Carbon offsetting is a concept that is increasing in popularity both for businesses and individuals as consciousness grows around energy consumption and its effects on the environment.  To put it simply, it's kind of like an environmental swap meet – if you take something, put an equal something back to keep the balance even.  For example, investing in renewable energy sources can "even out" the energy and emissions required for air travel. The catch is that is has to be an investment in an offset that didn't already exist before your contribution (no piggybacking on the good work of others). 

There are many companies easily found through a web search that can help you find ways to reduce your own carbon footprint on the world.  See what you can find that fits for you.