Greenhouse Gas: Introduction to scope 1, 2 & 3 emissions

Is there any activity that does not generate greenhouse gas (GHG) emissions?

I believe it is safe to say that all products, processes, people and organizations generate  GHGs directly or indirectly in our daily living. These are gases that trap heat in the atmosphere (thereby making our planet warmer).

These GHGs include:

  1. Carbon dioxide (CO2): This GHG is mostly generated and released into the atmosphere when you and I burn fossil fuels (coal, natural gas, and oil).
  2. Nitrous oxide (N2O): This is emitted largely during agricultural and industrial activities as well as combustion of fossil fuels just as carbon dioxide.
  3. Methane (CH4): From the production and transport of coal, natural gas, and oil, methane is generated. Other useful (I say useful because these are renewable energy goldmines) sources of methane are livestock farming and decay of organic waste in landfills.
  4. Fluorinated gases: The other three GHGs are Hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride (SF6) otherwise classified as Fluorinated gases. These are synthetic, powerful greenhouse gases that are emitted from a variety of industrial processes. These gases are typically emitted in smaller quantities than other GHGs, but because they are potent greenhouse gases, they are sometimes referred to as High Global Warming Potential gases (“High GWP gases”)
SOURCE: US Environmental Protection Agency.

Greenhouse gas (GHG) emissions are one of the key sustainability performance indicators that are most requested by stakeholders. In calculating and reducing your carbon footprint, various groups have been influential in defining how we should manage and report our GHG. One of such groups is the GHG protocol which has recorded numerous successes including the establishment of three categories of emissions (Scope 1, Scope 2, Scope 3).

Truth be told, there is a “control” and “influence” dichotomy that we need to understand as well. The whole idea of the separation of GHG emissions into scopes is designed to avoid ‘double-counting’ of emissions, and is also intended to help you categorize GHGs into those that you can control (e.g. Scope 1) versus those that you 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 your 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

It is important to state here that 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.



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