When you walk across a floor with wet feet, you can see a line of ‘feet’ behind you. Those are your footprints. In the same way, people leave behind a carbon footprint that shows how much carbon dioxide they make in their lives. If you travel by car and buy lots of new things, you have a bigger carbon footprint. If you walk and buy second – hand things, you have a smaller carbon footprint. These are some of the things that make a carbon footprint smaller or bigger.