What is a carbon footprint?

http://www.treehugger.com/files/2008/02/carbon-footprint-green-basics.php

Dunn, Collin. Green Basics: Carbon Footprint. (c) 2008.

Here's a summary of Collin Dunn's excellent explanation of a carbon footprint.

What is a carbon footprint? It’s away to understand global warming. It measures the amount of greenhouse gases like CO₂ that come from the things we use.

There are different formulas to calculate carbon footprints, for individual people or products or for entire countries. Carbon dioxide is the most common greenhouse gas, but there are others. Personal carbon footprints are calculated by the energy we use for our homes, transport, and things we consume.

We need to know the size of our carbon footprints, so that we can reduce them. Three ways to reduce carbon footprints are using energy more efficiently, reducing our consumption of energy, and using carbon offsets. There are several web sites to use to calculate your carbon footprint.