Glossaries

Climate Change Glossary

Simplified Terminology for the Forest Products Industry

Climate Change is defined by the United Nations Framework Convention on Climate Change (UNFCCC) as “A change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods.”

This page lists nearly 100 terms that appear frequently in news and journal articles on the topic of climate change. The definitions provided are simple and straightforward, and, where possible, highlight a term’s specific relevance to the forest products industry. While these definitions have been simplified, NCASI staff are able to provide more detailed explanation upon request. For some terms, the definition is followed by a reference link to specific organizational, technical, and/or published definitions.

Throughout the glossary, the term “greenhouse gas” is abbreviated as GHG. The plural form, GHGs, refers to more than one type of greenhouse gas.

This page will be updated periodically with new terms, improved explanations, and updated definition references.

For more information, contact Adam Costanza.

A

Adaptive Capacity

Adaptive capacity is the ability of a system to adjust to the effects of climate change in ways that moderate potential damages, to take advantage of opportunities, or to cope with the consequences. A system with a high adaptive capacity (e.g., coastal saltwater marsh) could better handle the consequences of climate-induced sea level rise than a system with low adaptive capacity (e.g., a beach-side golf course).
Reference: Fifth U.S. National Climate Assessment
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Additionality

The greenhouse gas (GHG) emission reductions or removals from the mitigation activity shall be additional, i.e., they would not have occurred in the absence of the incentive created by carbon credit revenues.
Reference: The Integrity Council for the Voluntary Carbon Market

Agriculture, Forestry and Other Land Use (AFOLU)

In the context of national greenhouse gas (GHG) inventories under the United Nations Framework Convention on Climate Change (UNFCCC), AFOLU is the sum of the GHG inventory sectors Agriculture and Land Use, Land-Use Change and Forestry (LULUCF).
Reference: IPCC Expert Meeting on Reconciling Anthropogenic Land Use Emissions (2024)

Annex I Countries/Parties

Annex I Parties include the industrialized countries that were members of the OECD (Organization for Economic Co-operation and Development) in 1992, plus countries with economies in transition. Annex I countries commit themselves to returning individually or jointly to their 1990 levels of greenhouse gas emissions. Annex I parties committed to GHG emission reductions under the Kyoto Protocol.
References: Annex 1 Parties | Kyoto Protocol

Anthropogenic

Anthropogenic means “made by people” or “resulting from human activities.” Anthropogenic emissions are those produced from human activities, such as a factory or vehicle, as opposed to natural emissions sourced from decaying organic matter or volcanos, for example.
Reference: U.S. EPA

Anthropogenic Emissions and Removals

Anthropogenic emissions and removals means that GHG emissions and removals included in national inventories are a result of human activities. In the Agriculture, Forestry and Other Land Use (AFOLU) sector, all emissions and removals on managed land are taken as a proxy for anthropogenic emissions and removals.
Reference: IPCC Expert Meeting on Reconciling Anthropogenic Land Use Emissions (2024)

Avoided Emissions

The impact, measured in tons of carbon dioxide equivalent (tCO₂e), of specific mitigation actions or projects to avoid GHG emissions to the atmosphere calculated against a reference baseline.
Reference: The Carbon Neutral Protocol

B

Baseline Scenario

A baseline scenario is a hypothetical reference case of conditions that would most likely occur in the absence of climate change mitigation. Baseline scenarios can also be referred to as “business as usual” scenarios. For example, if a mill had a coal boiler in good working order that was generating process steam, and the company decided to convert it to a natural gas boiler to reduce GHG emissions, the baseline scenario would be the emissions of the coal boiler.
Reference: The Greenhouse Gas Protocol

Biogenic Carbon

The carbon embodied in or derived from biomass is biogenic carbon.
Reference: NCASI Technical Bulletin 1015

Biogenic CO₂

Biogenic carbon dioxide (CO₂) emissions are defined as CO₂ emissions related to the natural carbon cycle, as well as those resulting from the combustion, harvest, combustion, digestion, fermentation, decomposition, or processing of biologically based materials.
Reference: U.S. EPA

Business as Usual

See Baseline Scenario.

