As a bicycle rider, I laughed out loud at the ridiculous remarks Rep. Ed Orcutt, R-Kalama, made about bicyclists adding to climate change. It hard to conceive that even he believes what he said. (He has since apologized for his comment).
However, in the very outside chance that heavy breathing does contribute to global warming, I guess it would be appropriate to add an additional tax to a whole list of items, not just bicycles, starting with running shoes, birth control pills and condoms.
On the other hand, I strongly suspect that the hot air that spews forth from the mouths of politicians contributes more to global warming than anything we bicyclists do.