The "game" starts off with this explanation:
The Earth couldn'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 provide some ideas for making your 'footprint' a little smaller.
If you play, you go along and tell the system how much energy you use and your avatar's village gets cleaner or dirtier based on your choices. At the end, a chart shows where you're green and where you're not. I understand why APM uses a lot of the variables (do you walk or drive, where does your food come from, etc.), but I do not understand why it matters whether my flights are in business, economy, or first class. Wait, I guess if everyone wanted the space required by first class seating, there would have to be more planes in the air.
I went through the process, and discovered that my personal energy use would require 2.8 Earths, which is way more than I assumed. I rarely drive, eat some organic/local food and make sure the lights are out when no one is in the room. You know, the normal stuff. Looks like it's not enough. If you think knowing your personal Earths requirement sounds like a good idea, why not share your result with us in the comments.