris. “Existing cities are going to grow and evolve,” she notes. “We need to have a plan for that.”

Ted Bardacke, senior associate at Global Green USA, which is engaged in ensuring that the rebuilding of New Orleans after Hurricane Katrina is done in an environmentally responsible fashion, agrees. He points out that building new eco-cities does not result in a net fall in greenhouse gas emissions – it is at best neutral, though more likely to result in a rise in emissions because of the effects of making the building materials used in the construction.

“There is only a net reduction in emissions if you also retrofit existing places,” Bardacke says.

Projects to redevelop towns across the world include Helsinki and Amsterdam in Europe, and Destiny, Florida, and Treasure Island, San Francisco, in the US. There are also projects in China, South Africa and South America.

“Retrofitting is a huge challenge, but it brings many benefits, including energy security and a better quality of life for inhabitants,” says Claris.

Gordon McGranahan, of the International Institute for Environment and Development, warns that if urban planners want cities to grow in an environmentally sound fashion, they must pay attention to social issues too. A study he led of Brazil found that “many environmental problems arise because of urban inequalities – not the other way around”.

He concludes: “While proponents of eco-cities are keen to advocate inclusiveness and equity, they are inclined to assume that if you get the eco right, the equity will follow. This seems highly unlikely.

“In practice, unless both are taken seriously in their own right, neither will be achieved.”