Appendix C — Glossary of Terms

Activity Data: Data on the magnitude of a human activity that results in emissions or removals during a given period of time.
Anaerobic: Conditions in which oxygen is not readily available. These conditions matter for the production of methane, because organic material that decomposes without oxygen, as in a landfill or a flooded rice field, is likely to form methane.
Andosol: A soil developed in volcanic ash. Andosols generally drain well and are prone to fertility problems.
Bootstrap Technique: A computationally intensive statistical method that repeatedly resamples a set of data to assess the variability of parameter estimates.
Back-casting: The opposite of forecasting, in that past conditions are predicted from current conditions.
Bias: A systematic error of the observation method, whose magnitude in most cases is unknown. It can arise from measuring equipment that is improperly calibrated, from selecting items from the wrong population, or from favouring certain elements of a population.
Carbon Dioxide Equivalent: (CO₂e) A measure used to compare different greenhouse gases by their contribution to radiative forcing. The UNFCCC currently uses global warming potentials (GWPs) as the factors for calculating carbon dioxide equivalent.
Coefficient of Variation: The ratio of the population standard deviation, $\sigma_x$, to the mean, $\mu_x$, where $v_x = \sigma_x / \mu_x$. It is often used to express the standard deviation as a percentage of the mean.
Confidence Interval: The range that encloses the true value of an unknown fixed quantity with a specified confidence. A 95 per cent confidence interval is typically assumed, and the ART-TREES Standard requires 90 per cent.
Decision Tree: A flow chart describing the ordered steps that must be followed to develop an inventory, or a component of one, in line with the principles of good practice.
Emission Factor: A coefficient that quantifies the emissions or removals of a gas per unit of activity. Emission factors are often based on a sample of measurements, averaged to give a representative rate of emission for a given activity level under a given set of operating conditions.
Global Warming Potentials: (GWP) The ratio of the radiative forcing of one kilogram of a greenhouse gas emitted to the atmosphere to that of one kilogram of CO2 over a period of time, such as 100 years.
Ground Truth: Data obtained by measurement on the ground, usually to validate remote sensing data such as satellite imagery.
Monte Carlo Method: ¹ The statistical method recommended for analysing the uncertainty of the inventory. It performs the inventory calculation many times by computer, each time with the uncertain emission factors or model parameters and activity data drawn at random from the distributions of uncertainty specified by the user.
Normal Distribution: A probability distribution, also called the Gaussian distribution, defined by two parameters, the mean ($\mu$) and the standard deviation ($\sigma$). It is often assumed for symmetric uncertainties.
Oxidation: The chemical transformation of a substance by combining it with oxygen.
Population: The totality of items under consideration. In the case of a random variable, the probability distribution is taken to define the population of that variable.
Probability Density Function: (PDF) A function that describes the range and relative likelihood of possible values. The PDF describes uncertainty in the estimate of a quantity that is a fixed constant whose value is not exactly known.
Removals: The removal of greenhouse gases or their precursors from the atmosphere by a sink.
Standard Deviation: The positive square root of the variance, and a measure of the dispersion or spread of the data around the mean.
Uncertainty: A state of incomplete knowledge that can result from a lack of information or from disagreement about what is known or even knowable. It may have many sources, from imprecision in the data to ambiguously defined concepts or terminology, incomplete understanding of critical processes, or uncertain projections of human behaviour.
Sink: Any process, activity or mechanism that removes a greenhouse gas, an aerosol, or a precursor of a greenhouse gas from the atmosphere (UNFCCC Article 1.8). In the final stages of reporting a sink is written with a negative sign.
Validation: The establishment of a sound approach and foundation. For an emission inventory, validation checks that the inventory has been compiled correctly in line with the reporting instructions and guidelines.
Verification: The activities and procedures that can be followed during the planning and development of an inventory, or after its completion, to establish its reliability for its intended applications.
Several definitions above were copied from the IPCC’s 2006 Glossary of Terms

