Here is a great video by WWF (not to be confused with the WWE). The WWF created the ad as a part of its campaign to promote cycling for the environment.
I try not to harp too much about the environmental benefits of bike riding because, for most Midwestern Americans there are other reasons to ride that are more compelling: convenience and health, to name just two. But you really can't ignore the environmental benefits from cycling, and cycling should be part of the larger conversation on how to survive in a world with finite resources.
Obviously, more bikes on the road mean fewer cars, which, in turn, reduces greenhouse gas emissions and other pollutants that contribute to global warming and air pollution. Bike paths also leave a smaller footprint, so exchanging paths for road building reduces the amount of greenspace that is paved over with concrete. Increased greenspace has aesthetic benefits and directly changes current weather patterns, since massive amount of concrete heats up the air (creating heat islands).
But the environmental benefits from bicycles are not limited to reduced air pollution and emissions. Bicycling reduces noise pollution and light pollution. It also contributes to a sense of community because bicyclists must interact with their broader environment--and the people in it. They are not closed off, shut away in a car, windows rolled up, music blasting. They can't as readily be jerks to others. There is no (or at least less) anonymity.
Bicyclists also tend to be happier. They have reduced levels of cortisol (stress hormone) and increased levels of endorphins rolling around in their bodies from the exercise. They have been breathing fresh air and listening to the birds. They can think clearly from seeing trees and green space.
Just imagine this world: people who are no longer depressed or suffering the ennui and exasperation that comes from everyday life, happily riding their bikes around cities with plenty of green space (trees, parks), interacting, talking, laughing with one another. The levels of ambient noise is greatly reduced, and, as a consequence, levels of stress. Doesn't this sound like a pleasant place to live?
I'm not stuck in la-la land here. These places do exist. They exist in the Netherlands, in Denmark, in Sweden and many other places. These are cities and countries where the people and their governments believe that it's important for people to exercise, to get fresh air, to enjoy reduced noise, light, and concrete pollution. It's important for people to interact with and trust their neighbors. And, yes, while all of this riding does help the "environment," it also helps all of us in countless other ways.
I applaud the WWF for promoting cycling for the benefit of the environment. I hope that we continue the conversation, including in our concept of "environment" everything around us.