For almost as long as I can remember, the experts have been saying that the US, with 5% of the world's population, consumes a third or more of the Earth's resources. That is no longer true.

China has now overtaken America as the world's leading resource consumer. Among the basic commodities - grain and meat in the food sector, oil and coal in the energy sector, and steel in the industrial sector - China now consumes more of each of these than the US except for oil. It consumes nearly twice as much meat - 67m tonnes compared with 39m tonnes in the US; and more than twice as much steel - 258m tonnes to 104m.

The important questions now are: what if China's consumption per person of these resources reaches the current US level, and how long will it take for China's income per person to reach the US level?

If China's economy expands at 8% a year in the decades ahead, its income per person will reach the current US level in 2031. If at that point China's resource consumption per person were the same as that in the US today, its 1.45 billion people would consume the equivalent of two-thirds of the current world grain harvest. China's paper consumption would be double the world's current production. Say goodbye to the world's forests.

If China were to have three cars for every four people - as in the US - it would have 1.1bn cars. Worldwide today there are 800m cars. To provide the roads and parking spaces to accommodate such a vast fleet, China would have to pave an area comparable to the land it now plants in rice - 29m hectares (72m acres). It would use 99m barrels of oil a day; the world currently produces only 84m barrels daily, and may never produce much more.

The western economic model - the fossil fuel-based, car-centred, throwaway economy - is not going to work for China. If it does not work for China, it will not work for India, which by 2031 is projected to have a population even larger than China's. Nor will it work for the 3 billion other people in developing countries who are also dreaming the "American dream".

In an increasingly integrated global economy, where all countries are competing for the same oil, grain and iron ore, the existing economic model will no longer work for industrial countries either.

Time for Plan B

Sustaining our early 21st-century global civilisation now depends on shifting to a renewable energy powered, re-use/recycle economy with a diversified transport system. Business as usual - Plan A - cannot take us where we want to go. It is time for Plan B, time to build a new economy.

Glimpses of the new economy can already be seen in the wind farms of western Europe, the solar rooftops of Japan, the fast-growing hybrid car fleet of the US, the reforested mountains of South Korea, and the bicycle-friendly streets of Amsterdam. Virtually everything we need to do to build an economy that will sustain economic progress is already being done in one or more countries.

In this economic restructuring, the biggest challenges will come in the energy economy as the world strives simultaneously to reduce carbon emissions and dependence on oil. Over the past five years, production of energy from oil and coal expanded by 2% and 3% a year, respectively, while wind and solar energy grew by some 30% a year. The transition from fossil fuels to renewable energy sources is under way, but, unfortunately, it is not moving nearly fast enough to stabilise the climate or slow the depletion of oil reserves.

Among the new sources of energy - wind, solar cells, solar thermal, geothermal, small-scale hydro and biomass - wind is developing fastest, hinting at what the new energy economy will look like. In Europe, which is leading the world into the wind era, wind-electric generation is sufficient to meet the residential needs of some 40 million people. The European Wind Energy Association has projected that by 2020 some 195 million Europeans - half of the region's population - could get their residential electricity from wind.

Wind energy is growing fast for the following reasons: it is abundant, cheap, inexhaustible, widely distributed, clean and climate benign. No other energy source has this combination of attributes.

The US has enough harnessable wind energy to satisfy national electricity needs several times over. Wind electric generation in America, which expanded by 35% last year, is on the verge of exploding as rising natural gas prices spur investment in this cheaper source of electricity. China could easily double its current electricity generation from wind alone.

For the US vehicle fuel sector, which is widely seen as one of the most challenging segments of the world energy economy to restructure, the key to quickly reducing oil use and carbon emissions is petrol-electric hybrid cars. Fuel efficiency ratings from the US Environmental Protection Agency show that the average new car sold in the US last year travelled 22 miles to the gallon, compared with 55 miles a gallon for the Toyota Prius, a mid-sized petrol-electric hybrid.

If, for oil security and climate stabilisation reasons, America over the next 10 years replaced its entire fleet of passenger vehicles with super-efficient petrol-electric hybrids, petrol use could easily be cut in half. A change in the number of cars or miles driven would not be necessary.

Beyond this, a petrol-electric hybrid with an additional storage battery and a plug-in capacity would allow motorists to use electricity exclusively for short-distance driving, such as the daily commute and grocery shopping. This could cut US petrol use by an additional 20%, for a total reduction of 70%. Investment in thousands of wind farms across the US to feed cheap electricity into the grid would mean Americans could do most short-distance driving with wind energy, dramatically reducing carbon emissions and the pressure on world oil supplies.

Using timers to recharge batteries during the low-demand hours late at night, with electricity coming from wind farms, costs the equivalent of, or less than, 60 cents a gallon of petrol. The US has not only an inexhaustible alternative to oil but also an incredibly cheap one.

Taxing negative activities

The key to restructuring the global economy is restructuring national tax systems. In effect, lowering taxes on income and increasing those on environmentally destructive activities. This has progressed fastest in Europe, where countries are taxing negative activities, such as carbon emissions, the generation of rubbish (landfill taxes), and cars driven in cities.

A four-year plan adopted in Germany in 1999 systematically shifted taxes from labour to energy. By 2001, this plan had lowered fuel use by 5%. It had also accelerated growth in the renewable energy sector, creating some 45,400 jobs by 2003 in the wind industry alone - a number that is projected to rise to 103,000 by 2010.

In 2001, Sweden launched a bold new 10-year environmental tax shift designed to convert 30bn kroner (£2.2bn) of income taxes to taxes on environmentally destructive activities. Much of this shift - £624 per household - is levied on road transport, including substantial hikes in vehicle and fuel taxes.

Cities that are being suffocated by cars are using stiff entrance taxes to reduce congestion. The revenue from London's congestion charge for cars entering the inner city is being invested in improving the bus network, which carries 2 million passengers daily. The goal is a restructuring of the London transport system to reduce congestion, air pollution and carbon emissions, and to increase mobility.

Ecologists have long been convinced of the need to restructure the global economy in order to protect natural support systems and to stabilise the climate. China's growth is also convincing economists of the need for restructuring.

Our civilisation is not the first to move onto an environmentally unsustainable economic path. Some earlier civilisations in a similar situation were able to make the required adjustments in the time available. Others were not. We study the archaeological sites of the latter.

Of all the resources needed to build an economy that will sustain economic progress, none is more scarce than time. With climate change, we may be approaching the point of no return. The temptation is to reset the clock. But we cannot. Nature is the timekeeper.

· Lester R Brown is president of the Earth Policy Institute and author of Plan B 2.0: Rescuing a Planet Under Stress and a Civilisation in Trouble, published by WW Norton & Co, RRP £10.99. To order a copy for £9.99, with free UK p&p, go to Guardian.co.uk/bookshop or call 0870 836 0875.