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LiveSmart BC

LiveSmart BC Climate Glossary


Absolute emissions target: “a fixed number of tons of CO2 equivalent, to be achieved at some point in the future (usually expressed as a change relative to a base year that has a known quantity)” (WRI, Target: Intensity1)

Adaptation: Changing behaviour to adjust to the predicted changes in the natural environment due to climate change. Adjustment in natural or human systems in response to actual or expected climatic stimuli or their effects, which moderates harm or exploits beneficial opportunities”. Adaptation can include changes in behaviour, technology, institutions, policies, and other aspects of human systems(IPCC2)

Additionality: “Emissions reductions achieved through a given project over and above those that would otherwise have occurred in the absence of the project under a business-as-usual scenario. Additionality is a criterion for approval of project-based activities under the Clean Development Mechanism of the Kyoto Protocol as well as for offset projects allowed for credit under emissions trading programs”. (CARB3)

Afforestation: Planting trees where none existed before. The process of establishing and growing forests on bare or cultivated land, which has not been forested in recent history” (World Bank). Article 3.3 of the Kyoto Protocol limits afforestation to activities since 1990. (CARB)

Allocation: “The process by which emissions allowances are initially distributed under an emissions cap and trade system. Authorizations to emit can initially be distributed in a number of ways. See “auctioning,” “benchmarking,” “grandfathering,” and “updating.”” (CARB)

Allowance: “A government issued authorization to emit a certain amount. In greenhouse gas markets, an allowance is commonly denominated as one ton of CO2e per year. See also “permit” and “credits (a.k.a. carbon credits).” The total number of allowances allocated to all entities in a cap and trade system is determined by the size of the overall cap on emissions.” (CARB)

Annex I Countries/Parties: “Group of countries included in Annex I (as amended in 1998) to the United Nations Framework Convention on Climate Change (UNFCCC), including all the developed countries in the Organization of Economic Co-operation and Development, and economies in transition. By default, the other countries are referred to as Non-Annex I countries. Under Articles 4.2 (a) and 4.2 (b) of the Convention, Annex I countries commit themselves specifically to the aim of returning individually or jointly to their 1990 levels of greenhouse gas emissions.” (CARB)

Anthropogenic emissions: Human-caused emissions of greenhouse gas emissions. “Emissions of greenhouse gases, greenhouse gas precursors, and aerosols associated with human activities. These include burning of fossil fuels (coal, oil and natural gas) for energy, deforestation, and land-use changes that result in net increase in emissions” (IPCC).

Atmosphere: The layer of gases surrounding Earth. It is about 480 kilometres thick, and mainly composed of nitrogen, oxygen, carbon dioxide, and a few other trace gases.

Auctioning: “A method for distributing emission allowances in a cap and trade system whereby allowances are sold to the highest bidder. This method of allocation may be combined with other forms of allowance allocation.” (CARB)


Banking: “The carry-over of unused allowances or offset credits from one compliance period to the next”. (CARB)

Baseline: “A hypothetical scenario for what GHG emissions, removals or storage would have been in the absence of the GHG project or project activity.” (GHG Protocol)4 It is often used to measure GHG emission reductions or removals from an offset project, which are determined as the difference between actual emissions and the baseline scenario.

Base year emissions: GHG emissions in a specified (usually historical) year, against which future emissions are measured. Emission targets are often defined relative to base year emissions, e.g. 10% below 1990 emission levels.

Benchmarking: “An allowance allocation method in which allowances are distributed by setting a level of permitted emissions per unit of input or output.” (CARB)


Cap: A mandated restraint in a scheduled timeframe that puts a "ceiling" on the total amount of anthropogenic greenhouse gas emissions that can be released into the atmosphere. This can be measured as gross emissions or as net emissions (emissions minus gases that are sequestered).