C

Cap and Trade

Cap and trade is a policy tool for controlling large amounts of emissions from a group of sources. A cap and trade program first sets a cap, or maximum limit, on emissions. Sources covered by the program then receive authorizations to emit in the form of emissions allowances, with the total amount of allowances limited by the cap. Each source can design its own compliance strategy to meet the overall reduction requirement, including the sale or purchase of allowances which can constitute a trade, installation of pollution controls, and implementation of efficiency measures, among other options dictated by the program.
Reference: U.S. EPA

Carbon

Carbon is a chemical element. In the context of climate change and GHG emissions, “carbon” should not be used interchangeably with carbon dioxide (CO₂). While carbon may be used as a shorthand for carbon dioxide, this is not correct. A ton of carbon is not a ton of CO₂. The atomic weight of carbon is 12 atomic mass units, while the weight of carbon dioxide is 44, because it includes two oxygen atoms, each with an atomic mass of 16. Thus, one ton of combusted carbon is equivalent to 44/12 = 11/3 = 3.67 tons of CO₂, and 11 tons of CO₂is equivalent to 3 tons of carbon. Likewise, a hypothetical price of $30 per ton of CO₂equals a price of $110 per ton of carbon.

Carbon Capture and Storage (CCS)

The process of capturing carbon dioxide and injecting it into geological formations underground or in the deep ocean for long-term storage.
Reference: Fifth U.S. National Climate Assessment
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Carbon Credit

Generally, a carbon credit allows the holder to emit an amount of or carbon dioxide equivalent (CO₂e) (typically one ton). The credit may be a permit or a tradeable certificate. Operationally, a carbon credit is a tradeable, intangible instrument that is issued by a carbon-crediting program, representing a GHG emission reduction to, or removal from, the atmosphere equivalent to one metric ton of carbon dioxide equivalent. This is calculated as the difference in GHG emissions or removals from a baseline scenario to the emissions or removals occurring under the mitigation activity, and any adjustments for leakage. The carbon credit is uniquely serialized, issued, tracked and retired or administratively cancelled by means of an electronic registry operated by a third party administrative body, such as a carbon-crediting program.
Reference: ISO 14068 | The Integrity Council for the Voluntary Carbon Market

Carbon Cycle

The series of processes by which carbon compounds flow among reservoirs in the environment, such as the incorporation of carbon dioxide into living tissue by photosynthesis and its return to the atmosphere through respiration, the decay of dead organisms, and the burning of fossil fuels. In the carbon cycle, carbon flow or output from one reservoir transfers carbon to other reservoir(s).
Reference: Fifth U.S. National Climate Assessment
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Carbon Dioxide (CO₂)

Carbon dioxide (CO₂) is the standard greenhouse gas (GHG) due to its …prevalence? association with anthropogenic impacts?. All other GHG’s are compared to CO₂and normalized against it to develop ”Global Warming Potentials” and carbon dioxide equivalent (CO₂e).
Reference: U.S. EPA

Carbon Dioxide Equivalent (CO₂e)

Carbon dioxide equivalent (CO₂e) is a measure used to compare the emissions from various greenhouse gases based on their global warming potential (GWP). For example, as per the Intergovernmental Panel on Climate Change (IPCC) 6^th Assessment Report, the global warming potential for methane from fossil fuels over 100 years is 29.8. This means that emissions of one million metric tons of methane has the equivalent radiative forcing effect in the atmosphere to emissions of 29.8 million metric tons of carbon dioxide. Units for carbon dioxide equivalents can be expressed as “million metric tons of carbon dioxide equivalent (MMTCO₂Eq),” or other abbreviated expressions denoting mass and CO₂e. The carbon dioxide equivalent for a gas is derived by multiplying the tons of the gas by the associated GWP: MMTCO₂Eq = (million metric tons of a gas) * (GWP of the gas).
References: IPCC 6^th Assessment | U.S. EPA

