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A carbon footprint is "the total set of greenhouse gases (GHG) emissions caused by an organization, event or product" [1]. For simplicity of reporting, it is often expressed in terms of the amount of carbon dioxide, or its equivalent of other GHGs, emitted.

The concept name of the carbon footprint originates from ecological footprint discussion.[2] The carbon footprint is a subset of the ecological footprint and of the more comprehensive Life Cycle Assessment (LCA).

An individual, nation, or organization's carbon footprint can be measured by undertaking a GHG emissions assessment. Once the size of a carbon footprint is known, a strategy can be devised to reduce it, e.g. by technological developments, better process and product management, changed Green Public or Private Procurement (GPP), Carbon capture, consumption strategies, and others.

The mitigation of carbon footprints through the development of alternative projects, such as solar or wind energy or reforestation, represents one way of reducing a carbon footprint and is often known as Carbon offsetting.


By area


Of products

Several organizations have calculated carbon footprints of products;[3] The US Environmental Protection Agency has addressed paper, plastic (mainly candy wrappers), glass, cans, computers, carpet and tires. Australia has addressed lumber and other building materials. Academics in Australia, Korea and the US have addressed paved roads. Companies, nonprofits and academics have addressed manufacture and operation of cars, buses, trains, airplanes, ships and pipelines. The US Postal Service has addressed mailing letters and packages. Carnegie Mellon University has estimated the CO2 footprints of 46 large sectors of the economy in each of eight countries. Carnegie Mellon, Sweden and the Carbon Trust have addressed foods at home and in restaurants.

The Carbon Trust has worked with UK manufacturers on foods, shirts and detergents, introducing a CO2 label in March 2007. The label is intended to comply with a new British public available specification (i.e. not a standard), PAS2050,[4] and is being actively piloted by The Carbon Trust and various industrial partners.[5]

Of electricity

The following table compares, from peer-reviewed studies of full life cycle emissions and from various other studies, the carbon footprint of various forms of energy generation: Nuclear, Hydro, Coal, Gas, Solar Cell, Peat and Wind generation technology.

The Vattenfall study found renewable and nuclear generation responsible for far less CO2 than fossil fuel generation.
Emission factors of common fuels
Energy Intensity
Coal &0000000000000092.510000B:91.50–91.72
Oil &0000000000000073.00000073[8] &0000000000000003.4000003.40 &0000000000000893.000000893[7]
Natural gas &0000000000000068.300000cc:68.20
&0000000000000003.0000003~ &0000000000000040.000000TL0–1[7]
Nuclear power
Hydroelectricity &-1000000000000000.0460000.046[6] &0000000000000015.00000015[6]
Conc. Solar Pwr &0000000000000040.00000040±15#
Photovoltaics &0000000000000000.3300000.33[6] &0000000000000106.000000106[6]
Wind power &-1000000000000000.0660000.066[6] &0000000000000021.00000021[6]

Note: 3.6 MJ = megajoule(s) == 1 kW·h = kilowatt-hour(s), thus 1 g/MJ = 3.6 g/kW·h.
Legend: B = Black coal (supercritical)–(new subcritical), Br = Brown coal (new subcritical), cc = combined cycle, oc = open cycle, TL = low-temperature/closed-circuit (geothermal doublet), TH = high-temperature/open-circuit, WL = Light Water Reactors, WH = Heavy Water Reactors, #Educated estimate.

These studies thus concluded that hydroelectric, wind, and nuclear power always produced the least CO2 per kilowatt-hour of any other electricity sources. These figures do not allow for emissions due to accidents or terrorism. Lastly some relatively new green renewable electricity generation methods, wind power for example, emit no carbon during operation, but do leave a minor footprint during construction phase using the cradle-to-grave approach of the complete production life cycle.

Of Heat and various combined heat and power schemes, heat pumps etc

The previous table gives the carbon footprint per kilowatt-hour of electricity generated, which is about half the world's man-made CO2 output. The CO2 footprint for heat is equally significant and research shows that using waste heat from power generation in combined heat and power district heating, chp/dh has the lowest carbon footprint.[9] much lower than micro-power or heat pumps.

