What is a carbon footprint and what is its relevance to climate change and global warming?

If the whole world is slogging it out to reduce carbon emissions, it will be nice to have a metric by which such emissions can be measured, wouldn’t it?

Enter Carbon Footprint.

A carbon footprint is a measure of amount of greenhouse gases produced directly and indirectly by human activities, usually expressed in equivalent tons or Kg of carbon dioxide (CO2).

In other words: When you drive a car, the engine burns fuel which emits a certain amount of CO2, depending on its fuel consumption and the driving distance. When you heat your house with oil, gas or coal too, you generate CO2. Even if you heat your house with electricity, the generation of the electrical power most likely would have emitted a certain amount of CO2. When you buy food and goods, the production of such food and goods also emit CO2.

Each of these activities thus leaves a carbon footprint.

To provide some benchmarks for CO2 footprint:

• The average U.S. household carbon footprint is about 50 tons CO2e per year.
• While driving, for each (US) gallon of gasoline fuel consumed, 8.7 kg carbon dioxide (CO2) is emitted.
• A typical coal based power plant emits about 0.9-1 Kg of CO2 for every kWh (unit) of power generated.

As you can guess, the carbon footprint is a powerful tool to understand the impact of personal behaviour on global warming. Most people are surprised when they realize the amount of CO2 their activities create! If you personally wish to contribute towards global warming reduction, calculation and constant monitoring of your personal carbon footprint is a good starting point as it makes you REALIZE that you too are a contributor to global warming.

Calculating an activity’s true carbon footprint is not easy however. Take for instance, the making of a plastic toy: Its production includes not only the direct emissions resulting from the manufacturing process and the transportation of the toy to the shop; it also includes a whole host of indirect emissions, such as those caused by the extraction and processing of the oil used to make the plastic in the first place.  The traditional way of estimating a carbon footprint – so-called ‘lifecycle assessment’ – involves adding up as many of the emissions pathways as feasible.

While some challenges still remain on how the complete carbon footprint can be calculated for any activity, it is still useful to have an approximate estimate – because, what we cannot measure, we cannot control.