Firefox Emissions Plug-In Measures The Global Cost of Your Travel

Real Costs "is a Firefox plug-in that inserts emissions data into travel related e-commerce website. The first version adds CO2 emissions information to airfare websites such as Orbitz.com, United.com, Delta.com, etc. Following versions will work with car directions, car rental, and shipping websites. Think of it like the nutritional information labeling on the back of food... except for emissions."

Download it here. [Via]