As posters in this strand explore, the rate of population growth, energy supply and traffic congestion are some of the challenges to meet when trying to build more sustainable and pleasant cities.

Among the other factors is the energy demand of the housing stock - an issue already explored by authors in our debate. Bill Dunster shows it is possible to radically reduce demand in new build. Dan Damon explores some of the problems of making radical cuts in energy use without a total redesign.

A middle way between these two scenarios, perhaps, is the 40% House project at Oxford University, which looks at how normal households in a rich industrialised nation like Britain could cut energy use by almost two thirds and increase their quality of life at the same time.

There is a talk about this project at the Energy Institute in London this coming 18 May. You can book a place by e mailing [email protected]

The oD forum is here.

Caspar Henderson