As I mentioned in my previous blog, the first thing I would ever suggest that someone do when they're wanting to start looking at reducing their emissions is to calculate them. The first step in calculating your emissions is to understand how they are categorised. The Greenhouse Gas Protocol (GHG Protocol) is a leading international standard for measuring and reporting greenhouse gas emissions. The GHG Protocol defines three scopes of emissions

Scope 1: Direct emissions from sources owned or controlled by the organisation. This includes emissions from burning fuel for heating or transportation, as well as emissions from fugitive emissions (e.g., methane leaks from natural gas pipelines).

Scope 2: Indirect emissions from the generation of purchased electricity, steam, heat, and cooling. This includes emissions from power plants that generate electricity that is purchased by the organisation.

Scope 3: All other indirect emissions that occur in the value chain of the organisation. This includes emissions from transportation of goods, waste disposal, and employee commuting.

The above image from a  GHG protocol report summarises the different scopes. Scope 1 and 2 emissions are considered to be more "direct" emissions, as they are more easily attributable to the organisation. Scope 3 emissions are considered to be more "indirect" emissions, as they are more difficult to attribute to the organisation. However, Scope 3 emissions can often be the largest source of emissions for an organisation.

As it stands most mandatory emissions reporting only requires a subset of scope 3 emissions. The NHS Carbon Reduction Plans only require data on 5 aspects of scope 3; upstream transportation and distribution, waste generated in operations, business travel, employee commuting and downstream transportation and distribution.