In 1989, when the environment was briefly top of the UK national agenda, a group of Chinese planners came to London. Many of the people who met them wanted to know how the country had managed to get so many citizens to ride bicycles - something the British authorities were unable to do. The Chinese were perplexed. "You don't understand", said one. "In 20 years time, no more bicycles. All cars."
That prediction is being realised. Beijing's roads, once kerb-to-kerb with bikes, are now choked with cars. In terms of traffic, noise and air pollution, Shanghai could be Lagos or Cairo.
City after Chinese city is widening its roads, building flyovers and underpasses to cater for the increasing number of cars. The fastest automobile explosion the world has ever known is underway across the world's most populous country. The bike, just a generation ago the transport of choice, is literally being driven off the street.
Last year, the Chinese reportedly bought four million new cars. Auto numbers there, says the World Bank, are now doubling roughly every four years.
Commentators suggest that the country's 1.3bn people will have more cars than the US within 25 years. Even now, the world's leading carmakers are spending billions on setting up plants, vehicle prices are dropping precipitously, and the car has become the object of the new consumer's dreams.
It is a similar story throughout the developing world. For the first time, more than one million new cars were sold in India last year, and the automobile industry there is growing at a rate of about 20% a year. The car fleets of Brazil, Indonesia, South Africa, and Nigeria are growing at similar rates.
But compared to the West, these numbers are as nothing. Private car ownership in the US is about 745 vehicles per 1,000 people, with slightly lower rates in Europe. There may be one car for every 2.4 British people, but only eight Indians and Chinese in 1,000 so far have a car.
Transport, says the Energy Saving Trust, accounts for 26% of all Britain's greenhouse gas emissions and is the fastest growing source of global emissions. While the US is by far the greatest source, figures released this month by the European Environment Agency figures show emissions are still rising in Europe, making it unlikely that EU countries, as a bloc, will meet their Kyoto target.
Transport in developing countries, however, could exceed those in the industrialised world within five years.
Three years ago, US energy secretary Spencer Abraham suggested that there would be 3.5bn motor vehicles by 2050 - almost four times as many as there are today.
Unless there is a dramatic switch away from inefficient petrol and gas-driven cars towards biofuels, hydrogen, solar and clean electric power, this growth will be an impossibility. At the simplest level, there will not be enough oil. At the moment, oil supplies and refinery capacity can only just meet world demand from 795m vehicles.
Andrew McKillop, author of The World's Final Energy Crisis, calculates that China, India and other developing countries will never be able to achieve the vehicle "saturation" ownership levels of the US.
"There is simply no prospect of China, India, Malaysia, Brazil, Turkey, Iran, Ukraine, Mexico and other emerging car producers being able to achieve US, west European, Australian or Japanese rates of car production and ownership," he says.
"At current consumption rates, the estimate of 3.5bn motor vehicles would increase world oil consumption by about 70%."
Clear the air on tyres that are about 40% oil by weight, often on tarmac (oil-based) roads. The real volume of oil needed to equip the world with cars is much higher than expected.
In fact, the petrol used to fuel a car is the very end of a massive industrial process that requires oil at every point. Each car requires up to the equivalent of 55 barrels of oil, and runs on tyres that are about 40% oil by weight, often on tarmac (oil-based) roads. The real volume of oil needed to equip the world with cars is much higher than expected.
"Not only is an explosion of the world car fleet a serious threat to the global environment," McKillop says, "but through its impact on oil demand, it will become a threat to international stability."
The west's road transport emissions may be growing by just 1% or 2% each year, but aviation - spurred by cheap flights and a thrusting industry backed by national governments - is expected to grow enormously in the next 20 years.
The world's aircraft have increased their greenhouse gas emissions by 50% in the past decade, and these are growing by 4% a year. The British government expects people to travel three times as much within the next 25 years.
Aircraft already contribute 3.5% of the world's greenhouse gases, but if unchecked, this will reach 5% within 25 years. Should this happen, says the EU, all the carbon savings made via the Kyoto treaty will be cancelled out. And at the moment, the aviation industry has no economic or physical limits.
This leaves the developing countries in a fix. If just 10% of the present population of China and India - about 200 million people - adopted a western lifestyle, and took the equivalent of a return flight from London to New York once a year, about 850m extra tonnes of greenhouse gases would be emitted. This is roughly what Britain emits in about five years. The effect on the climate would be immense.
But the demand for personal mobility is now so great, and the need to control emissions so urgent, that a simple, easy-to-understand technology that can get people from A to B cleanly and efficiently is desperately needed.
A case, perhaps, for the wheel coming full circle, and people taking to bicycles once again.