Other terms
Emission sources, removal sinks
A source is any process or activity that releases a greenhouse gas, an aerosol, or a precursor of a greenhouse gas into the atmosphere. This release is called an emission. A sink is a reservoir that uptakes a greenhouse gas from another part of its cycle. Soil and trees tend to act as natural sinks for carbon. This uptake is called a removal.
Anthropogenic
Man-made, resulting from human activities. In the IPCC Guidelines, anthropogenic emissions are distinguished from natural emissions. Many greenhouse gases are emitted naturally. It is only the man-made increments over natural emissions which may be perturbing natural balances.
Activity Data
Data on the magnitude of human activity resulting in emissions or removals taking place during a given period of time. In the energy sector for example, the annual activity data for fuel combustion sources are the total amounts of fuel burned. Annual activity data for methane emissions from enteric fermentation are the total number of animals being raised, by species.
Emission Factor
A coefficient that relates the activity data to the amount of chemical compound which is the source of later emissions. Emission factors are often based on a sample of measurement data, averaged to develop a representative rate of emission for a given activity level under a given set of operating conditions.
Default Methodology
In the Revised 1996 IPCC Guidelines and the IPCC Good Practice Guidance (including LULUCF Good Practice Guidance), the default methodology is usually referred to as the Tier 1 method. It is normally the most basic method available for estimating emissions or removals from a particular source or sink category. It often relies on default emission factors and other data and is usually considered to be more uncertain than higher Tier methods.
Base Year
The year 1990 should be the base year for the estimation and reporting of inventories by Annex I Parties. According to the provisions of Article 4.6 of the United Nations Convention on Climate Change and decisions 9/CP.2 and 11/CP.4, the following Annex I Parties that are undergoing the process of transition to a market economy are allowed to use a base year or a period of years other than 1990, as follows:
Bulgaria: 1988
Hungary: the average of the years 1985 to 1987
Poland: 1988
Romania: 1989
Slovenia: 1986
Implied Emission Factor (IEF)
A calculated value based on aggregate activity data and emission estimates provided by a Party in its national inventory submission. Standard implied emission factors have been defined for various categories and are used to compare indexed (i.e., normalized) emissions between Parties, specifically in the Synthesis and Assessment stage of the UNFCCC annual inventory review process.
Click here to see an example table using IEFs.
Implied Carbon-Stock-Change Factor
A calculated value based on aggregate activity data and carbon stock estimates provided by a Party in its national inventory submission. Standard implied carbon-stock-change factors have been defined for various land types and land-use change categories and are used to compare indexed (i.e., normalized) carbon-stock-changes (emissions or removals) between Parties, specifically in the Synthesis and Assessment stage of the UNFCCC annual inventory review process.
Click here to see an example table using Implied Carbon-Stock-Change Factors.