What are the differences between Scope 1, 2 and 3 Greenhouse Gas emissions?

Written by Steven Boles

Greenhouse gas (GHG) emissions are one of the sustainability performance indicators that are most requested by stakeholders. A group called The Greenhouse Gas Protocol has been very influential in defining how organizations should manage and report their GHG, including the establishment of three categories of emissions (Scope 1, Scope 2, Scope 3). The separation of GHG emissions into scopes is designed to avoid ‘double-counting’ of emissions, and is also intended to help organizations categorize GHG into those that they control (e.g. Scope 1) versus those that they can influence (e.g. Scope 3).

Scope 1 are also referred to as Direct GHG, and are defined as ‘emissions from sources that are owned or controlled by the organization’, such as:

  • Stationary Combustion: from the combustion of fossil fuels (e.g. natural gas, fuel oil, propane, etc.) for comfort heating or other industrial applications
  • Mobile Combustion: from the combustion of fossil fuels (e.g. gasoline, diesel) used in the operation of vehicles or other forms of mobile transportation
  • Process Emissions: emissions released during the manufacturing process in specific industry sectors (e.g. cement, iron and steel, ammonia)
  • Fugitive Emissions: unintentional release of GHG from sources including refrigerant systems and natural gas distribution

For the majority of organizations the stationary and mobile combustion sources of Scope 1 GHG will be the most relevant.

Scope 2 are also referred to as Energy Indirect GHG, and are defined as ‘emissions from the consumption of purchased electricity, steam, or other sources of energy (e.g. chilled water) generated upstream from the organization’.

Scope 3 are also referred to as Other Indirect GHG, and are defined as ‘emissions that are a consequence of the operations of an organization, but are not directly owned or controlled by the organization’. Scope 3 includes a number of different sources of GHG including employee commuting, business travel, third-party distribution and logistics, production of purchased goods, emissions from the use of sold products, and several more. Based on data from many companies that have conducted comprehensive assessments of their Scope 3 emissions, it is evident that Scope 3 GHG are by far the largest component of most organizations’ carbon footprint.