Cap and trade system : “A system designed to limit and reduce emissions. Cap and trade regulation creates a single market mechanism as opposed to a command and control approach that prescribes reductions on a source-by-source basis. Cap and trade regulation sets an overall limit on emissions and allows entities subject to the system to comply by undertaking emission reduction projects at their covered facilities and/or by purchasing emission allowances (or credits) from other entities that have generated emission reductions in excess of their compliance obligations.” (CARB)

Carbon: Carbon (C) is the building block of life. It is the basic element in all living things, including 50% of the dry weight in the human body. In the form of carbon dioxide, carbon is a powerful greenhouse gas. However, the term "carbon" used in discussing climate change does not just to refer to carbon dioxide. It includes the other powerful greenhouse gases, such as methane and nitrous oxide. Scientists are able to lump these six gases together under the name "carbon" by figuring out their carbon dioxide equivalent. So when we talk about "carbon footprint" and "carbon neutral," for example, we are referring to all the major greenhouse gases, not just carbon dioxide.

Carbon Dioxide (CO2): A colourless, odourless gas. It is formed during breathing, combustion, and decaying of organic materials. It occurs naturally (0.03% of atmosphere) and is also a by-product of burning fossil fuels and biomass, land-use changes, and other industrial processes. It is the principal anthropogenic greenhouse gas. It is the reference gas against which other greenhouse gases are measured and therefore has a Global Warming Potential of 1. (IPCC)

Carbon Dioxide Equivalent (CO2e): “The universal unit of measurement to indicate the global warming potential (GWP) of each of the six greenhouse gases, expressed in terms of the GWP of one unit of carbon dioxide.” (GHG Protocol) Expressing all GHGs in terms of tonnes of CO2e allows the different gases to be aggregated (grouped together).

Carbon Footprint: The total amount of greenhouse gases produced by human activities. This is usually expressed in equivalent tonnes of carbon dioxide (CO2), which is the major greenhouse gas. For example, when we burn fossil fuels to run our vehicles or heat our homes, we are releasing carbon dioxide. The food we buy gets to the grocery store by motor vehicle, and possibly train or plane, which emit CO2. Our carbon footprint is the sum of the CO2 emissions caused by our activities, usually calculated over a year.

Carbon Intensity: “The relative amount of carbon emitted per unit of energy or fuels consumed” (IPCC).  A Low Carbon Fuel Standard would set limits on the carbon intensity of fuels, measured in grams per gigajoule.

Carbon Neutral: Being carbon neutral refers to maintaining a balance between producing and using carbon. For example, we release carbon dioxide when we burn fossil fuels in vehicles. We can balance out those emissions by planting trees because vegetation absorbs carbon dioxide. There are many ways governments, industry and individuals can work towards being carbon neutral. An organization is carbon neutral if it has (1) calculated the total emissions for which it is responsible, (2) pursued actions to minimize those emissions, and (3) applied emissions offsets to net those emissions to zero.

Carbon Sink: Processes that remove more carbon dioxide from the atmosphere than they release, as part of the carbon cycle. For example, forests and oceans act as carbon sinks. Forests can be planted specifically for this purpose, which is called carbon sequestration.

Carbon sequestration: The process of increasing the carbon stored in a reservoir other than the atmosphere.  Biological approaches to sequestration include direct removal of carbon dioxide from the atmosphere through land-use change, afforestation, reforestation, and practices that enhance soil carbon in agriculture. This removal is considered temporary as the carbon dioxide returns to the atmosphere when plants die or are burned. Physical approaches include separation and disposal of carbon dioxide from flue gases or from processing fossil fuels to produce hydrogen- and carbon dioxide-rich fractions and long-term storage in underground in depleted oil and gas reservoirs, coal seams, and saline aquifers.” (IPCC)

Carbon Tax: A surcharge on the carbon content of oil, coal, and gas that discourages the use of fossil fuels and aims to reduce carbon dioxide emissions. B.C. introduced a carbon tax that is revenue neutral, meaning all revenue generated by the tax will be returned to individuals and businesses through reductions in other taxes.

