Check out how Saul Griffith visualizes climate change at WattzOn. He breaks everything down into the same units of energy (Watts) and compares it that way. In many ways, a more accessible to track a carbon footprint -- and you can track your own energy, too.
I learned about Saul and WattzOn recently at an AIGA webcast of the AIGA San Francisco conference CompostModern. But I think this talk is very similar.
