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Vol. 16 No. 4 - November 2010

Carbon footprints for climate change mitigation

 By: Divya Pandey and Madhoolika Agrawal*

Global warming is real and human beings are expected to get burns sooner or later if significant actions are not taken to control the rising temperatures immediately. The increase in temperatures is due to the enhanced greenhouse effect due to anthropogenic release of greenhouse gases (GHGs) into the atmosphere. Of these, the Kyoto gases i.e. carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulphur hexafluoride (SF6) are the biggest contributors. For this reason, relevant steps have been taken at local to national levels worldwide in the forms of carbon and energy taxes; adoption of alternative energy sources including wind, hydro, geothermal and nuclear energy; promotion of terrestrial, oceanic and geologic carbon sequestration; and generating funds for GHG mitigation projects through carbon market. It has become one of the most popular topics in the public domain. Contributions to the public concern towards the issue came from famous books like “The End of Nature (Bill McKibben, Random House, 1989)”, The Two-Mile Time Machine (Richard Alley, Princeton University Press, 2000), “The Revenge of Gaia (James Lovelock, Allen Lane, 2006)”, “Six Degrees (Lynas, Fourth Estate, 2007)” and movies like “An Inconvenient Truth”; activities of non government organizations and media covering political negotiations regarding the issue. Besides these, a renowned term which has played an important role in proliferating awareness regarding the individual responsibilities to limit GHGs and hence global warming, particularly in developed world is “carbon footprint” (CF). Originally as a part of “ecological footprint”, CF was an estimate of biologically productive land and sea area required to absorb as much carbon dioxide as was generated during the lifetime of an individual, or an activity. In lieu its importance in greenhouse gas accounting and representations, CF became independent and increasingly popular although its native form entirely got modified. The definition of carbon footprint is still not uniform among the studies, however there is an apparent nexus that it refers to the amount of GHGs emitted into or removed from the atmosphere in terms of carbon dioxide equivalents, over a specified time period from a well defined set of activities for which the entity is responsible. For this relatively new concept, calculation methodologies are still evolving but it has proven assistive in taking mensuration of greenhouse gas emissions to households in an easily conceivable manner. Its use therefore has increased among the businesses besides encouraging personal carbon calculating facilities commercially. This article presents a brief introduction of carbon footprint, its calculation and significance. An attempt has been made to analyze how commercial businesses have responded to this technique of emission quantification and representation.

Carbon footprint calculations

In order to estimate the net contribution of any activity to global warming, all the relevant GHG emissions or removals, whether direct or indirect have to be identified and accounted. In other words, it involves the complete life cycle assessment of the product or activity with respect to GHGs. To address complexities in such analyses, guidelines have been formulated. Important resources are GHG protocol of World Resource Institute and World business council for sustainable Development, Guidelines to National GHG inventories 1996 and 2006 of IPCC and ISO 14064 (part 1 and 2). Besides these, methods have been developed by government and non government organizations, as well as by those involved in carbon footprinting business. UK DEFRA, USEPA, The Climate Registry, and Carbon Trust are few to name. There are three basic steps in CF calculation:

  1. Identification of all relevant phases through which the product, event or activity has passed and with which GHG emissions are associated.

  2. Estimation of GHGs emitted at each identified phase.

  3. Calculation of net GHGs released or removed, in terms of CO2-e (usually at 100 year time horizon).

Life cycle analyses helps identifying the relevant stages of the product, while emissions and removals are calculated through direct measurements or utilizing emission factors and models. Practically, only direct emissions (technically called Tier I) such as in transportation and fossil fuel burning in boilers, and emissions embodied in energy (Tier II) are included in CF calculations. For realistic estimates however, tier III i.e. emissions associated with use and disposal of a product should also be considered. Due to complexity and because neither these emissions are considered in carbon markets nor are mandatory under GHG accounting guidelines, this phase is left out in most of the studies. But as more and more carbon footprinting studies will calculate end use emissions, sector specific emission factors can be developed to cover broader boundaries with reduced chances of error.

Popularity of carbon footprint

There exists a long list of activities for which CF have been calculated. Be it an individual, our daily activities, consumer products, big events, organizations, cities and countries, utilities or natural systems; CF is widely employed as a quantitative indicator of climate friendliness.

Hundreds of individual and household carbon calculators have surged the internet, which yield CFs within minutes based on few inputs. Scientific comparisons indicate that these calculators yield variable results and hence it becomes difficult to select the appropriate one. Similarly, online calculators can yield CF of food and travelling, particularly the air travels. The business of carbon offsetting i.e. supporting GHG emission reduction or sequestration facilities financially has given a boost to such calculators. These calculators compel their customer to offset footprints. However, few of them are verified to make sure that emission reduction could not have occurred if not supported financially through offset sale. Offsets are usually generated through afforestation programs in the third world countries and supporting renewable energy options. Big events like conferences and sports events too get their CF calculated and take necessary actions to manage their CF. An example to quote is the forthcoming London Olympics 2012, for which CF calculations are going on. The estimated CF will be reduced as much as possible. FIFA world Cup 2006 was declared as carbon neutral through purchasing offsets for its CF of 1.0 x 105 t CO2-e.