Clean Development Mechanism (CDM): “One of the three market mechanisms established by the Kyoto Protocol to provide flexibility for compliance. The CDM is designed to promote sustainable development in developing countries and assist Annex I Parties in meeting their greenhouse gas emission reduction commitments. It enables industrialized countries to invest in emission reduction projects in developing countries and to share credits for the GHG reductions achieved.” (CARB)

Climate: “The long-term statistical average of weather-related aspects of a region including typical weather patterns, the frequency and intensity of storms, cold spells, and heat waves. Climate is not the same as weather. A description of the climate of a certain place would include the averages and extremes of such things as temperature, rainfall, humidity, evapotranspiration and other variables that can be determined from past weather records during a specified interval of time.” (CARB)

(Global) Climate Change: “Refers to changes in long-term trends in the average climate, such as changes in average temperatures.”(CARB)

Climate System: Involves the natural reactions between the gases in the atmosphere, the planet’s water, ice, the land and living things, and solar energy. Together, they determine the earth's climate.

Command and Control: “A system of regulation that prescribes emission limits and compliance methods on a facility-by-facility or source-by-source basis and that has been the traditional approach to reducing air pollution.” (CARB)

Chlorofluorocarbons (CFCs): “Gaseous, synthetic substances composed of chlorine, fluorine and carbon. CFCs have been used as refrigerants, aerosol propellants, and cleaning solvents, and in the manufacture of plastic foam. As well as causing ozone depletion in the stratosphere, CFCs are greenhouse gases. Their use is being phased out under the Montreal Protocol. Some of their replacements are "ozone-friendly" but are, nonetheless, potent greenhouse gases.” (CARB)

Credits (a.k.a. carbon credits): “Credits can be distributed by the government for reductions achieved by offset projects or by achieving environmental performance beyond a regulatory standard.” (CARB)


Deforestation: The direct human-induced conversion of forested land to non-forested land.


Emissions: “The release of substances (e.g. greenhouse gases) into the atmosphere. Emissions occur both through natural processes and as a result of human activities.” (CARB)

Emissions Cap: “A mandated constraint in a scheduled timeframe that puts a "ceiling" on the total amount of anthropogenic greenhouse gas emissions that can be released into the atmosphere.” (CARB)

Emission Factor: “A factor allowing GHG emissions to be estimated from a unit of available activity data (e.g. tonnes of fuel consumed, tonnes of product produced) and absolute GHG emissions” (GHG Protocol)

Emission Offset: Offsets are voluntary project-based emission reductions or removals that are used to meet voluntary or regulatory emission reduction obligations.  Offset programs usually establish a number of specific eligibility criteria, and often require that offsets be real, quantifiable, verifiable or verified, surplus or additional, permanent and unique. “Offsets are calculated relative to a baseline that represents a hypothetical scenario for what emissions would have been in the absence of the mitigation project that generates the offsets.” (GHG Protocol)

Emission Reductions (ERs): “The measurable reduction of release of greenhouse gases into the atmosphere from a specified activity or over a specified area, and a specified period of time” (World Bank)

Emissions trading: “The process or policy that allows the buying and selling of credits or allowances created under an emissions cap.” (CARB)
A market mechanism that allows emitters (countries, companies or facilities) to buy emissions from or sell emissions to other emitters. Emissions trading is expected to bring down the costs of meeting emission targets by allowing those who can achieve reductions less expensively to sell excess reductions (e.g. reductions in excess of those required under some regulation) to those for whom achieving reductions is more costly.

Energy: The fundamental substance of everything in the universe. When we are talking about the environment, energy is the power we get from burning fossil fuels; electricity; and nuclear power — along with the more green options such as solar and wind power.

Energy Conservation: Cutting down on energy use to reduce emissions caused by such energy-generating processes as the combustion of fossil fuels and wood, and power plants.

European Union Emissions Trading Scheme (EU ETS): “The world’s largest greenhouse gas emissions trading system is the European Union’s Emissions Trading Scheme, which limits CO2 emissions from 12,000 facilities in the 25 EU member states. Launched in 2005, the ETS covers electricity and major industrial sectors (including oil, iron and steel, cement, and pulp and paper) that together produce nearly half the EU’s CO2 emissions. ETS rules are set at the regional level but decisions on emission allowance allocation are left to member states. An initial phase runs through 2007; a second will coincide with the Kyoto Protocol compliance period (2008-2012). Excess emissions incur a penalty (100 Euros/ton in phase II) and must be made up in the next phase. EU policymakers have said the ETS will continue beyond 2012 with or without new international climate agreements.” (CARB)


