The "ecological footprint" measures the real price of consumption

If every human being consumed as much as the Americans do, one Earth would not be enough. It would take over five to support such a world. By Chinese standards, though, one would be enough.

The calculation is based on the "ecological footprint," a measurement used in a report recently presented by the London-based New Economics Foundation (NEF). The size of the ecological footprint is determined by the planet's surface area needed to provide food, energy and consumer goods for one human being. At present, an equal division of productive land among the world's population would equal 1.8 hectares per person. The average American citizen exploits 9.4 hectares; the Chinese need only 1.6 per capita.

As the NEF's report noted, the numbers for China are also influenced by the carbon emissions of the industries that Western countries had moved to China in the 1990s. These countries now import the products they used to make themselves. The effect is called "carbon laundering."

At the rate of French or British consumption, 3.1 planets would be needed; the number for Germany is 2.5 and for Japan 2.4. The world's average is 1.3.

These numbers will certainly have an impact on the negotiations over a successor to the Kyoto Protocol on curbing climate change, which expires in 2012.