From American Public Media:
The Earth coudn’t support its 6.6 billion residents if everyone lived like a typical American. Consumer consequences will tell you how many planets it would take to support your lifestyle on a planetary scale and share some ideas for making your “footprint” a little smaller.
This formula has been making the rounds of the blogosphere, news and ads. The game walks you through some lifestyle questions such as the energy usage, transportation, food and shopping, and results show how many “Earths” worth of natural resources it would take to sustain all 6.6 billion humans if we all lived just like you. In my case, we’d need 3.5 planet Earths :-(