Global Warming: The trend of rising Earth's average surface temperature caused predominantly by increased concentrations of GHGs in the atmosphere. Strictly speaking, global warming refers only to warming trends. However, the term "global warming" has become a popular term encompassing all aspects of climate change, including, for example, the potential changes in precipitation that will be brought about by an increase in global temperatures. The term is used interchangeably with the term, "climate change." (CARB)

Global Warming Potential (GWP): “Greenhouse gases differ in their effect on the Earth’s radiation balance depending on their concentration, residence time in the atmosphere, and physical properties with respect to absorbing and emitting radiant energy. By convention, the effect of carbon dioxide is assigned a value of one (1) (i.e., the GWP of carbon dioxide =1) and the GWPs of other gases are expressed relative to carbon dioxide. For example, in the U.S. national inventory, the GWP of nitrous oxide is 310 and that of methane 21, indicating that a tonne of nitrous oxide has 310 times the effect on warming as a ton of carbon dioxide. Slightly different GWP values for greenhouse gases have been estimated in other reports. Some industrially produced gases such as sulfur hexafluoride (SF6), perfluorocarbons (PFCs), and hydrofluorocarbons (HFCs) have extremely high GWPs. Emissions of these gases have a much greater effect on global warming than an equal emission (by mass) of the naturally occurring gases. Most of these gases have GWPs of 1,300 - 23,900 times that of CO2. The US and other Parties to the UNFCCC report national greenhouse gas inventories using GWPs from the IPCC's Second Assessment Report (SAR). SAR GWPs are also used for the Kyoto Protocol and the EU ETS. GWPs indicated in this document also refer to the IPCC’s Second Assessment Report.” (CARB)

Grandfathering: “A method by which emission allowances are freely distributed to entities covered under an emissions trading program based on historic emissions.” (CARB)

Greenhouse Effect: “The heat-trapping effect of atmospheric greenhouse gases (e.g., water vapor, carbon dioxide, methane, etc.) that keeps the Earth's temperature about 60°F warmer than it would be otherwise. These gases absorb infra-red radiation emitted by the Earth and retard the loss of energy from the Earth system into space. The natural greenhouse effect has been a property of Earth’s atmosphere for millions of years and is responsible for maintaining the Earth’s surface at a temperature that makes it habitable for human beings. The Earth is currently experiencing an enhanced greenhouse effect due to an increase in atmospheric concentrations of greenhouse gases emitted by human activities.” (CARB)

Greenhouse gases (GHGs): “Greenhouse gases include a wide variety of gases that trap heat near the Earth’s surface, slowing its escape into space. Greenhouse gases include carbon dioxide, methane, nitrous oxide and water vapor and other gases. While greenhouse gases occur naturally in the atmosphere, human activities also result in additional greenhouse gas emissions. Humans have also manufactured some gaseous compounds not found in nature that also slow the release of radiant energy into space.” (CARB)

Gross CO2 emissions: The total greenhouse gas emissions (measured in CO2e) in a given period and specific area or region that does not include sinks of greenhouse gas emissions in that area or region.


Hydrofluorocarbons (HFCs): “One of the six primary GHGs. Synthetic industrial gases, primarily used in refrigeration and other applications as commercial substitutes for chlorofluorocarbons (CFCs). There are no natural sources of HFCs. The atmospheric lifetime of HFCs is decades to centuries, and they have "global warming potentials" thousands of times that of CO2, depending on the gas. HFCs are among the six greenhouse gases to be curbed under the Kyoto Protocol.” (CARB)


Indicators: Measuring sticks that track the results achieved by governments, industries and individuals to protect and improve the environment.

Intensity-Based Target: “Intensity targets are expressed as emissions per unit of output (e.g., GDP, physical production). An intensity target seeks to achieve a particular emissions rate, or level of performance, rather than a specific level of emissions” (WRI, Target: Intensity)

Intergovernmental Panel on Climate Change (IPCC): “Recognizing the problem of potential global climate change, the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) established the Intergovernmental Panel on Climate Change (IPCC) in 1988. It is open to all members of the UN and WMO. The role of the IPCC is to assess on a comprehensive, objective, open and transparent basis the scientific, technical and socio-economic information relevant to understanding the scientific basis of risk of human-induced climate change, its potential impacts and options for adaptation and mitigation. The IPCC does not carry out research nor does it monitor climate related data or other relevant parameters. It bases its assessment mainly on peer reviewed and published scientific/technical literature.” (CARB)

