The average American releases about 50,000 pounds of carbon dioxide into the atmosphere each year.  A large portion of that comes from our homes and wasted, wasted energy.  Matter of fact, according to a recent McKinsey study, the single most cost-effective way to reduce GHG emissions is via building insulation.  Click on over to the Time Earth-Friendly Home graphic and move the lens around for other ideas to reduce GHG emissions and save some dolla, dolla bills.  Before you click over though, I will say, this is pretty basic information, but at least they provide some numbers and illustrate the impact of concerted effort. 

While you’re over there, check out this article, too:
++51 Things We Can Do to Save the Environment [Time]