Here’s an interesting exercise to measure your ecological footprint. I did a similar but more professional quiz for my class on Environment Assessment last fall.
The world has only 4.5 biologically productive acres/person. This particular quiz reports my footprint to be 18 acres/person, mainly because I reported the average distance I drive every week to be 100-200 miles (I drive up to my fiance’s place on alternate weekends). The average footprint for the US is 24 acres/person. The quiz tells me that if everyone in the world lived like me, we’d need 4 planets. A sobering thought indeed.
You can learn more about ways to reduce your footprint at the Redefining Progress site.