Inventory: “A greenhouse gas inventory is an accounting of the amount of greenhouse gases emitted to or removed from the atmosphere over a specific period of time (e.g., one year). A greenhouse gas inventory also provides information on the activities that cause emissions and removals, as well as background on the methods used to make the calculations. Policy makers use greenhouse gas inventories to track emission trends, develop strategies and policies and assess progress. Scientists use greenhouse gas inventories as inputs to atmospheric and economic models” (CARB)

IPCC Guidelines: The IPCC Guidelines for National Greenhouse Gas Inventories provide internationally accepted methodologies for estimating national inventories of anthropogenic emissions by sources and removals by sinks of greenhouse gases. The IPCC Guidelines were prepared in response to an invitation by the Parties to the UNFCCC, for fulfilling their commitments under the UNFCCC on reporting on inventories of anthropogenic emissions by sources and removals by sinks of greenhouse gases not controlled by the Montreal Protocol.” (CARB)


Joint Implementation (JI): “A mechanism under the Kyoto Protocol through which a developed country can receive "emissions reduction units" (ERUs) when it helps to finance projects that reduce net greenhouse gas emissions in another developed country (in practice, the recipient state is likely to be a country with an "economy in transition"). An Annex I Party must meet specific eligibility requirements to participate in joint implementation.” (CARB)


Kyoto Mechanisms: “Three procedures established under the Kyoto Protocol to increase the flexibility and reduce the costs of reducing greenhouse-gas emissions; they are the Clean Development Mechanism (CDM), emissions trading, and joint implementation (JI).” (CARB)

Kyoto Protocol: “An international agreement signed at the Third Conference of the Parties to the UN Framework Convention on Climate Change in Kyoto, Japan (December 1997). The Protocol sets binding emission targets for industrialized countries that would reduce their collective emissions by 5.2 percent, on average, below 1990 levels by 2012.” (CARB)


Leakage: “Leakage occurs when activities that reduce greenhouse gas emissions (or increase carbon in plants and soils) in one place and time result in increases of emissions (or loss of soil or plant carbon) elsewhere or at later times. For example, a steel firm in a country covered by the Kyoto Protocol makes reductions by closing one facility and replacing its output with production from a steel plant operating in another country that does not have a GHG constraint. Similarly, a forest can be protected in one location and cause harvesting of forests elsewhere.” (CARB)


Methane (CH4): A colorless, odourless gas. Also known as Natural Gas. “One of the six greenhouse gases to be curbed under the Kyoto Protocol. Atmospheric CH4 is produced in nature, but human related sources such as landfills, livestock feedlots, natural gas and petroleum systems, coal mines, rice fields, and wastewater treatment plants also generate substantial CH4 emissions. CH4 has a relatively short atmospheric lifetime of approximately 10 years, but its 100-year GWP is currently estimated to be approximately 21 times that of CO2.” (CARB)

Metric Ton (tonne): Standard “measurement for the quantity of GHG emissions, equivalent to about 2,204.6 pounds or 1.1 short tons”. (California Climate Action Registry)

Mitigation: In the context of climate change, a human intervention to reduce the sources or enhance the sinks of greenhouse gases.  Examples include: using fossil fuels more efficiently for industrial processes or electricity generation, switching from oil to natural gas as a heating fuel, improving the insulation of buildings, and expanding forests and other "sinks" to remove greater amounts of carbon dioxide from the atmosphere. (UNFCC5)


Net CO2e emissions: Difference between sources and sinks of greenhouse gas emissions (measured in CO2e) in a given period and specific area or region.

