There are a lot of reasons I ride my bicycle, mostly having to do with how much fun it is. From an environmental perspective, I ride primarily to avoid consuming fossil fuels. We're rapidly approaching a time when the "easy to find" oil will plateau, and we will be forced to develop other sources of hydrocarbons to continue to feed our addiction. I want no part of it.
The Alberta oil sands are the poster child for alternative hydrocarbon sources. The damage being inflicted on the Earth is visible from space. Thanks, but no thanks. I'll ride my bicycle.