Greenhouse gases are defined as gas compounds such as carbon dioxide (CO2), methane (CH4), and nitrogen oxide (N2O) that absorb infrared radiation and trap heat within Earth’s atmosphere, thus creating changes in climate and weather patterns. The Greenhouse Gas Protocol was established by the World Resources Institute (WRI) and World Business Council for Sustainable Development (WBCSD) as a means of providing global standardized frameworks to measure and manage GHG emissions from private and public sector operations, value chains, and mitigation actions. Under this protocol, three “scopes” were defined to categorize the different types of GHG emissions an entity produces. Reporting of scope 1 and 2 emissions is mandatory for many organizations across the globe under the GHG Protocol. These emissions are often able to be measured and reported quite easily, as they are owned or controlled by the entity. Below is a brief description of what emission types are included within each scope.
- Scope 1 emissions are classified as emissions caused by an entity and its operations directly from controlled assets. This includes operations such as the burning of fossil fuels in a boiler to provide space heating or energy to industrial processes, the combustion of gasoline for an organization’s fleet of vehicles, and changes to entity controlled land use. Scope 1 emissions can be thought of as the emissions that an entity can directly manage. Reductions in Scope 1 emissions can often be achieved through increasing equipment or process efficiency, fuel switching, or using emission control devices.
- Scope 2 emissions are classified as emissions that an entity causes indirectly when the energy it purchases and consumes is produced. The most common source of Scope 2 emissions is the purchase of electricity. Electricity in the U.S. is generated using a variety of fuel resources and most of the electricity is generated at large centralized power plants. The energy source make-up of the power grid in the U.S. varies by region as power plants in different regions produce electricity from differing amounts of renewable and non-renewable energy sources. Reductions in Scope 2 emissions can often be achieved through increasing electrical equipment efficiency or by on-site electricity generation with renewable sources.
- Scope 3 emissions encompass emissions that are not produced by the entity itself or because of activities from owned/controlled assets, but that the entity is indirectly responsible for up and down the value chain. An example of Scope 3 emissions would be emissions resulting from business travel which is not accomplished by vehicles owned by the entity, such as using an airline. Scope 3 emissions often account for the majority of an entity’s carbon footprint, yet most of these emissions are beyond an entity’s control and are quite complicated to measure. It is due to this lack of control and complications in the product value chain that makes Scope 3 emissions tough to measure and control. Additionally, Scope 3 emissions are typically the Scope 1 or 2 emissions of another entity. Therefore, Scope 3 emissions are often not required for carbon accounting and climate action goals.