Carbon footprint
"A carbon footprint is a way of expressing the amount of CO2 emitted as a result of a person's day-to-day life. For a business, it is the CO2 emitted as a result of its operations. Carbon footprints are usually expressed in tonnes of carbon dioxide emitted per year. They are calculated from information such as travel, burning of fossil fuels (eg: to heat buildings) and use of non-renewable electricity.

Carbon dioxide is a so called greenhouse gas causing global warming . Other greenhouse gases which might be emitted as a result of your activities are e.g. methane and ozone. These greenhouse gases are normally also taken into account for the carbon footprint. They are converted into the amount of CO2 that would cause the same effects on global warming (this is called equivalent CO2 amount).

Source: www.timeforchange.org

Climatologists (sccientists who study climate) have analyzed the global warming that has occurred since the late 1800's. A majority of climatologists have concluded that human activities are responsible for most of the warming. Human activities contribute to global warming by enhancing Earth's natural greenhouse effect. The greenhouse effect warms Earth's surface through a complex process involving sunlight, gases, and particles in the atmosphere. Gases that trap heat in the atmosphere are known as greenhouse gases.

Source: www.nasa.gov

Data From: World Resource Insitute/www.timeforchange.org