GHG Notation Keys

Definition

GHG Notation Keys are specific Data Completeness indicators that are recommended by IPCC in the preparation of GHG Accounting reports.

General IPCC Recommendation

In all reports used by entities to summarise their inventory data, it is good practice to fill in information for all entries. If actual emission and removal quantities have not been estimated or can not otherwise be reported in the tables, the inventory compiler should use qualitative notation keys and provide supporting documentation.

Notation keys are appropriate if emission estimates or removal are incomplete, or representative of only a part of the total activity, or require clarification when specific greenhouse gas emissions were not reported, for any particular source or sink category. In this way it is good practice to report on the completeness of each individual emission estimate.

Completeness means that inventory estimates have been prepared for all categories and gases. A country may consider that a disproportionate amount of effort would be required to collect data for a category or a gas from a specific category that would be insignificant in terms of the overall level and trend in national emissions. In these circumstances a country should list all categories and gases from categories excluded on these grounds, together with a justification for exclusion in terms of the likely level of emissions or removals and identify the category as 'Not Estimated' using the notation key 'NE' in the reporting tables.

Description

To accommodate limitations in data availability and differences in emission sources between local governments, the following notation keys may be used in the GHG emissions inventories in absence of emissions data or if an emission source category does not occur in the city. Where notation keys are used, an accompanying explanation shall be provided.

• NO (not occurring): An activity or process does not occur or exist within the city. This notation key may also be used for insignificant sources (see Box 1 for definition). For example, NO may be used for the Aviation sub-sector if there are no aviation activities that both start and end within the city boundary. This reason should be stated in the inventory as an explanation for the use of the notation key. Another example of the use of NO, is a city that determines that emissions from waterborne transportation within the city boundary are insignificant. The notation key NO can be used, as long as it is explained why it is considered insignificant.
• IE (included elsewhere): GHG emissions for this activity are estimated and presented in another category in the same inventory, stating what that category is. This notation key may be used where it is difficult to disaggregate data into multiple sub-sectors. This notation key can also be used when waste is used for generating energy. In these circumstances IE can be used in the relevant waste sub-sector.
• C (confidential): GHG emissions which could lead to the disclosure of confidential information, and as such are not reported publicly. For instance, certain military operations or industrial facilities may not permit public data disclosure where this impacts security.
• NE (not estimated): GHG emissions occur but have not been estimated or reported, with a justification why. NE cannot be used for emission sources that are required by the mandatory reporting level. Use of NE should also be minimised for non-mandatory emission sources by exploring methodologies and data sources to make best estimates.
• NA (not applicable): The activity or category exists but relevant emissions and removals are considered never to occur. Such cells are normally shaded in the reporting tables.

Note

The 2006 IPCC Guidelines include the notation key “NA—Not Applicable” for activities that occur but do not result in specific GHG emissions. For the purposes of the GPC, the notation key “NA” does not apply because the use of notation keys in the GPC is focused on GHG emission source categories, rather than specific gases, and does not require the same level of disaggregation as national inventories.