British planning experts are heading to China to advise on building cities that do not wreck the environment.
They will address mayors on the need to avoid Los Angeles-style sprawl by building dense cities with low-carbon buildings and good public transport.
Their visit follows a report warning that the road-based US model could make climate change impossible to contain.
Europe's densely-populated cities, with strong public transport links, are held up as an example for China to follow.
The report by the Global Commission on the Economy and Climate said more than two billion extra people were expected in cities in the coming decades.
By good planning and spending a a little extra, liveable new cities could be built with low-carbon infrastructure, it said.
In China many institutions are taking the climate more seriously than before and the travelling group from Britain's Town and Country Planning Association (TCPA) will meet officials from the Chinese government's economic research agency in a workshop on low-carbon buildings.
They will also meet officials in a similar workshop in fast-growing Shenyang, which has more than six million inhabitants. On another day they will present their ideas at the national academy of China's mayors.
Several of China's major cities suffer severe traffic jams. Some of their leaders are now looking for new ideas to make cities more densely-populated, whilst the mayors of some fast-growing cities are hoping to build in a less energy-intensive way.
China also suffers a crisis of agricultural land, so high-density planning there has many benefits.
Kate Henderson, TCPA chief executive, said: 'As more and more people across the world migrate from rural to urban areas we must ensure our cities grow sustainably.
'This means delivering schools, parks and public transport alongside employment areas and housing.
'We look forward to sharing our thinking on how Garden City principles can be applied - both to creating new communities and to regenerating existing towns and cities through high quality, beautiful, climate-resilient places.'
Follow Roger on Twitter @rharrabin