While the World Bank, UNO and UNESCO declared that they will calculate and reduce their CFs, educational institutions are not lagging behind. Carbon footprints of University of British Colombia and University of Pennsylvania have been estimated to be 8.2750 x 104 and 3.0 x 105 t CO2-e respectively. These were calculated using the emission factors derived from respective resources, and it was found that for such institutions, emissions embodied in purchased electricity contribute the largest to CF. A scoping study has already been conducted to carry out carbon footprinting of schools in UK. For cities, states and countries, CF is being utilized to guide the areas of emission reductions. City of Seattle (7.013 x 106 t CO2-e in 2000), The City of Vancouver, Canada (4.1983 X 107 t CO2-e 2006), Hawaii (2.154 X 107 t CO2-e in 2005) are few examples. UNDP estimated world’s per capita carbon footprint to be 4.5 t CO2-e in 2004. It included only CO2 emissions in CF calculation for nations and found United Arab Emirates leaving the biggest footprint with 34.1 tonCO2 and smallest by India (1.2 t CO2). The results were found inconsistent with another study carried out by Edgar and Peters (2009), who made use of a database “Global Trade Analysis Project” and considered other GHGs also. Highest CF and hence lowest carbon consciousness was reported for Luxembourg (33.8 t CO2-e). Over consumptive behaviour of developed countries yields higher CF whereas developing countries are unable to afford emission control measures and cleaner techniques and substitutes. Even then, their CF has been found to be the lowest. Carbon footprint for Bangladesh, Mozambique and Uganda is estimates as 1.1t CO2-e.

On the entire arena of getting prepared for fighting global warming, commercial businesses hold a unique position as the target points of the laws and governments when it comes to emission reductions and environmental protection, but are also equally prone to every change in society and public behavior. At the same time, they have to reap economic benefits from all the expected or induced changes. They have sensed that the future will definitely be carbon and energy constrained and therefore have started conforming accordingly. In Carbon Disclosure Project 2009, 475 corporate over the world participated to get their footprints calculated with 83 % revealing their emissions upto tier II only. However, total tier 3 emissions of 5.8 x 109 t CO2-e outweighed the combined emissions of tier I and II (0.6 and 3.6 x 109 t CO2-e, respectively).  It indicates that emissions beyond tier II have the biggest share in CF except for few biggest known emitters including thermal power plants and cement manufacturing industries.

Consumer preferences have shifted towards the products with low carbon content. LEK consulting (2007) carried out a survey which showed that 44% of the consumers preferred to buy products providing information about its CF and 43% preferred to the product with low CF immaterial of its higher price. Therefore, corporates are in a race to count and cut their CF. News Corporation and internet service provider Google announced to go carbon neutral whereas others including General Motors, Oil giant British Petroleum and Virgin Group, declared to invest in technologies that help reducing their GHG emissions. Regardless of the fact that natural processes contributing to GHG emissions are beyond our control, CF of devastation caused by hurricane Katrina on US coast and wildfires have also been estimated.

Importance of carbon footprints

The word ‘CF’ itself gives an indication that it shows something about the quantity of carbon or related species. Its obvious cognition makes it popular among the public as an indicator of one’s contribution towards global warming. An aware citizen of the world therefore appreciates all possible measures that tend to reduce CF of humankind. This has resulted in fundamental changes in governance, people behaviour and businesses. It is clearly visible in the form of carbon taxes and tariffs, numerous researches going on to evaluate carbon sequestration options and rapidly growing carbon market. An important and substantial contribution of CF is that it has compelled businesses to look towards cutting their GHG emissions, whether or not heavy taxes are imposed by the government. It is due to the business motivation rather than environmental consciousness that is generated as more and more consumers tend to shift towards conservative lifestyle and buy more environment friendly goods and services. When an organization reveals and takes actions to limit CF, its image is improved besides adding to its adaptation to expected stricter emission norms and getting benefits in form of incentives for limiting emissions.

Individual carbon footprinting facilities have generated huge money through sale of carbon offsets resulting in rise of carbon offsetting business that imparts a sense of carbon neutrality among its buyers. For this reason, voluntary carbon market has grown dramatically since 1989.

Ambiguities to be addressed

A vital point is that, CF has become immensely popular business tool and CO2-e is now being looked as a commodity, although neither there is a standard method to verify and compare the CF calculations, nor is to determine the efficacy of carbon offsets. Variations in sources, rates and periods of emissions/sequestration amongst different processes and products or events make comparisons more problematic. There is a need of strict vigilance over the carbon markets and assets exchanged there. Similarly coherence in CF calculations is indispensible when it is related to money transactions. Standard guidelines make tier III optional, which is the known biggest contributor to total GHGs emitted. Methodologies to include these emissions are thus essential.  CF of consumer products as well as in other carbon calculating facilities must clearly indicate the extent of emissions covered to avoid misleading interpretations. An initiative has been taken in the form of carbon labeling in some countries, but unless it too provides details of the life cycle stages covered in an understandable manner, its motive will be astray.


Contribution of CF for making GHG accounting illustrious at large scale is appreciable. It has compelled businesses to cut down their emissions even if not required so legally through raised public awareness towards eco friendly products. This reflects its strength if employed in a well regulated way. Although general public tends to calculate and reduce its CF for aroused sense of environmental consciousness, there is no control over carbon calculating and offset sale facilities. The business of carbon offsets is growing uncontested. This must be checked so as to generate money for actual reductions. As CF is still evolving, more studies are required in order to account for emissions and removals beyond tiers I and II for more representative estimates that will guide in better GHG management and control measures. In addition to these, there is an urgent need to disseminate information about how to interpret CF, among general public, so that merely what is shown to them doesn’t misled them.

*Laboratory of Air Pollution and Global Climate Change, Department of Botany, Banaras Hindu University, Varanasi-221005, India.

This article has been reproduced from the archives of EnviroNews - Newsletter of ISEB India.

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