Carbon Dioxide Fertilization

The enhancement of plant photosynthesis and growth as a result of increased atmospheric carbon dioxide (CO₂) concentration.
Reference: UN Food and Agriculture Organization (FAO)

Carbon Footprint

The net total amount of GHG emissions and removals into the atmosphere over a set period of time by a person, family, building, organization, company, product, or activity. A carbon footprint is the result of a calculation that sums GHG emissions and removals. The footprint calculation can be for as long as a lifetime (in the case of a product) or as short as minutes (in the case of a car ride). The boundaries of a particular carbon footprint can vary in time and scope. When boundary conditions are not explicitly detailed, product carbon footprints typically cover the lifetime of the product and are inclusive of upstream and downstream activities associated with the product’s manufacture and end of life. It is common for the carbon footprint of a forest product to include:

Biomass carbon removal and storage in forests
Biomass carbon in paper and board products
Greenhouse gas emissions from paper and board product manufacturing facilities
Greenhouse gas emissions associated with producing wood fiber
Greenhouse gas emissions associated with producing other raw materials/fuels
Greenhouse gas emissions associated with purchased electricity, steam, heat, and hot and cold water
Greenhouse gas emissions associated with transportation
Greenhouse gas emissions associated with product use
Greenhouse gas emissions associated with product end of life

A tenth category, avoided greenhouse gas emissions, may also be included in some carbon footprint boundaries.
Reference: The European association representing the paper industry (Cepi)

Carbon Negative

An activity or operation is considered to be carbon negative if the net sum of carbon emissions and carbon removals associated with it is less than zero. If something is carbon negative, whether it is a product or a process, the atmosphere contains less greenhouse gases because of it, meaning that without that product or process, there would be more GHGs in the atmosphere. Carbon negative is often synonymous with “GHG Negative” or “Climate Negative.”
Reference: International Energy Agency

Carbon Neutral

“Carbon neutrality,” or “net zero,” carbon dioxide (CO₂) emissions are achieved when anthropogenic CO₂ emissions are balanced globally by anthropogenic CO₂ removals over a specified period. Net zero CO₂ emissions are also referred to as carbon neutrality.
Reference: IPCC AR6

Carbon Neutrality

The state of being carbon neutral.

Carbon Offsets

Third-party verified avoided GHG emissions, GHG emission reductions, or GHG removals that are made available to another organization in the form of a carbon credit to balance (as in reduce) GHG emissions. Some offsets are calculated relative to a baseline scenario that represents a hypothetical scenario for what GHG emissions (or removals) would have been in the absence of the mitigation project that generates the offsets.
Reference: ISO 14068

Carbon Removals

Anthropogenic activities removing carbon dioxide (CO₂) from the atmosphere and durably storing it in geological, terrestrial, or oceanic reservoirs, or in manufactured products. It includes existing and potential anthropogenic enhancement of biological or geochemical CO₂ sinks and direct air carbon dioxide capture and storage, but excludes natural CO₂ uptake not directly caused by human activities.
Reference: IPCC AR6

Carbon Sequestration

The process of storing carbon in a carbon pool. For example, trees and plants absorb carbon dioxide (CO₂), release the oxygen (O₂), and store the carbon (C) in their tissues.
Reference: IPCC AR6

Carbon Sink

Any process, activity, or mechanism that removes carbon from the atmosphere. A carbon sink may also refer to a physical location, defined area, or geological or biological element of Earth’s system (e.g., the ocean, a country, biomass) that stores carbon from the atmosphere for a specified period of time.
Reference: Fifth U.S. National Climate Assessment
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Climate Change

