I work remotely whenever possible. I got rid of my car some time ago. Locally, I go pretty much everywhere by public transport. For domestic travelling I try to use high-speed trains instead of going by plane (also because it's much less of a hassle with today's airport security theatre).

Though concern about climate change was a factor, I'd be lying if I said that that was the main motivation for making these decisions personally. The main reason for me is simplicity (owning a vehicle means one more thing to take care of) and making better use of my time (by being able to work on the train for example).