Emissions broadly refer to the release of greenhouse gases (GHGs) into the atmosphere, which contribute to climate change by trapping heat. These emissions can arise from various natural and human-driven activities, such as energy production, transportation, industrial processes, and agriculture.
In the context of companies and organisations, emissions are categorised into three distinct scopes based on their source and level of control:
Direct emissions (Scope 1)
Scope 1 GHG emissions originate from sources that are owned or controlled by the organisation. These represent the most immediate and controllable emissions for any company.
Indirect energy emissions (Scope 2)
Scope 2 emissions result from the generation of purchased or acquired electricity, steam, heat, or cooling consumed by the organisation. For instance, when a company operates electric vehicles without generating its own power, the emissions from producing the electricity used in these vehicles fall under Scope 2.
Value chain emissions (Scope 3)
Scope 3 emissions encompass all other indirect GHG emissions occurring throughout the organisation's value chain, including both upstream and downstream emissions. These emissions are typically the most comprehensive and complex to measure.
Measurement and calculation of carbon emissions
To calculate business emissions, two fundamental components are required:
- Activity Data: This is a quantitative measure of activities resulting in GHG emissions, such as litres of fuel consumed or kilograms of materials purchased.
- Emission Factors: These are conversion factors that transform activity data into GHG emissions data, measured in units such as kg CO₂ emitted per litre of fuel consumed.
Units of measurement
Emissions are typically measured in CO₂ equivalent (CO₂e), which is a standardised unit used to express the global warming potential of different greenhouse gases as a single figure, representing the equivalent amount or concentration of carbon dioxide.