Climate change refers to a change in the state of the climate that can be identified (e.g., by using statistical tests) by changes in the mean and/or the variability of its properties and that persists for an extended period, typically decades or longer. Climate change may be due to natural internal processes or external forcings such as modulations of the solar cycles, volcanic eruptions and persistent anthropogenic changes in the composition of the atmosphere or in land use. Note that the Framework Convention on Climate Change (UNFCCC), in its Article 1, defines climate change as: ‘a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods.’ The UNFCCC thus makes a distinction between climate change attributable to human activities altering the atmospheric composition and climate variability attributable to natural causes. See also Climate
Reference: UNFCCC

Climate Change Mitigation

Active human intervention to reduce GHG emissions or increase GHG removals.
Reference: ISO 14068

Climate Feedback Loop

A cyclical environmental process that acts to amplify or reduce direct climate warming or cooling effects. An example of climate feedback would be warmer winter temperatures that allow permafrost to melt, which releases methane previously trapped by permafrost. Methane in turn is a powerful GHG that contributes to warming temperatures, thereby causing more permafrost to melt.
Reference: Fifth U.S. National Climate Assessment
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Climate Forcing

A process that alters the energy balance of the climate system is a forcing mechanism. Climate forcing usually refers to changes in the relative balance between incoming solar radiation and outgoing infrared radiation from Earth. Such mechanisms include changes in solar irradiance, volcanic eruptions, and enhancement of the natural greenhouse effect by emissions of GHGs.
Reference: Fifth U.S. National Climate Assessment
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Climate Justice

A conceptual term that climate change disproportionately affects those nations and communities where the average income is much lower than in industrial nations and communities and would have a much greater impact on populations in countries in Africa and Asia as well as lower income neighborhoods in industrial nations.
Reference: United Nations Environment Programme

Climate Mitigation

See Climate Change Mitigation

Climate Model

Climate models are used to simulate the effects of GHG emissions on Earth’s climate over time. Also known as general circulation models or GCMs, climate models use mathematical equations to characterize how energy and matter interact in different parts of the ocean, atmosphere, and land. Climate models can be discussed in terms of a Global Climate Model (also referred to as a General Circulation Model, both abbreviated as GCM).
Reference: U.S. National Oceanic and Atmospheric Administration

Climate Neutral

Synonymous with Carbon Neutral.

Climate System

The climate system is a dynamic system consisting of five major components: the atmosphere, the hydrosphere, the cryosphere (systems dominated by freezing conditions), the land surface, and the biosphere. These components are influenced by various external “forcing” mechanisms, the most important being the sun. Anthropogenic activities having effects on the climate system are also considered a forcing mechanism.
Reference: The Intergovernmental Panel on Climate Change (IPCC)

Climate Variability

Natural changes in climate that fall within the observed range of extremes for a particular region, as measured by temperature, precipitation, and frequency of events, driven by historical data . Drivers of climate variability include the El Niño Southern Oscillation and other natural phenomena.
Reference: Fifth U.S. National Climate Assessment
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Climate Velocity

Climate velocity is a metric that quantifies the distance and direction an organism must move over a specified time to keep pace with climate change. Climate velocity is measured by comparing current climate to future climate projections. Climate velocity helps guide conservation efforts by showing which specific areas may see the most rapid pace of climate change, and thus where species will need to move long distances over time to maintain a constant climate. For example, where climate velocity is high, trees will need to shift their ranges over long distances relatively quickly to track suitable climates.
Reference: Fifth U.S. National Climate Assessment
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Cradle-to-gate

An assessment that includes part of the product’s life cycle, including material acquisition through the production of the studied product and excluding the use or end-of-life stages.

Cradle-to-grave

A cradle-to-grave assessment considers impacts at each stage of a product’s life cycle, from the time natural resources are extracted from the ground and processed through each subsequent stage of manufacturing, transportation, product use, recycling, and end-of-life.

D

Direct Emissions

Emissions from sources owned or controlled by the entity.
Reference: The Greenhouse Gas Protocol

Displacement Factor

See Substitution Factor.

