Activity Data

From Open Risk Manual


Activity Data are quantitative measures of a level of activity that results in GHG Emissions. It is a measure that models what is taking place during a given period of time (e.g., volume of gas used, kilometers driven, tonnes of solid waste sent to landfill, etc.)


  • Data should be from reliable and robust sources
  • Data should be time- and geographically-specific to the GHG Inventory Boundary, and technology-specific to the activity being measured

Data Sourcing

Data Sourcing (Collection) is an integral part of developing and updating a GHG Inventory. This includes gathering existing data, generating new data, and adapting data for inventory use. [1]

Data can be gathered from a variety of sources, including government departments and statistics agencies, a country’s national GHG inventory report, universities and research institutes, scientific and technical articles in environmental books, journals and reports, and sector experts/stakeholder organizations. In general, it is preferable to use local and national data over international data, and data from publicly-available, peer-reviewed and reputable sources, often available through government publications.

It may be necessary to generate new data if the required activity data does not exist or cannot be estimated from existing sources. This could involve physical measurement, sampling activities, or surveys. Surveys may be the best option for most emission sources, given the tailored data needs of entity-wide GHG inventories, although they can be relatively expensive and time-consuming without proper guidance. Land use categories may also have removal factors i.e., the amount of CO2 removed from the atmosphere per unit of activity data (often expressed in hectares).

Data Scaling

Where the best available activity data do not align with the geographical boundary of the entity or the time period of the assessment, the data can be adapted to meet the inventory boundary by adjusting for changes in activity using a scaling factor. The scaling factor represents the ratio between the available data and the required inventory data, and should reflect a high degree of correlation to variations in the data. Scaled data can be useful and relevant where data for the inventory year, or entity-specific data, are unavailable or incomplete. (See also Data Scaling, Data Normalization)

Documentation Requirements

The following information should be requested and recorded when sourcing data:

  • Definition and description of the data set: time series, sector breakdown, units, assumptions, uncertainties and known gaps
  • Frequency and timescales for data collection and publication
  • Contact name and organization(s) / entities of data providers


Activity data is multiplied by an GHG Emission Factor to derive the GHG emissions associated with a process or an operation. [2]


  • kilowatt-­hours of electricity used
  • quantity of fuel used
  • output of a process
  • hours equipment is operated
  • distance traveled, and
  • floor area of a building

Issues and Challenges


  1. Global Protocol for Community-Scale Greenhouse Gas Inventories, An Accounting and Reporting Standard for Cities, Version 1.1, 2021. WRI, C40, IOCLEI
  2. The Greenhouse Gas Protocol, Policy and Action Standard