A carbon footprint converts the total emissions impact of an activity or organisation into the equivalent amount of carbon dioxide (CO2), measured by weight.
Further Information
Carbon Footprint Definition
“A Carbon Footprint is the sum of all greenhouse gas emissions for an individual, business/organisation, or community.”
Carbon Trust
Carbon Dioxide Equivalency
For the purposes of clarity, rather than report on all harmful greenhouse gases individually, the standard is to convert each of the harmful gas emissions into the “equivalent amount of carbon dioxide” (Eurostat, 2023) based on its global warming potential over a 100-year period.
As the base of this standard, carbon dioxide, has a global warming potential of one.
The final sum of all contributing emissions/ processes is then expressed in terms of carbon dioxide (CO2) equivalence (abbreviated to CO2e) by weight in metric measurements. For example, 25kgCO2e. This is a carbon footprint.
Carbon Accounting
The Greenhouse Gas Protocol is the equivalent of an accounting standard but for greenhouse gases.
The legal need to calculate and report on a carbon footprint is dependent upon the size and location of an entity.
Under EU law, large companies and publicly listed small-to-medium enterprises are required to report on social and environmental risks. (European Commission, 2023) Greenhouse gas emissions fall within these disclosure requirements. (EU, 2023)
At present, the are no requirements for smaller businesses or individuals to estimate their carbon footprints but many choose to do so for ethical, competitiveness or supply-chain reasons.
Scope of Measurement
The scope of what is measured is important. Best practice considers both direct and indirect sources. The GHG protocol splits these into three scopes:
- Scope 1 is Direct. That is, any emissions that come from owned or controlled sources.
- Scopes 2 and 3 are Indirect.
- Scope 2 relates to purchased electricity consumed by an entity.
- Scope 3: captures upstream activities of purchased materials and services and downstream activities such as waste disposal, product use and outsourced activities.
This figure below shows the potential scopes for a business.
The current protocol explicitly factors in business travel and employee commuting, but as Cloud Carbon Footprint (2024) confirms:
“There are currently no guidelines for reporting Scope 3 emissions as part of the Greenhouse Gas (GHG) Protocol, which cloud provider usage would fall under. However, we hope more and more organizations report on both location-based and market-based emissions from cloud usage.”
In the case of those working from home, emissions may be further under-reported if Scope 1 activities for heating such as burning fossil fuels are not reported. Likewise, for Scope 2 use of electricity to power devices.
There is also a potential further carbon cost if employees use their own internet service providers, computing equipment, and smartphones, although this is more pertinent at an individual level.
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Learn more about the genesis of global reporting standards and how businesses use them.
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