Kyoto Protocol, carbon offsetting, and certificates

Carbon dioxide emissions into the atmosphere, and the emissions of other GHGs, are often associated with the burning of fossil fuels, like natural gas, crude oil and coal.

The Kyoto Protocol defines legally binding targets and timetables for cutting the GHG 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:

Mandatory market mechanisms

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

The CDM and JI mechanisms requirements for projects which create a supply of emission reduction instruments, while Emissions Trading allows those instruments to be sold on international markets.

- Projects which are compliant with the requirements of the CDM mechanism generate Certified Emissions Reductions (CERs).
- Projects which are compliant with the requirements of the JI mechanism generate Emissions Reduction Units (ERUs).

The CERs and ERUs can then be sold through Emissions Trading. The demand for the CERs and ERUs being traded is driven by:

- Shortfalls in national emission reduction obligations under the Kyoto Protocol.
- Shortfalls amongst entities obligated under local emissions reduction schemes.

Nations which have failed to deliver their Kyoto emissions reductions obligations can enter Emissions Trading to purchase CERS and ERUs to cover their treaty shortfalls. Nations and groups of nations can also create local emission reduction schemes which place mandatory carbon dioxide emission targets on entities within their national boundaries. If the rules of a scheme allow, the obligated entities may be able to cover all or some of any reduction shortfalls by purchasing CERs and ERUs through Emissions Trading. While local emissions reduction schemes have no status under the Kyoto Protocol itself, they play a prominent role in creating the demand for CERs and ERUs, stimulating Emissions Trading and setting a market price for emissions.

A well-known mandatory local emissions trading scheme is the EU Emission Trading Scheme (EU ETS).

Voluntary market mechanisms

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.[10]

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 additionality concerns.[11] 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 2007.[10]

ÆON of Japan is firstly approved by Japanese authority to indicate carbon footprint on three private brand goods in October 2009.

See also


  1. ^ "What is a carbon footprint?". UK Carbon Trust. Retrieved 2009-07-24. 
  2. ^
  3. ^ "CO2 Released when Making & Using Products". Retrieved 27 October 2009. 
  4. ^
  5. ^
  6. ^ a b c d e f g h i j k l m n o p q r Prof. Bilek, Marcela; Dr. Hardy, Clarence, Dr. Lenzen, Manfred & Dr. Dey, Christopher (2008). "Life-cycle energy balance and greenhouse gas emissions of nuclear energy: A review" (PDF). SLS - USyd - USyd-ISA - pubs - pandora-archive Energy Conversion & Management 49 (8): 2178–2199. Retrieved 2009-11-04. 
  7. ^ a b c d e Fridleifsson,, Ingvar B.; Bertani, Ruggero; Huenges, Ernst; Lund, John W.; Ragnarsson, Arni; Rybach, Ladislaus (2008-02-11). O. Hohmeyer and T. Trittin. ed (pdf). The possible role and contribution of geothermal energy to the mitigation of climate change. Luebeck, Germany. pp. 59–80. Retrieved 2009-04-06. 
  8. ^ a b Dowlatabadi, H (9 November 2007), "Strategic GHG reduction through the use of ground source heat pump technology", Environmental Research Letters (UK: IOP Publishing) 2: 044001 8pp, doi:10.1088/1748-9326/2/4/044001, ISSN 1748-9326,, retrieved 2009-03-22 
  9. ^
  10. ^ a b
  11. ^


External links

Simple English

The carbon footprint is how much carbon emissions are left on the Earth by human activity.


The use of carbon based resources is usually applied to the pollution caused by using fossil fuels. Burning fossil fuel (oil, gas, coal) to release energy produces carbon emissions. This also results in the greenhouse effect. A carbon footprint is the total greenhouse gas emissions directly caused by individual, organisation, event or product.

The Media

It has become an expression often used by media to do with sustainability. Single people and businesses are often asked to consider the amount of carbon their particular use of resources is producing and how this affects the environmental concern and the likely link to global warming. This is often applied to travel and in particular oil use in air transport and automotive transport.


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