E

Emissions

The release of climate-altering gases and aerosols into the atmosphere from human and natural sources. in the context of climate change, typically a GHG.
Reference: Fifth U.S. National Climate Assessment
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Emission Factors

Emission factors are values for scaling emissions to activity data in terms of a standard rate of emissions per unit of activity. For example, kilograms of carbon dioxide (CO₂) emitted per barrel of fossil fuel consumed, or kilograms of carbon dioxide emitted per ton of product produced.
Reference: XBRL Units Registry

Emissions Scenarios

Quantitative illustrations of how the release of different amounts of GHGs into the atmosphere from human and natural sources will produce different future climate conditions. Scenarios are developed using a wide range of assumptions about population growth, economic and technological development, climate policies, and other factors.
Reference: Fifth U.S. National Climate Assessment
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Emissions Trading

A pollution reduction approach that enables industrial emitters to purchase reductions made by other entities and use those reductions as part of meeting their emissions compliance. Emissions trading programs have two key components: a limit (or cap) on pollution, and tradable allowances equal to the limit that authorize allowance holders to emit a specific quantity (e.g., one ton) of the pollutant. This limit ensures that the environmental goal is met and the tradable allowances provide flexibility for individual emissions sources to set their own compliance path. Because allowances can be bought and sold in an allowance market, these programs are often referred to as “market-based.” Existing emissions trading markets in the United States include carbon dioxide (CO₂) and sulfur dioxide (SO₂).
Reference: U.S. EPA

End-of-Life

The final disposition of a product. For GHG emission purposes, the end of a product’s life has the potential to generate GHG emissions. For example, forest products disposed of in uncapped landfills can emit carbon dioxide (CO₂) or methane over time as they decay. End-of-life GHG emissions are included in cradle-to-grave analyses but are not included in cradle-to-gate analyses.
Reference: GHG Protocol Category 12: End-of-life treatment of Sold Products

F

Fossil Fuel

Carbon-based fuels from fossil hydrocarbon deposits, including coal, oil and natural gas.
Source: IPCC AR6

G

General Circulation (or Climate) Model (GCM)

A global climate model (GCM) is a complex mathematical representation of the major climate system components (atmosphere, land surface, ocean, and sea ice), and their interactions. Earth’s energy balance between the four components is the key to long-term climate prediction. Models investigate the degree to which observed climate changes may be due to natural variability, human activity, or a combination of both. The main climate system components treated in a climate model are: atmosphere, land, ocean, and sea ice.
Reference: U.S. National Oceanic and Atmospheric Administration

Geo-engineering

Also referred to as climate engineering, geo-engineering is the deliberate and large-scale intervention in the Earth’s climate system with the goal of limiting climate change impacts.
Reference: University of Oxford

Global Change

Large-scale changes in the environment that may alter the Earth’s capacity to sustain life and human endeavor.
Reference: USGS Climate and Land Use Change Science Strategy

Global Warming

Global warming refers to the increase in global surface temperature relative to a reference period, averaging over a period sufficient to remove interannual variations (e.g., 20 or 30 years). A scientific-consensus choice for the baseline is 1850–1900 (the earliest period of reliable observations with sufficient geographic coverage), with more modern baselines used depending upon the application.

Reference: IPCC 2021 Annex VII Glossary

Global Warming Potential (GWP)

An index measuring the following an emission of a unit mass of a given substance, accumulated over a chosen time horizon, relative to that of the reference substance, carbon dioxide (CO₂). The GWP thus represents the combined effect of the differing times these substances remain in the atmosphere and their effectiveness in causing radiative forcing.
Reference: IPCC 2021 Annex VII Glossary

