1. Whenever possible, take the bus.
Unfortunately for us, travel is an activity that puts a lot of carbon in the atmosphere. This isn’t to say we should never travel, just that we should be thoughtful about the way in which we travel. The most carbon efficient way to travel (aside from walking or biking) is by bus. The least efficient option is to fly first class. The Union of Concerned Scientists made up this handy little chart to help you figure out the best way for you to travel in any given situation.