A carbon footprint is a measure of the amount of carbon dioxide (CO2) released through the burning of fossil fuels.
Carbon dioxide is composed of one atom of carbon and two atoms of oxygen.
Fossil fuels are defined as hydrocarbons, predominantly coal, natural gas or fuel oil, formed from the remains of decayed plants and animals. A small portion of hydrocarbon-based fuels are biofuels derived from atmospheric carbon dioxide and because of that, they do not increase the amount of carbon dioxide in the atmosphere.
The loose definition of fossil fuels also includes the hydrocarbons containing natural resources not derived from plant of animal sources. These are called mineral fuels.
The burning of fossil fuels is the largest source of emissions of carbon dioxide.
The importance of the carbon footprint is how carbon dioxide contributes to the greenhouse effect.
When the sun warms the Earth the energy (heat) is released back into space. To make sure that the Earth remains warm, the atmosphere creates a "blanket" made up greenhouse gases which helps trap the heat that has warmed the Earth from escaping. This is known as the greenhouse effect. A precise amount of greenhouse gases (or GHG) are required for this to work efficiently: too little GHG and the Earth becomes too cold, too many GHG and the Earth becomes too warm.
The major greenhouse gases are water vapour, methane, nitrous oxide, ozone and carbon dioxide.
Certain human activities increase the levels of these naturally occurring gases and contribute to the increase in the greenhouse effect.
Of the amount of human responsible GHG, carbon dioxide from the burning of fossil fuels accounts for approximately 60%. The remaining 40% comes from methane, nitrous oxide and other gases (which come from industrial activity).
Over the last two centuries, the use of fossils fuels and the amount used has increased dramatically, thus increasing the greenhouse efffect by about 40% since 1750. CO2 concentrations have been monitored continuously since 1958. One specific increase has been the demand for petrol which is derived from oil.
Since the Industrial Revolution, the amount of CO2 in the atmosphere has risen by about 30%. This amount is predicted to double in the next 100 years. The temperatures on Earth are set to rise by 2 and 4 degrees Celsius over the next century. By comparison, since the beginning of civilisation temperatures have varied by less than 1 degree.
The effects of this increase in temperature to our planet will be dramatic, causing severe climate change, affecting both humans, flora and fauna.
We need to increase our use of renewable energy to reduce the CO2 emissions and thus reduce our carbon footprint.