When you fly, there's not much you can do about the jet's emissions. However TerraPass has come up with a clever way to offset this and other ways you increase your carbon footprint.

They call it carbon balancing. When you purchase a TerraPass, the they dollars you pay are used to fund renewable energy projects (wind energy, biomass, industrial efficiency). "Every TerraPass member has taken a simple positive step to fight global warming. Every TerraPass purchase is a vote for innovation, efficiency, and clean energy. Together, we have eliminated over 79 million pounds of carbon dioxide emissions." The latest from TerraPass is a partnership with Expedia, which is offering TerraPass to every U.S. traveler who books a flight through their site.

TerraPass does other stuff, too. You can get a free TerraPass in exchange for your old cellphones or PDAs, drivers can use TerraPass to offset their emissions, as can business owners. The TerraPass site has calculators that help you determine the kind of TerraPass you need to balance your emissions. If I pay the $49.95 it would take to balance my car's annual emissions, I would get a member kit with a decals and a bumpersticker to show that I'm balanced, if not exactly clean.