Where do we go from here?

London is a huge and unsustainable organism. But can architects help change it? Yes, says Marco Goldschmied, the president of Riba, by taking a more cultural and ethical role, while below, anthropologist Herbie Girardet argues that they must learn to change their priorities.

"The simple fact is that to sustain London as a model for living you'd need a planet three times the size we've got," says Marco Goldschmied. The president of the Royal Institute of British Architects and chairman of the Richard Rogers Partnership, the country's most glamorous practice, believes that architects can make a crucial difference to the way London must develop as an organism.

He makes his case warily in a languid version of the Jonathan Ross manner, island-hopping from one idea to another, magic marker in hand, while eights scull with the tide on the Thames beyond the Hammersmith-based partnership's boardroom windows. But his message is that "architecture is an agent of change; architects should be a fifth-column that must, at all costs, insinuate the concept of sustainability into the mindsets of both legislators and the public".

The road to metropolitan excess and clumsy expedience was already well-established more than a century ago. Mr Goldschmied cites the experience of his grandfather, who was apprenticed as an engineer at Victoria in 1889. "He watched the demolition of John Nash's Regency circus at Piccadilly and the creation of Shaftsbury Avenue. And why? Because of the horse manure arising from traffic congestion. It was a foot deep in Regent Street. And you think, crikey, someone I knew saw that,"says Mr Goldschmied.

The influence of the architect in society is rarely noted "and certainly hasn't been over the last 25 years. But it's a cultural and ethical role, beyond that of simply making money for a land speculator".

And then he makes a scatter-shot of points: architects must challenge their briefs - "there's even an EU directive saying architects should do this". His enthusiasm for this seems surprising: why should any architect have to be instructed to ask questions of a client? Perhaps the key purpose of the directive is to stitch up another layer of contract-dispute legalities; it may therefore contribute little to the cutting edge.

Euro-nannying aside, architects have to be more demanding, and Mr Goldschmied - "I'm grinding an axe for the common good" - makes the analogy of "the barrister's duty to the court in relation to truth that goes beyond the needs of his client". The truth about architects, he says, is that they are problem solvers: "They juggle apples, oranges and mackerel, so to speak."

And they have to confront prejudices - not least in the case of high-rise buildings. "The obsession in England that high is bad means that you squash down buildings." The environmental effects - his felt-tip is suddenly squinching the outline of a multi-storey building on the wall - are multifarious: less light penetration, poorer ventilation, excessive heat that has to be dissipated, therefore more powerful, energy-wasting extractors.

So what can be done? "I can talk to the Parliamentary committee on the built environment and get legislation passed. People follow legislation and not much else." And, there, he gives the game away: regardless of EU directives and outbreaks of architectural innovation there will be no distinct and widespread move towards a detailed, environment-smart architecture in the foreseeable future.

Not that there has been much evidence to suggest that there would. Despite interesting and useful work by organisations including the Building Research Establishment, the plain fact is that building regulations continue to fudge even basic issues such as the minimum heat-retention standards of new buildings; contractors and developers, particularly those with shareholders, are no doubt thoroughly relieved.

Mr Goldschmied believes that the way forward is through successful example, and this is beyond dispute; legislation follows precedent. In the case of Riba, the train is already en route: an environmental audit of the institute's listed London headquarters at 66 Portland Place has been ordered to maximise its sustainable capabilities. "That will probably involve windmills on the roof - it would make a nice counterpoint to the radio antennae on the roof of the Chinese embassy opposite," he says. And, relishing the idea of "blue-sky proposals for change", he sees no reason why there shouldn't also be an urban farm on the flat roof of number 66.

The thought energises him. "If it was successful it would provide a precedent for legislation. It could be that we're on the brink of another transformation in terms of what is visually acceptable," says Mr Goldschmied. "If windmills on the roof put power-station workers out of work - tough... we're seeking to prototype the sustainability of existing buildings."

This is a key point. If architects are to make any significant difference to the environmental efficiency of buildings, they will have to think mainly in terms of the built environment rather than new buildings. The Government's Urban Task Force estimates that 90 per cent of buildings standing today will still be standing in 2030. Change, Mr Goldschmied admits, will be slow.

But he insists that what happens to buildings in London is important because changes will be seen as models of architectural development in the rest of the world. And there have been downsides in the past: "The mayor of Taipei said that traffic jams were a symbol of success. There's a mindset for you. They look to the US and Europe for solutions and cultural models."

Some of the key historic hand-me-downs, he says, have been utterly pernicious. The creation of London's suburban metroland, which originally radiated outwards from tube stops, was copied in America. "The long-term legacy of that is that, in some states, they spend more on school buses than on education."

Mr Goldschmied's whistle-stop tour through the forces that would increasingly inform architecture - dot.commery, rationalised distribution leading to less traffic, tax issues, energy offsets - is an ideas parts-list which can be seen as confetti thrown into the void or a useful grist. When pressed to predict how the capital might look and feel in 2030, he took the visionary option. "Could London be the city of windmills?" he wonders. "Could it be a city of silence?"