For Carol Kelly, biking to and from work is a no-brainer: She doesn't have to deal with the notorious Seattle traffic, she can exercise without visiting the dreary gym and she saves money on gas. And, of course, she acknowledges that her swap of a tailpipe for pedals contributes -- at least in a small way -- to tackling climate change. "I don't necessarily connect it to climate, but it's a bonus," said Kelly, 47, a fine arts professor at Seattle University, as she waited on her bike at a stop sign Friday evening in the Green Lake neighborhood of Seattle.