Greenhouse Effect

Greenhouse gases absorb thermal infrared radiation emitted by the Earth’s surface, by the atmosphere itself due to the same gases, and by clouds. Atmospheric radiation is emitted in all directions, including downward to the Earth’s surface. This results in GHGs trapping heat within the surface-troposphere system, called the greenhouse effect. An increase in the concentration of greenhouse gases leads to an increased infrared opacity of the atmosphere and a temperature increase of the surface-troposphere system. This radiative forcing leads to an enhancement of the effectiveness of the greenhouse effect and is called the enhanced greenhouse effect.
Reference: Fifth U.S. National Climate Assessment
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Greenhouse Gases (GHGs)

Greenhouse gases are those gaseous constituents of the atmosphere, both naturally and anthropogenically, 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 vapor (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 non-natural 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). See also Carbon dioxide (CO₂), Methane (CH₄), Nitrous oxide (N₂O) and Ozone (O₃).
Source: IPCC

Greenhouse Gas Capture

The process of collecting GHGs from a source of emissions before they enter the atmosphere. By itself, GHG capture does not necessarily include GHG storage.

Greenhouse Gas Emission Reduction

A decrease in GHG emissions from one point in time to another as the result of an activity.

Greenhouse Gas Negative

Greenhouse gas negative is synonymous with ”carbon negative” and is an activity or operation is GHG negative if it removes or sequesters more GHGs than are emitted, such that over a specified period of time there is a net decrease in GHG emissions when all aspects of the activity are summed, which can include carbon offsets. An example in the forest products industry is a bioenergy process with carbon capture and storage (CCS).
References: International Energy Agency | Fifth U.S. National Climate Assessment
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Greenhouse Gas Neutral

Synonymous with Carbon Neutral and includes all GHGs in the concept of neutrality.

Greenhouse Gas Positive

An activity or operation that emits more GHGs than it sequesters.

GHG Protocol

The Greenhouse Gas Protocol (GHG Protocol) was developed through a partnership between the World Resources Institute (WRI) and the World Business Council for Sustainable Development (WBCSD). The GHG Protocol provides accounting and reporting standards, sector guidance, calculation tools, and training for businesses and government. It establishes a comprehensive, global, standardized framework for measuring and managing emissions from private and public sector operations, value chains, products, cities, and policies. The GHG Protocol divides emissions into three Scopes:

Scope 1 – Direct GHG emissions
Scope 2 – Indirect emissions from the generation of purchased electricity and steam
Scope 3 – Other indirect GHG emissions not covered by Scope 1 and Scope 2
Reference: The Greenhouse Gas Protocol

Greenhouse Gas Removal

The process of withdrawing GHGs from the atmosphere by GHG sinks.
Reference: ISO 14068

Greenhouse Gas Reservoir

Anything, except the atmosphere, that has the capacity to accumulate GHGs. A GHG reservoir can store and release GHGs over time. The atmosphere is excluded as a reservoir in this context.
Reference: ISO 14068

Greenhouse Gas Sink

A process that removes GHGs from the atmosphere. A growing forest is a GHG sink.
Reference: ISO 14068

I

Indirect Emissions

There are two types of indirect emissions when accounting for GHG emissions. One type of indirect emissions occurs as a result of the generation of electricity or steam purchased (not generated on-site) and used in operations, buildings, or processes. These emissions are indirect because the emissions occur at facilities generating the electricity or steam, and are not generated by the end user. Under the Greenhouse Gas Protocol, indirect emissions fall within Scope 2. The other type of indirect emissions is the result of activities from assets not owned or controlled by the reporting organization, but which are within the organization’s value chain. These indirect emissions are considered Scope 3 emissions and include all sources not within an organization’s Scope 1 and Scope 2 boundary under the Greenhouse Gas Protocol’s definition. The Scope 3 emissions for one organization are the Scope 1 and 2 emissions of another organization. Indirect emissions often represent the majority of an organization’s total GHG emissions.
Reference: The Greenhouse Gas Protocol

