Most tools that allow you to calculate your impact on the environment soon ask for non-specific pledges, contact information, and money to offset your impacts on the environment. Well, Bello Mundo (sustravel.co.uk) has created an airline travel carbon calculator that, instead of giving you abstract numbers and asking for monetary offsets, tells you exactly how to change your lifestyle to offset your plane flight.

For example, my recent honeymoon to Italy could easily be offset by BIKING (instead of driving) FOR 16,000 MILES!  OK, maybe that's not a good example.  How about using a CFL for 12,000 hours...that's easy. That's just two bulbs in my house for one year! 

The Bello Mundo calculator actually helps a guy understand what 10,000 kg of carbon dioxide means, and how airline travel relates to car travel and household power use. It makes things seem less abstract making it, in my opinion, a noble and useful tool.