Came across this very cool looking new tool, defintely one worth using if you live in North America, and hopefully it should soon work for European airlines - Real Costs
By using this plug in when on major airline and e-commerce travel sites, you get to see the carbon emissions of the travel you are buying and can compare across different modes of transport such as plane, train and car. To me this is key, individual action is not so much about any particular single pledge you may make. Rather the pledge is just a means to a state of mind whereby you are more conscious of the impact of all our decisions and consumer choices and purchases, where the carbon impact has a higher share of mind. Real costs is a very useful tool to help consumers get to that mindset.