Nitrous Oxide (N2O): A colourless gas with a slightly sweet odour (also called "laughing gas"). “One of the six greenhouse gases to be curbed under the Kyoto Protocol. N2O is produced by natural processes, but substantial emissions are also produced by such human activities as farming and fossil fuel combustion. The atmospheric lifetime of N2O is approximately 100 years, and its 100-year GWP is currently estimated to be 310 times that of CO2.” (CARB)


Offset: Offsets are project-based emission reductions or removals that are used to meet voluntary or regulatory emission reduction obligations. Offset programs usually establish a number of specific eligibility criteria, and often require that offsets be real, quantifiable, verifiable or verified, surplus or additional, permanent and unique.
“Projects undertaken outside the coverage of a mandatory emissions reduction system for which the ownership of verifiable GHG emission reductions can be transferred and used by a regulated source to meet its emissions reduction obligation. If offsets are allowed in a cap and trade program, credits would be granted to an uncapped source for the emissions reductions a project (or plant or soil carbon sink) achieves. A capped source could then acquire these credits as a method of compliance under a cap.” (CARB)


Perfluorocarbons (PFCs): “PFCs are among the six greenhouse gases to be curbed under the Kyoto Protocol. PFCs are synthetic industrial gases generated as a by-product of aluminum smelting and uranium enrichment. They also are used in the manufacture of semiconductors. There are no natural sources of PFCs. PFCs have atmospheric lifetimes of thousands to tens of thousands of years and 100-year GWPs thousands of times that of CO2, depending on the specific PFC.” (CARB)

Point of Regulation: “The point of program enforcement, or where specific emitting entities covered under a cap and trade program are required to surrender enough allowances to match their actual emissions within a compliance period.” (CARB)


Radiative forcing: “the difference between the incoming radiation energy and the outgoing radiation energy in a given climate system. A positive forcing (more incoming energy) tends to warm the system, while a negative forcing (more outgoing energy) tends to cool it” (wikipedia- IPCC’s definition was not English)

Reforestation: Planting of forests on lands that have recently previously contained forests but that have been converted to some other use. Article 3.3 of the Kyoto Protocol limits reforestation to planting forests on lands that have not been forested since 1990.

Regional Greenhouse Gas Initiative (RGGI): “The Regional Greenhouse Gas Initiative (RGGI) is establishing the first mandatory U.S. cap and trade program for carbon dioxide, and currently includes ten Northeastern and mid-Atlantic states. The governors of Connecticut, Delaware, Maine, New Hampshire, New Jersey, New York, and Vermont established RGGI in December 2005. Massachusetts, Rhode Island and Maryland joined in early 2007. Additional states can join the program with the agreement of the participating states. RGGI sets a cap on carbon dioxide emissions from power plants and allows sources to trade emission allowances. The program will cap emissions at current levels in 2009 and then reduce emissions 10% by 2019. Each state that intends to participate in RGGI must adopt a model rule through legislation or regulation and determine how to distribute emissions allowances. Member states agree to set aside at least 25% of their emission allowances for public benefit.” (CARB)

Registries, registry systems: “Electronic databases that track and record emissions and emission allowance holdings, retirements, cancellations and transfers.” (CARB)

Reservoir: “A component of the climate system, other than the atmosphere, which has the capacity to store, accumulate, or release” carbon or a greenhouse gas. “Oceans, soils, and forests are examples of reservoirs of carbon.”  (IPCC)


Sink: “Any process, activity or mechanism that removes a greenhouse gas from the atmosphere to a reservoir.”  (IPCC)

Source: “Any process, activity, or mechanism that releases a greenhouse gas emissions.”  (IPCC)

Stock: “The absolute quantity of substance of concern, held within a reservoir at a specified time, is called the stock. The term also means an artificial or natural storage place for water, such as a lake, pond, or aquifer, from which the water may be withdrawn for such purposes as water supply or irrigation” (IPCC)

Sulfur Hexafluoride (SF6): One of the six greenhouse gases to be curbed under the Kyoto Protocol. SF6 is a synthetic industrial gas largely used in heavy industry to insulate high-voltage equipment and to assist in the manufacturing of cable-cooling systems. There are no natural sources of SF6. SF6 has an atmospheric lifetime of 3,200 years. Its 100-year GWP is currently estimated to be 22,200 times that of CO2.” (CARB)


United Nations Framework Convention on Climate Change (UNFCCC): The Convention was adopted on 9 May 1992 in New York and signed at the 1992 Earth Summit in Rio de Janeiro by more than 150 countries and the European Community. Its objective is the “stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.” It contains commitments for all Parties. Under the Convention, Parties included in Annex 1 aimed to reduce greenhouse gas emissions. The Convention entered into force in March 1994. (IPCC)


