Working Group III: Mitigation

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Economic potential
Economic potential is the portion of technological potential for greenhouse gas emissions reductions or energy efficiency improvements that could be achieved cost-effectively through the creation of markets, reduction of market failures, increased financial and technological transfers. The achievement of economic potential requires additional policies and measures to break down market barriers. See also market potential, socio-economic potential, and technological potential.

Economies in transition (EITs)
Countries with national economies in the process of changing from a planned economic system to a market economy.

A system of interacting living organisms and their physical environment. The boundaries of what can be called an ecosystem are somewhat arbitrary, depending on the focus of interest or study. Thus, the extent of an ecosystem may range from very small spatial scales to, ultimately, the entire earth.

See emissions tax

See economies in transition.

In the climate change context, emissions refer to the release of greenhouse gases and/or their precursors and aerosols into the atmosphere over a specified area and period of time.

Emissions 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. The Kyoto Protocol mandates caps on the greenhouse gas emissions released by Annex B countries/Parties.

Emissions factor
An emissions factor is the coefficient that relates actual emissions to activity data as a standard rate of emission per unit of activity.

Emissions permit
An emissions permit is the non-transferable or tradable allocation of entitlements by a government to an individual firm to emit a specified amount of a substance.

Emissions quota
The portion or share of total allowable emissions assigned to a country or group of countries within a framework of maximum total emissions and mandatory allocations of resources.

Emissions reduction unit (ERU)
Equal to 1 tonne (metric ton) of carbon dioxide emissions reduced or sequestered arising from a Joint Implementation (defined in Article 6 of the Kyoto Protocol) project, calculated using Global Warming Potential. See also certified emission reduction and emissions trading.

Emission standard
A level of emission that under law or voluntary agreement may not be exceeded.

Emissions tax
Levy imposed by a government on each unit of CO2-equivalent emissions by a source subject to the tax. Since virtually all of the carbon in fossil fuels is ultimately emitted as carbon dioxide, a levy on the carbon content of fossil fuels – a carbon tax – is equivalent to an emissions tax for emissions caused by to fossil fuel combustion. An energy tax – a levy on the energy content of fuels – reduces demand for energy and so reduces carbon dioxide emissions from fossil fuel use. An ecotax is designated for the purpose of influencing human behaviour (specifically economic behaviour) to follow an ecologically benign path. International emissions/carbon/energy tax is a tax imposed on specified sources in participating countries by an international agency. The revenue is distributed or used as specified by participating countries or the international agency.

Emissions trading
A market-based approach to achieving environmental objectives that allows those reducing greenhouse gas emissions below what is required to use or trade the excess reductions to offset emissions at another source inside or outside the country. In general, trading can occur at the intracompany, domestic, and international levels. The Second Assessment Report by the Intergovernmental Panel on Climate Change adopted the convention of using “permits” for domestic trading systems and “quotas” for international trading systems. Emissions trading under Article 17 of the Kyoto Protocol is a tradable quota system based on the assigned amounts calculated from the emission reduction and limitation commitments listed in Annex B of the Protocol. See also certified emission reduction and Clean Development Mechanism.

Energy conversion
See energy transformation.

Energy efficiency
Ratio of energy output of a conversion process or of a system to its energy input.

Energy intensity
Energy intensity is the ratio of energy consumption to economic or physical output. At the national level, energy intensity is the ratio of total domestic primary energy consumption or final energy consumption to Gross Domestic Product or physical output.

Energy service
The application of useful energy to tasks desired by the consumer such as transportation, a warm room, or light.

Energy Tax
See emissions tax.

Energy transformation
The change from one form of energy, such as the energy embodied in fossil fuels, to another, such as electricity.

Equivalent CO2
See CO2-equivalent.

See emissions reduction unit.

See external cost.

External cost
Used to define the costs arising from any human activity, when the agent responsible for the activity does not take full account of the impacts on others of his or her actions. Equally, when the impacts are positive and not accounted for in the actions of the agent responsible they are referred to as external benefits. Emissions of particulate pollution from a power station affect the health of people in the vicinity, but this is not often considered, or is given inadequate weight, in private decision making and there is no market for such impacts. Such a phenomenon is referred to as an externality, and the costs it imposes are referred to as the external costs.

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