# What is a Carbon Footprint?

*Published:* 2007-05-10
*Author:* Bill Chameides

You hear a lot of talk these days about "carbon footprints". But what is a carbon footprint, anyway?

Carbon dioxide (CO2), while not the only greenhouse gas, is the [most abundant](https://blogs.edf.org/climate411/2007/04/26/slicing-the-greenhouse-gas-pie-what-gases/). CO2 is emitted into the atmosphere when we burn fossil fuels, and most of the energy in this country comes from burning fossil fuels. Thus, anything that requires energy to manufacture, transport, or operate causes the emission of CO2 (see my previous post, [The Carbon Footprint of… Everything](https://blogs.edf.org/climate411/2007/03/20/eco-labeling/)).

A "carbon footprint" is the amount of CO2 released by an activity or entity. So what’s your carbon footprint?

It’s difficult to make an exact calculation because the carbon footprint of so many things is unknown – for example, the amount of CO2 emitted in the manufacturing of your shoes. But the basics are known, and can give a very good picture of how your choices contribute to global warming. The kind of home you live in, how much you drive, and how often you fly can account for half a person’s carbon footprint.

You can [calculate your carbon footprint](http://www.fightglobalwarming.com/carboncalculator.cfm) for these three main elements on our Web site. You enter basic information about your lifestyle, and we take it from there. After the calculation, the site describes how you can minimize or offset your emissions – smart heating and cooling, smart use of appliances, smart driving, switching to compact fluorescent light bulbs, and selecting offsets.

Here are some statistics to think about:

- The average American car emits seven tons of CO2 per year.
- The average American person emits 20 tons of CO2 per year.
- The United States emits 7 billion tons of CO2 per year.
- The world emits 30 billion tons of CO2 per year.

If you’re confused by the notion that gases like CO2 have weight, check out my earlier post [Picturing a Ton of CO2](https://blogs.edf.org/climate411/2007/02/20/picturing-a-ton-of-co2/).