Green Impact: 3 out of 5
What It Is:
Your carbon footprint is the amount of greenhouse gases you're responsible for releasing each year.
Why It Matters:
According to the EPA, the average household generates 20,750 pounds of carbon dioxide per year. It would take a two-acre forest roughly a year to absorb that amount.
How to Crunch (and Reduce) Yours:
The most comprehensive online calculators factor in transportation habits, home energy usage, diet, and waste production.
"I use the calculator to find where the worst problems may be," says Paul McRandle, creator of the Natural Resource Defense Council's Household Savings Calculator. That and the EPA's emissions calculator provide a yardstick.
For example, if you give up red meat, your diet's carbon weight will be less than half that of the average American.