Designing houses for the moon should change the way we build on Earth

If we want to tackle climate change, we have to change the way we build. As anyone at the recent LafargeHolcim Forum for Sustainable Construction in Cairo will tell you, the single biggest consumer of energy in the world is the construction industry.

The UN predicts that 68% of the world's population will live in cities by 2050, and the millions of people flooding into cities around the world will need somewhere to live, places to work and infrastructure to support them. At its most basic, that means a lot more building.

The forum, a global conference held every three years and sponsored by the Swiss company, had as its headline speaker Norman Foster, a titan of the architectural profession behind some of the most dazzling and forward-looking buildings in the world.

He designed Apple Park in California, the Gherkin in London and the transformation of the Reichstag in Germany, among many, many others.

Foster spoke about a commission from the European Space Agency to design houses on the moon. He said the principles he and his architects and designers found themselves relying on — extreme efficiency, local materials such as lunar soil, prefabricated construction and so on — are the same as those we should be applying on Earth if we want to build sustainably. He was building with moondust — inspiring and exciting stuff.

As the various architects - from Christine Binswanger of Herzog & de Meuron, architects of the Turbine Hall at the Tate Modern in London, to Francis Kéré, who designed the Serpentine Pavilion last year — spoke about their work, it became clear that there is no shortage of bright ideas, and more than enough technology and know-how to build sustainably here and now.

The bigger issue is that it isn't happening fast enough or on a big enough scale to make a difference. If we're going to meet the reductions in carbon emissions necessary to stop or reverse the rise in global temperatures, something drastic has to change, not in the next 30 years, but in the next five or 10. The really urgent question is not how to build sustainably, but how to get people to actually do it.

Somehow, not the promise of profit, the urge to do good or even the threat of extinction seem to motivate the people putting up buildings and making cities.

Foster said in a panel discussion that architecture is the easy bit. What is lacking is political will. While many among the delegates saw this as a cop-out — basically shifting the blame from architects to politicians - not a soul had an alternative.

The architect's fantasy that the right building will not just bring them fame and riches but catalyse worldwide change is just that — a fantasy.

It does seem to be the case that a big part of what is needed to bring about change at the pace we need it is policy. But then again, the prevalent view seemed to be that policy change is too slow. By the time the policy wonks have fine-tuned the documents, we'll all have fried.

A brief respite from all the shoulder shrugging came in the person of the conference's surprise star: French architect Anne Lacaton, who said that one of the best ways of building is not to build at all.

As European cities have taken to demolishing the failed utopian social housing projects of the post-war era — often brutalist monstrosities that fostered misery and social dysfunction — she'd re-invented a few in Bordeaux, extending them and transforming them into bigger, better, lighter, airier dwellings without the tenants having to move out, or even pay more rent.

Her approach revolves around the principle "Never demolish, always transform". Perhaps the moondust we need is actually the buildings we already have. And a bit of imagination.

• Wood was a guest of the LefargeHolcim Foundation at the Cairo conference.