The term carbon footprint is how much carbon goes into the air because of something done by people or that is not done by nature. Doing something that burns fuel will make carbon dioxide gas (CO2). It is the total amount of greenhouse gases produced to directly and indirectly support human activities, usually expressed in equivalent tons of carbon dioxide. Just as walking on the sand leaves a footprint, burning fuel leaves carbon dioxide in the air, which is called a carbon footprint. Total carbon footprint/emission would include energy emissions from human activities - that is, from heat, light, power, and refrigeration and all transport related emissions from cars, freight, and distribution.