See the Monte Carlo Methods primer in the appendix↩︎

## Glossary of Terms - **Activity Data:** Data on the magnitude of a human activity that results in emissions or removals during a given period of time. - **Anaerobic:** Conditions in which oxygen is not readily available. These conditions matter for the production of methane, because organic material that decomposes without oxygen, as in a landfill or a flooded rice field, is likely to form methane. - **Andosol:** A soil developed in volcanic ash. Andosols generally drain well and are prone to fertility problems. - **Bootstrap Technique:** A computationally intensive statistical method that repeatedly resamples a set of data to assess the variability of parameter estimates. - **Back-casting:** The opposite of forecasting, in that past conditions are predicted from current conditions. - **Bias:** A systematic error of the observation method, whose magnitude in most cases is unknown. It can arise from measuring equipment that is improperly calibrated, from selecting items from the wrong population, or from favouring certain elements of a population. - **Carbon Dioxide Equivalent:** (CO~2~e) A measure used to compare different greenhouse gases by their contribution to radiative forcing. The UNFCCC currently uses global warming potentials (GWPs) as the factors for calculating carbon dioxide equivalent. - **Coefficient of Variation:** The ratio of the population standard deviation, $\sigma_x$, to the mean, $\mu_x$, where $v_x = \sigma_x / \mu_x$. It is often used to express the standard deviation as a percentage of the mean. - **Confidence Interval:** The range that encloses the true value of an unknown fixed quantity with a specified confidence. A 95 per cent confidence interval is typically assumed, and the ART-TREES Standard requires 90 per cent. - **Decision Tree:** A flow chart describing the ordered steps that must be followed to develop an inventory, or a component of one, in line with the principles of good practice. - **Emission Factor:** A coefficient that quantifies the emissions or removals of a gas per unit of activity. Emission factors are often based on a sample of measurements, averaged to give a representative rate of emission for a given activity level under a given set of operating conditions. - **Global Warming Potentials:** (GWP) The ratio of the radiative forcing of one kilogram of a greenhouse gas emitted to the atmosphere to that of one kilogram of CO2 over a period of time, such as 100 years. - **Ground Truth:** Data obtained by measurement on the ground, usually to validate remote sensing data such as satellite imagery. - **Monte Carlo Method:** [^glossary-terms-1] The statistical method recommended for analysing the uncertainty of the inventory. It performs the inventory calculation many times by computer, each time with the uncertain emission factors or model parameters and activity data drawn at random from the distributions of uncertainty specified by the user. - **Normal Distribution:** A probability distribution, also called the Gaussian distribution, defined by two parameters, the mean ($\mu$) and the standard deviation ($\sigma$). It is often assumed for symmetric uncertainties. - **Oxidation:** The chemical transformation of a substance by combining it with oxygen. - **Population:** The totality of items under consideration. In the case of a random variable, the probability distribution is taken to define the population of that variable. - **Probability Density Function:** (PDF) A function that describes the range and relative likelihood of possible values. The PDF describes uncertainty in the estimate of a quantity that is a fixed constant whose value is not exactly known. - **Removals:** The removal of greenhouse gases or their precursors from the atmosphere by a sink. - **Standard Deviation:** The positive square root of the variance, and a measure of the dispersion or spread of the data around the mean. - **Uncertainty:** A state of incomplete knowledge that can result from a lack of information or from disagreement about what is known or even knowable. It may have many sources, from imprecision in the data to ambiguously defined concepts or terminology, incomplete understanding of critical processes, or uncertain projections of human behaviour. - **Sink:** Any process, activity or mechanism that removes a greenhouse gas, an aerosol, or a precursor of a greenhouse gas from the atmosphere (UNFCCC Article 1.8). In the final stages of reporting a sink is written with a negative sign. - **Validation:** The establishment of a sound approach and foundation. For an emission inventory, validation checks that the inventory has been compiled correctly in line with the reporting instructions and guidelines. - **Verification:** The activities and procedures that can be followed during the planning and development of an inventory, or after its completion, to establish its reliability for its intended applications. - Several definitions above were copied from the [IPCC's 2006 Glossary of Terms](https://www.ipcc-nggip.iges.or.jp/public/2006gl/pdf/0_Overview/V0_2_Glossary.pdf) [^glossary-terms-1]: See the Monte Carlo Methods primer in the appendix