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Carbon footprint

  A carbon footprint is a "measure of the impact human activities have on the environment in terms of the amount of green house gases produced, measured in units of carbon dioxide"[1] It is meant to be useful for individuals and organizations to conceptualize their personal (or organizational) impact in contributing to global warming. A conceptual tool in response to carbon footprints are carbon offsets, or the mitigation of carbon emissions through the development of alternative projects such as solar or wind energy or reforestation. A carbon footprint can be seen as a subset of earlier uses of the concept of ecological footprints. The average UK carbon footprint is 9.4 Tonnes Per Person.


Defining a Carbon Footprint

The carbon footprint can be seen as the total amount of carbon dioxide (CO2) and other greenhouse gases emitted over the full life cycle of a product or service. Normally a carbon footprint is usually expressed as a CO2 equivalent (usually in kilogrammes or tonnes), which accounts for the same global warming effects of different greenhouse gases (UK Parliamentary Office of Science and Technology POST, 2006). Carbon footprints can be calculated using a Life Cycle Assessment (LCA) method, or can be restricted to the immediately attributable emissions from energy use of fossil fuels.

An alternative definition of carbon footprint is the total amount of carbon dioxide attributable to the actions of an individual (mainly through their energy use) over a period of one year. This definition underlies the personal carbon calculators. The term owes its origins to the idea that a footprint is what has been left behind as a result of the individual's activities. Carbon footprints can either consider only direct emissions (typically from energy used in the home and in transport, including travel by cars, aeroplanes, rail and other public transport), or can also include indirect emissions (including CO2 emissions as a result of goods and services consumed). Bottom-up calculations sum attributable CO2 emissions from individual actions; top-down calculations take total emissions from a country (or other high-level entity) and divide these emissions among the residents (or other participants in that entity).

Age-related carbon footprint

A number of studies have calculated the carbon footprint of organisations and nations. One UK (2007) study examined age-related carbon emissions based on expenditure and consumption. The study found that on average people aged 50-65 years have a higher carbon footprint compared to any other age group. Individuals aged 50-65 years old have a carbon footprint of approximately 13.5 tonnes/capita per year compared to the UK average of 12 tonnes.[2]

Carbon footprint of Christmas

An analysis of the carbon footprint of Christmas in the UK shows that consumption of items such as food, travel, lighting and gifts at Christmas produces as much as 650 kg of carbon dioxide (CO2) emissions per person - equal to 5.5% of the UK annual carbon footprint. Over Christmas, the average person could produce as much as:

26 kg of CO2 from Christmas food, 96 kg of CO2 from Christmas Car travel, 218 kg of CO2 from extravagant lighting displays, 310 kg of CO2 on Christmas Shopping.

Christmas carbon emissions could be reduced by up to 60 per cent to about 250 kg. [3]

Reducing a carbon footprint

The carbon footprint can be efficiently and effectively reduced by applying the following steps:

  • Life Cycle Assessment (LCA) to accurately determine the current carbon footprint
  • Identification of hot-spots in terms of energy consumption and associated CO2-emissions
  • Optimisation of energy efficiency and, thus, reduction of CO2-emissions and reduction of other GHG emissions contributed from production processes
  • Identification of solutions to neutralise the CO2 emissions that cannot be eliminated by energy saving measures.

The last step includes carbon offsetting; investment in projects that aim at the reducing CO2 emissions, for instance biofuels or tree planting activities.

Kyoto Protocol, carbon offsetting, and certificates

As recognised on a scientific basis, carbon dioxide emissions to air (and the emissions of other GHG's) are almost exclusively associated with the conversion of energy carriers like natural gas, crude oil, etc. The carbon content released during the energy conversion process reaches the atmosphere and is deemed to be responsible for the global warming process (i.e. climate change).

The Kyoto Protocol defines legally binding targets and timetables for cutting the greenhouse-gas emissions of industrialized countries that ratified the Kyoto Protocol. Accordingly, from an economic or market perspective, one has to distinguish between a mandatory market and a voluntary market. Typical for both markets is the trade with emission certificates:

  • Certified Emission Reduction (CER)
  • Emission Reduction Unit (ERU)
  • Verified Emission Reduction (VER).

The mandatory market

To reach the goals defined in the Kyoto Protocol with least economical costs the following flexible mechanisms were introduced for the mandatory market:

  • Emissions trading
  • Clean Development (CDM)
  • Joint Implementation (JI)

The voluntary market

In contrast to the strict rules set out for the mandatory market, the voluntary market provides companies with different options to acquire emissions reductions. A solution, comparable with those developed for the mandatory market, has been developed for the voluntary market, the Verified Emission Reductions (VER). This measure has the great advantage that the projects/activities are managed according to the quality standards set out for CDM/JI projects but the certificates provided are not registered by the governments of the host countries or the Executive Board of the UNO. As such, high quality VERs can be acquired at lower costs for the same project quality. However, at present VERs can not be used in the mandatory market.