Insetting

An action within an organization’s supply chain that results in lower GHG emissions or higher GHG sequestration. Insetting can take the form of a company making investments within their supply chain that lead to measurable and verifiable emissions reductions. This concept is also called a “supply chain intervention.” Insetting may become an effective tool for companies to reduce their Scope 3 emissions.
Reference: American Forest Foundation

Intergovernmental Panel on Climate Change (IPCC)

The IPCC was established jointly by the United Nations Environment Programme and the World Meteorological Organization in 1988. The purpose of the IPCC is to assess information in the scientific and technical literature related to all significant components of climate change. The IPCC draws upon hundreds of the world’s expert scientists as authors and thousands as expert reviewers. Leading experts on climate change and environmental, social, and economic sciences from some 60 nations have helped the IPCC to prepare periodic assessments of the scientific underpinnings for understanding global climate change and its consequences. With its capacity for reporting on climate change, its consequences, and the viability of adaptation and mitigation measures, the IPCC is considered the official advisory body to the world’s governments on the state of the science of the climate change issue.
Reference: The Intergovernmental Panel on Climate Change

K

Kyoto Protocol

The Kyoto Protocol operationalizes the United Nations Framework Convention on Climate Change (UNFCCC) by committing industrialized countries and economies in transition to limit and reduce GHG emissions following individual targets. The Kyoto Protocol was adopted on December 11, 1997, and entered into force on February 16, 2005. Currently, there are 192 Parties to the Kyoto Protocol with binding emission reduction targets for 37 industrialized countries and economies in transition.
Reference: UNFCCC

L

Land use, land-use change and forestry (LULUCF)

In the context of national greenhouse gas (GHG) inventories under the United Nations Framework Convention on Climate Change (UNFCCC 2019), LULUCF is a GHG inventory sector that covers anthropogenic emissions and removals of GHG in managed lands, excluding non-carbon dioxide (CO₂) agricultural emissions.
Reference: IPCC Expert Meeting on Reconciling Anthropogenic Land Use Emissions (2024)

N

Natural Climate Solutions

Actions to protect, better manage, and restore nature to reduce greenhouse gas emissions and store carbon.
Reference: Principles of Natural Climate Solutions

Negative Carbon Emissions

See Carbon Negative.

Net Zero

Often used synonymously with “carbon neutral.” Both “net zero” and “carbon neutral” mean balancing the amount of carbon released with an equivalent amount of carbon sequestered or offset. However, “net zero” is more comprehensive a term because it unambiguously includes all greenhouse gases. Net zero represents a condition in which metric-weighted anthropogenic greenhouse gas (GHG) emissions are balanced by metric-weighted anthropogenic GHG removals over a specified period. The quantification of net zero GHG emissions depends on the GHG emission metric chosen to compare emissions and removals of different gases, as well as the time horizon chosen for that metric.
References: IPCC 2021 Annex VII Glossary

O

Offsets

Offsets are verified GHG emissions reductions used to address direct and indirect emissions at additional, external projects. The unit of an offset is typically a metric ton of carbon dioxide equivalent (CO₂e) and simply called a carbon offset. Offsets are subtracted from organizational emissions to determine net organizational emissions. Offsetting is the process of generating or purchasing offsets. Offsets are a subset of avoided emissions by making the project the central component of emission reduction, whereas avoided emissions can also refer to a comparison of emissions not associated with a specific project.
Reference: The Greenhouse Gas Protocol

P

Paris Agreement

Currently the most geo-politically relevant international climate agreement adopted in 2015 with the central aim to hold global temperature rise in this century to well below 2°C above preindustrial levels and to pursue efforts to limit the temperature increase even further to 1.5°C. Under this agreement, all parties agreed to put forward emissions-reduction targets and to strengthen those efforts in the years ahead, as the agreement is assessed every five years. Each country’s proposed mitigation target (the “intended nationally determined contribution”) becomes an official “nationally determined contribution” when the country ratifies the agreement. Parties also agreed to adaptation efforts and finance mechanisms to support low greenhouse gas emissions and climate-resilient development.
Reference: Fifth U.S. National Climate Assessment
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R

