I started cycling citing mostly financial and fitness reasons, but climate was always there buzzing in the background. As time went on, I learned about Peak Oil and the implications of AGW, the 6th mass extinction, and the debt bubble. All of it cemented my resolve to avoid motor transport wherever practically possible, for the sake of my daughter and grand children. Most do not look that far into the future when making the choice about motor based transport (of all kinds). Even buses and trains are unsustainable, despite their recent green-washing. As other's have pointed out, cycling itself isn't environmentally friendly as the green-washers might have you believe. They are for the most part a product of the industrial economy, which is itself quite destructive. The manufacturing processes are damaging. However, they are the lesser of many evils. Cycling is only marginally worse than walking in man made boots. Only walking bare footed is really environmentally neutral, assuming your food source (energy) is also sustainable.
I figure citing 'personal competitive advantage' and 'making a living' in the job marketplace as an excuse to drive around hither and thither will not be a well received once the next generation hold their equivalence of the Nuremberg trials. In any case, combustion engines will be the privilege of the elite on the other side of this decade if things carry on the way there are, why not get used to getting about only by muscle power now?
I'd prefer to be part of the solution and not the problem. Not to say I am an angel, I'm still working on it


. I don't blame people for their choice to drive either. It's the system. It forced me down that same path for a time, but I took the blue pill and can't look back.
In the mean time, I have also reduced my consumption of meat, don't buy things new unless I really have to, mostly do without where I can, and stopped flying. In the near future, I plan to drop to 3-4 days a week at work so I have more time to grow my own food in anticipation of the collapse of the market economy. Yes. Seriously. It's coming.