The voluntary market in North America is divided between members of the Chicago Climate Exchange and the Over The Counter (OTC) market. The Chicago Climate Exchange is a voluntary yet legally binding cap-and-trade emission scheme whereby members commit to the capped emission reductions and must purchase allowances from other members or offset excess emissions. The OTC market does not involve a legally binding scheme and a wide array of buyers from the public and private spheres, as well as special events that want to go carbon neutral.

There are project developers, wholesalers, brokers, and retailers, as well as carbon funds, in the voluntary market. Some businesses and nonprofits in the voluntary market encompass more than just one of the activities listed above. A report by Ecosystem Marketplace shows that carbon offset prices increase as it moves along the supply chain——from project developer to retailer. [1].

While some mandatory emission reduction schemes exclude forest projects, these projects flourish in the voluntary markets. A major criticism concerns the imprecise nature of GHG sequestration quantification methodologies for forestry projects. However, others note the community co-benefits that forestry projects foster. Project types in the voluntary market range from avoided deforestation, afforestation/ reforestation, industrial gas sequestration, increased energy efficiency, fuel switching, methane capture from coal plants and livestock, and even renewable energy. Renewable Energy Certificates (RECs) sold on the voluntary market are quite controversial due to additional concerns.[2]. Industrial Gas projects receive criticism because such projects only apply to large industrial plants that already have high fixed costs. Siphoning off industrial gas for sequestration is considered picking the low hanging fruit; which is why credits generated from industrial gas projects are the cheapest in the voluntary market.

The size and activity of the voluntary carbon market is difficult to measure. The most comprehensive report on the voluntary carbon markets to date was released by Ecosystem Marketplace and New Carbon Finance in July of 2007.[3].

Criticism of the term

One criticism of the term carbon footprint is that it is politically correct.

Another is that a "conceptual method" of "personalizing" each person's contribution to global warming is at best useless, and probably harmful, if it is true that human contributions to global warming are negligible. Those arguing the latter position include the founder of the cable TV Weather Channel, John Coleman, who called "global warming" the Greatest Scam in History, and S. Fred Singer, Professor Emeritus of Environmental Sciences at the University of Virginia and founding dean of the School of Environmental and Planetary Sciences at the University of Miami, in his book Unstoppable Global Warming: Every 1,500 Years

Other activities

A carbon label, which shows the carbon footprint embodied in a product in bringing it to the shelf, was introduced in the UK in March 2007 by the Carbon Trust. Examples of products featuring their carbon footprint are Walkers Crisps, Innocent Drinks, and Boots shampoos.

The Climate Conservancy, is a U.S. non-profit founded by Stanford University scientists that is working with companies to assess the GHGs emitted across the full life cycle of consumer packaged goods. The organization plans to label products with a Climate Conscious metric based on GHG intensity (CO2e per $) in order to provide a meaningful standard for comparing different products.

CarbonCounted, which launched in early 2007, is a Canadian not-for-profit based GHG carbon label system that allows companies to link with and leverage their supply chain. The CarbonCounted footprint can be displayed on a product or service. CarbonCounted is a "live" carbon dioxide emission footprint with the entire supply chain continually participating as opposed to a static calculation.

Carbon Reduction Institute, NoCO2 & LowCO certification labels were launched in Australia to allow consumers to determine the reductions of GHG emissions that companies have made. The Carbon Reduction Institute uses a combination of direct life cycle studies and life cycle analysis based on a financial control rational to determine the carbon footprint of companies.

Hot Women Campaign[4] is an international campaign by the Global Warming Alliance aimed at getting women to voluntarily reduce their carbon footprint by 5%.

See also

  • Life cycle assessment
  • List of countries by carbon dioxide emissions per capita
  • List of countries by greenhouse gas emissions per capita
  • Global warming
  • Ecological footprint
  • Ecosharing
  • Energy policy
  • Telecommuting
  • Green conventions, meetings & events
  • 2000 Watt society


  1. ^ Carbon Footprint LTD accessed Nov 10, 7:39am CST
  2. ^
  3. ^


  • Parliamentary Office of Science and Technology POST (2006). Carbon footprint of electricity generation. October 2006, Number 268
  • World Energy Council Report (2004). Comparison of energy systems using life cycle assessment.
  • Energetics (2007). The reality of carbon neutrality.
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Carbon_footprint". A list of authors is available in Wikipedia.
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