Verification: “The act of checking or testing, by an independent and certified party, to ensure that an emission reduction project actually achieves emission reductions commensurate with the credits it receives.” (CARB)


Western Climate Initiative (WCI): A collaboration launched in February 2007 to meet regional challenges raised by climate change. WCI is identifying, evaluating and implementing collective and cooperative ways to reduce greenhouse gases in the region. Membership in the WCI presently consists of six U.S. states (Arizona, California, New Mexico, Oregon, Utah and Washington State) and two Canadian provinces (BC and Manitoba). The partners set an overall regional goal in August 2007 for reducing greenhouse gas emissions, and by August 2008 they will complete the design of a market-based mechanism to help achieve that reduction goal. (WCI6)


  1. Herzog, Timothy, Kevin A Baumert and Jonathan Pershing “Target: Intensity. An Analysis of Greenhouse Gas Intensity Targest.” World Resources Institute.
  2. Glossary of Terms used in the IPCC Third Assessment Report.
  3. Market Advisory Committee to the California Air Resources Board. “Recommendations for Designing a Greenhouse Gas Cap-and-Trade System for California.” June 30, 2007.
  4. World Business Council for Sustainable Development and World Resources Institute. GHG Protocol: “Corporate Accounting and Reporting Standards.”
  5. United Nations Framework Convention on Climate Change. “Glossary of climate change acronyms”
  6. Western Climate Initiative. “About WCI.”

Frequently Asked Questions (FAQs)

What are Greenhouse Gases (GHGs)?
Greenhouse gases absorb and emit radiation at specific wavelengths within the spectrum of infrared radiation emitted by the Earth's surface, the atmosphere, and clouds. This property causes the greenhouse effect. Water vapor (H2O), carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4), and ozone (O3) are the primary greenhouse gases in the Earth's atmosphere. Moreover there are a number of entirely human-made greenhouse gases in the atmosphere, such as the halo carbons and other chlorine- and bromine-containing substances, dealt with under the Montreal Protocol. Besides CO2, N2O, and CH4, the Kyoto Protocol deals with the greenhouse gases sulfur hexafluoride (SF6), hydro fluorocarbons (HFCs), and per fluorocarbons (PFCs). (IPCC)

What is Carbon Dioxide (CO2)?
CO2 is a natural occurring gas that is a by-product of burning fossil fuels and biomass, land-use changes and other industrial processes.  It is the principal anthropogenic (human caused) greenhouse gas that affects the Earth’s radiative balance. It is the reference gas against which other greenhouse gases are measured and, therefore, has a Global Warming Potential of 1. (IPCC)

What is Carbon Dioxide Equivalent (CO2e)?
CO2e is the universal unit of measurement to indicate the global warming potential (GWP). Out of each of the six greenhouse gases, it is expressed in terms of the GWP of one unit of carbon dioxide. It is used to evaluate releasing (or avoiding releasing) different greenhouse gases against a common basis. (GHG Protocol)

How big is one tonne of CO2?
Greenhouse gases are generally measured in terms of their mass because their volume varies with temperature and pressure. But, if we were to measure them in terms of volume, at sea level and at an ambient temperature of 18°C, one tonne of CO2 would fill an average two-storey, three-bedroom house.

What is Climate Change?
“Climate change” can mean a change in climate due to natural or human (anthropogenic) causes. Increasingly, the term has come to refer specifically to that part of climate variation resulting from human-induced greenhouse gas emissions. Thus, the United Nations Framework Convention on Climate Change, 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.

What are Emissions (GHG)?
Emissions are the release of GHG into the atmosphere. (GHG Protocol)

What is an Emission Factor?
A factor allowing GHG emissions to be estimated from a unit of available activity data (e.g., tonnes of fuel consumed, tonnes of product produced) and absolute GHG emissions. (GHG Protocol)

What are Emission Reductions (ERs)?
ERs are the measurable reduction of release of greenhouse gases into the atmosphere from a specified activity or over a specified area, and a specified period of time. (World Bank)