TRAVEL, UNFORTUNATELY, ISN’T VERY GOOD for the environment. Most modes of travel require some level of carbon emissions, and this contributes to man-made climate change. But some modes of travel are cleaner than others: the Union of Concerned Scientists did a study on what the cleanest modes of travel are, and broke it down into a handy chart.

It’s simple to read: it breaks the emissions down based on the distance traveled and the number of people traveling with you (on the grounds that, if you have four people in a car, you are splitting emissions four ways, as opposed to making the same trip with a single person in the car). One of the most interesting findings is that there’s a noticeable difference between emissions for passengers in coach seats and passengers in first class seats. This is because first class seats take up about twice as much space as coach seats, meaning they account for about twice as much emissions.

Next time you’re planning your trip, pull up this handy guide to decide how you’re going to travel. And if you want to read more about the research and the methodology, visit the UCS’s report here.