Radiative Forcing

Radiative forcing is a measure of the influence of a particular factor (e.g., greenhouse gases, aerosol, or land use change) on the net change in the Earth’s energy balance.
Reference: Fifth U.S. National Climate Assessment
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Renewable Energy Certificate (REC)

Renewable Energy Certificates (RECs) are the legal instruments used in renewable electricity and thermal markets to account for renewable electricity and its attributes. RECs are verified by a third party and can be bought and sold between organizations. There are different types of RECs, mainly bundled and unbundled. Bundled RECs convey electricity and the energy attribute (e.g., carbon neutral) whereas unbundled RECs convey only the energy attribute (no actual electricity).
Reference: The Greenhouse Gas Protocol

Representative Concentration Pathways (RCP)

Representative Concentration Pathways (RCP) are computer-based scenarios that include time series of emissions and concentrations of GHGs, aerosols, other chemically active gases, and land use information. The word “representative” signifies that each RCP provides only one of many possible scenarios that would lead to the specific “concentration” (radiative forcing) characteristics. The term “pathway” emphasizes that not only the long-term concentration levels are of interest, but also the trajectory taken over time to reach that outcome.
Reference: Fifth U.S. National Climate Assessment
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Residual Greenhouse Gas Emissions

Greenhouse gas emissions remaining after achieving some GHG reductions. For example, if a company has a business as usual baseline of emitting 15,000 tons of carbon dioxide equivalent (CO₂e) per year and is able to remove 5,000 tons of CO₂e emissions through various activities, then residual emissions equal 10,000 tons of CO₂e per year.
Reference: ISO 14068

S

Scope 1

Scope 1 emissions are direct GHG emissions that occur from sources that are controlled or owned by the reporting organization (e.g., emissions associated with fuel combustion in boilers, furnaces, vehicles), as classified by the Greenhouse Gas Protocol Corporate Standard.
Reference: The Greenhouse Gas Protocol

Scope 2

Scope 2 emissions are indirect emissions from the generation of purchased energy, including electricity, steam, heat, or cooling, as classified by the Greenhouse Gas Protocol Corporate Standard.
Reference: The Greenhouse Gas Protocol

Scope 3

Scope 3 emissions are all indirect emissions (not included in Scope 2) that occur in the value chain of the reporting company, including both upstream and downstream emissions, as classified by the Greenhouse Gas Protocol Corporate Standard. Scope 3 emissions include all sources not within an organization’s Scope 1 and 2 boundary. Scope 3 emissions, also referred to as value chain emissions, can represent a large portion of an organization’s total GHG emissions.
Reference: The Greenhouse Gas Protocol

Substitution Effect

Greenhouse gas emissions that would be avoided if a wood-based product is used instead of another product to provide the same function.
Reference: The European Forest Institute

Substitution Factor

A substitution (or displacement) factor describes the GHG emissions that would be avoided if a wood-based product were used instead of another product to provide the same function. For example, using mass timber in a building to substitute for steel or concrete will result in avoided GHG emissions that can be expressed as a substitution factor.
Reference: Canadian Forest Service Pacific Forestry Centre

T

Tipping Point

The point at which a change in the climate triggers a significant environmental event, which may be permanent, such as widespread bleaching of ocean coral or the melting of very large ice sheets.
Reference: Fifth U.S. National Climate Assessment
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U

United Nations Framework Convention on Climate Change (UNFCCC)

The UN Convention on Climate Change entered into force on March 21, 1994, to set an overall framework for intergovernmental efforts to tackle challenges posed by climate change. The Convention enjoys near universal membership, with 189 countries having ratified it. Under the Convention, governments: 1) gather and share information on greenhouse gas emissions, national policies, and best practices; 2) launch national strategies for addressing GHG emissions and adapting to expected impacts; and 3) cooperate in preparing for adaptation to the impacts of climate change.
Reference: UNFCCC