Carbon Management Glossary


The process of an independent third party checking the methodology, data and calculation processes to ensure that they are robust.

Carbon neutral

Commonly accepted terminology for something having net zero emissions (for example, an organisation or product). As the organisation or product will typically  have caused some greenhouse gas emissions, it is usually necessary to use carbon offsets to achieve neutrality.  Carbon offsets are emissions reductions that have been made elsewhere and which are then sold to the entity that seeks to reduce its impact. In order to become carbon neutral it is important to have a very accurate calculation of the amount of emissions which need to be offset - requiring calculation of a carbon footprint.

Carbon dioxide CO2

The most important greenhouse gas. CO2 emissions result from the combustion of fuel, from land use changes and from some industrial processes.  CO2 emissions are limited by the Kyoto protocol.

Carbon dioxide equivalent CO2(e)

There are six main greenhouse gas emissions which cause climate change and are limited by the Kyoto protocol. Each gas has a different global warming potential. For simplicity of reporting, the mass of each gas emitted is commonly translated into a carbon dioxide equivalent CO2(e) amount so that the total impact from all sources can be summed to one figure.

Carbon footprint

The total set of greenhouse gas emissions caused by an individual or organisation, event or product. It should be expressed in carbon dioxide equivalent CO2(e).

 Emissions Conversion Factor

When calculating emissions from energy use it is common to know what quantity of energy was used, either in kWh or by volume or mass of input material. Emissions factors enable a conversion to be made from the input measure of energy to the amount of carbon dioxide emissions that will result. UK conversion factors for energy to CO2 are published by DEFRA.

Greenhouse gases

Greenhouse gases are those which contribute to the greenhouse effect when present in the atmosphere. Six greenhouse gases are regulated by the Kyoto Protocol, as they are emitted in significant quantities by human activities and contribute to climate change.  The six regulated gases are Carbon dioxide CO2, Methane CH4, Nitrous oxide N2O, Hydrofluorocarbons HFCs, Perfluorocarbons PFCs and Sulphur hexafluoride SF6. Emissions of greenhouse gases are commonly converted into carbon dioxide equivalent CO2(e)  based on their 100 year global warming potential. This allows a single figure for the total impact of all emissions sources to be produced in one standard unit. Conversion factors of greenhouse gas to CO2(e) are calculated by the IPCC and DEFRA publish guidance on which set of conversion factors to use.

The Greenhouse Gas GHG Protocol

A widely used standard for emissions reporting. The protocol covers project emissions reporting and corporate emissions reporting. The corporate emissions reporting standard provides a methodology for calculation of a carbon footprint. The protocol was developed by the World Resources Institute and the World Business Council for Sustainable Development.

ISO 14064

ISO 14064 is an international standard for corporate emissions reporting. It builds on the approach outlined in the Greenhouse Gas Protocol.


An emissions reduction, commonly resulting from a project undertaken in the developing world, which has been sold to compensate for emissions elsewhere. Offsets are commonly used to net off corporate emissions so that an organisation can claim to be carbon neutral.