Carbon Glossary of Terms

Carbon Glossary of Terms

Carbon Glossary of Terms


To avoid giving credits to projects that would have happened anyway, rules have been specified to ensure additionality of the project i.e. to ensure the project reduces emissions more than would have occurred in the absence of the project. A project is additional if its proponents can document that realistic alternative scenarios to the proposed project would be more economically attractive or that the project faces barriers that carbon finance helps it overcome.



Planting of new forests on lands that historically have not contained forests



The term is also synonymous with the term business-as-usual (BAU) scenario, although the term BAU has fallen out of favor because the idea of “business as usual” in century-long socio-economic projections is hard to fathom. In the context of transformation pathways, the term baseline scenarios refers to scenarios that are based on the assumption that no mitigation policies or measures will be implemented beyond those that are already in force and/or are legislated or planned to be adopted.



The unit of measurement that is used to compare the relative climate impact of the different greenhouse gases. The CO2e quantity of any greenhouse gas is the amount of carbon dioxide that would produce the equivalent global warming potential.



Carbon neutrality, or having a net zero carbon footprint, refers to achieving net zero carbon emissions by balancing a measured amount of carbon released with an equivalent amount sequestered, avoided, or offset.



One Carbon Offset represents a quantity of greenhouse gas (GHG) emissions reductions, measured in units (metric tons) of carbon dioxide equivalent (CO2e) that occur as a result of a discrete project. The emissions reductions from that project can be sold to enable the purchaser/owner to claim those GHG reductions as their own. Then these reductions can be used to reduce, or offset, any GHG emissions for which the purchaser is responsible.



A standard that helps to ensure that carbon offset projects meet certain quality requirements, such as additionality and third party verification. Several offset standards exist within the voluntary and compliance carbon markets, and each has a different set of requirements depending on its focus and scope.



The Compliance Offsets Program is an important cost-containment element within the broader Cap-and-Trade Program. The California Air Resources Board issues ARB Offset Credits to qualifying projects that reduce or sequester greenhouse gases (GHG) pursuant to six Board-approved Compliance Offset Protocols. Compliance offsets are tradable credits that represent verified GHG emissions reductions or removal enhancements from sources not subject to a compliance obligation in the Cap-and-Trade Program. In addition to their climate and other environmental benefits, offset credits provide important cost containment and compliance flexibility for covered entities.



A market-based instrument aiming at meeting a mitigation objective in an efficient way. A cap on GHG emissions is divided in tradable emission permits that are allocated by a combination of auctioning and handing out free allowances to entities within the jurisdiction of the trading scheme. Entities need to surrender emission permits equal to the amount of their emissions (e.g., metric tons of CO2). An entity may sell excess permits to entities that can avoid the same amount of emissions in a cheaper way. Trading schemes may occur at the intra-company, domestic, or international level (e.g., the flexibility mechanisms under the Kyoto Protocol and the EU-ETS) and may apply to carbon dioxide (CO2), other greenhouse gases (GHGs), or other substances.



Greenhouse gases are those gaseous constituents of the atmosphere, both natural and anthropogenic, that absorb and emit radiation at specific wavelengths within the spectrum of terrestrial radiation emitted by the Earth’s surface, the atmosphere itself, and by clouds. This property causes the greenhouse effect. Water vapour (H2O), carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4), and ozone (O3) are the primary GHGs in the Earth’s atmosphere. Moreover, there are a number of entirely human-made GHGs in the atmosphere, such as the halocarbons and other chlorine- and bromine-containing substances, dealt with under the Montreal Protocol. Beside CO2, N2O, and CH4, the Kyoto Protocol deals with the GHGs sulphur hexafluoride (SF6), hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs).



The deceptive or misleading use of advertising and marketing to overstate an organization’s environmental or sustainable practices



Activities that change forest management practices and increase carbon stock on forest lands managed for wood products, such as saw timber, pulpwood, and fuelwood



The Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC) is an international treaty adopted in December 1997 in Kyoto, Japan, at the Third Session of the Conference of the Parties (COP3) to the UNFCCC. It contains legally binding commitments, in addition to those included in the UNFCCC.



When an emission reduction from a carbon offset project in one area causes an increase in emissions somewhere outside of the project scope i.e. where conserving a forest in one region shifts logging activity to another area of forest



Removal of greenhouse gases (GHGs) from the atmosphere by deliberate human activities, i.e. in addition to the removal that would occur via natural carbon cycle processes



Achieved when anthropogenic CO2 emissions are balanced globally by anthropogenic CO2 removals over a specified period; also referred to as carbon neutrality



Achieved when anthropogenic emissions of greenhouse gases to the atmosphere are balanced by anthropogenic removals over a specified period. Where multiple greenhouse gases are involved, the quantification of net zero emissions depends on the climate metric chosen to compare emissions of different gases (such as global warming potential, global temperature change potential, and others, as well as the chosen time horizon).



An offset quality criterion that relates to the robustness and durability of the emission reduction generated by a carbon offset project



Planting of forests on lands that have previously contained forests but that have been converted to some other use



A publicly accessible database that tracks ownership of carbon offsets over their lifetime



To permanently remove carbon offsets from the market to ensure they are not re-sold. Usually offsets are retired by giving them individual serial numbers and placing them in an official registry.



A situation where the net GHG benefit, taking into account project or program emissions, removals, and leakage, in any monitoring period, is negative. The amount of a reversal is calculated as the difference between the current total-to-date net GHG benefit of the project or program, compared to the total-to-date net GHG benefit of the project or program at the previous verification event.



An independent assessment of the carbon offset project design and baseline calculations by an accredited third-party auditor that takes place before the project activity is underway



An independent assessment of quantification of actual emission reductions achieved by a carbon offset project, carried out by an accredited third-party auditor after the project is underway



A carbon credit created by a project that has been verified outside the Kyoto Protocol. One VER corresponds to one ton of CO2e emission reductions.



The segment of the carbon market for carbon offset transactions outside government-related regulatory schemes i.e. offsets purchased by organizations wishing to offset their carbon on a voluntary basis.


Information courtesy Intergovernmental Panel on Climate Change, Verra, and California Air Resources Board.