Greenhouse gas (GHG) inventories help organisations understand and manage emissions associated with their activities. When prepared consistently, they make it possible to identify major sources of emissions, track performance over time and determine where reduction efforts may have the greatest effect.
A corporate inventory should be distinguished from a product carbon footprint study. A corporate inventory accounts for emissions within defined organisational and operational boundaries. A product assessment considers emissions associated with the life-cycle stages of a product, according to the study's goal and system boundaries. These approaches answer different questions and can complement one another.
The GHG Protocol provides standards and guidance for different purposes. The Corporate Standard supports corporate inventories; the Corporate Value Chain (Scope 3) Standard addresses value-chain emissions; and the Product Life Cycle Standard was developed to quantify and report GHG emissions across a product's life cycle.
Depending on the applicable rules and system boundaries, a product assessment may cover raw-material extraction and processing, manufacturing, transport, distribution, use and end of life. The analysis helps identify the stages that contribute most to the result and assess opportunities to improve products, processes and supply chains.
Results can also support responses to customer and stakeholder requests. To be useful, an assessment should document its boundaries, data, assumptions and calculation methods. Results prepared using incompatible approaches should not be compared as if they were equivalent.