What Are Carbon Footprints

Carbon footprint is a modern catchphrase often thrown around as a general interpretation of the social impact on global warming. Although a scientifically unified definition is still in debate, Thomas Weidmann and Jan Minx of the ISA UK Research and Consulting firm points out the commonality by which all definitions follow. They outline how the term "Carbon Footprints stands for a certain amount of gaseous emissions that are relevant to climate change and associated with human production and/or consumption activities." This is where the agreement between common definitions ends. Other important determining aspects such as proper units of measure, and how we should quantify what a carbon footprint is, is still being debated 1.

Some scientists believe that discussions of carbon footprints should only include CO2 emissions. Others believe that gases such as methane and nitrous oxide should enter the equation. Some scientists believe that indirect emissions should be included into all pertinent calculations, while other groups believe only direct emissions should be considered. The lack of a universal definition and calculation standard helps create confusion amongst the general public, which is unfamiliar with global warming rhetoric. If scientists cannot formulate comprehensive guidelines representing the human effect on our environment, it is impossible for the general public to formulate a significant movement towards social and habitual change.

Although some may disagree with recent scientific research and recommendations, environmental instability is a reality that affects all societies. Even conservative governmental organizations are beginning to recognize the present dangers of global warming, although their actions are not providing the type of rapid social change that is necessary. Some greenhouse gases occur naturally in the Earth's atmosphere. These gases include Carbon Dioxide (CO2), Methane (CH4), and Nitrous Oxide (N2O). However, recent human activities and social practices have rapidly changed atmospheric concentrations of these elements 2.

We know that gases in the earth's atmosphere can contribute to the greenhouse effect, both directly and indirectly. Direct effects occur when the gas itself absorbs radiation. Indirect radiative forcing occurs when chemical transformations of the substance produces other greenhouse gases, when a gas influences the atmospheric lifetimes of other gases, and/or when a gas affects atmospheric processes that alter the radiative balance of the earth 3.

Carbon footprint calculations are based on direct and indirect emission principles. The primary footprint is the measure of direct CO2 emissions from the burning of fossil fuels through domestic consumption and transportation. These are footprints that we have direct control over. The secondary footprint is the measure of indirect CO2 emissions from the lifecycle of products we incorporate into our daily lives, including foods, clothing, other goods, and services. By spending more on products and buying products that are produced far away, we steadily contribute more carbon emissions 4.

The most accurate carbon calculators implement consumption-based equations. This inclusion helps pinpoint the scale of the issues, and the necessary means to further reduce one's carbon footprint. According to the Berkeley Institute Of The Environment, a typical household in the United States emits about 50 tons of greenhouse gases per year. This shocking number takes into account consumption of energy, fuels, goods and services, and relevant emissions related to government and industrial activities. The global average for greenhouse gas emissions per year is only 10 tons per household 5, which means that the average U.S. household produces 400 percent more carbon emissions than the average global household.

If diligent action is not taken to curb carbon emissions and greenhouse gases produced by human activity, the average temperature of the Earth's surface could increase by 3.2 to 7.2 degrees Fahrenheit by the year 3000. Although the ultimate effects of increasing temperatures are unknown, we are already beginning to see the effects of climate change. Some of these present environmental effects include changing rainfall patterns, a drastic shift in snow and ice levels, and rising sea levels 6.


1. Wiedmann, T. and J. Minx, Ecological Economics Research Trends, (Hauppauge NY: Nova Science Publishers, 2008), 1-11, [source]

2. "Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2007," Environment Protection Agency, 15 April 2009: 25, [source]

3. "Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2007," Environment Protection Agency, 15 April 2009: 26, [source]

4. "What Is A Carbon Footprint?" Carbon Footprint Ltd, [source]

5. "Cool Climate Program Overview," The Berkeley Institute Of The Environment, January 2009. [source]

6. "Basic Information," Environmental Protection Agency, [source]