Reporting Carbon Emissions from Waste: Avoiding the Pitfalls
Author | Tim Maiden
Reading Time - 3 mins
What the DESNZ Conversion Factors Are (and Aren't) For
DESNZ publishes greenhouse gas conversion factors with a specific, narrow mandate: to help organisations report their greenhouse gas emissions for a given year. In the context of waste, these factors exist specifically to calculate Scope 3, Category 5: Waste Generated in Operations.
Where things go wrong is when organisations assume these factors represent the complete carbon story of their waste, including the downstream benefits of recycling. They do not and expecting them to is often where the data gets skewed.
The Key Limitation: Where the Line is Drawn
The core limitation to keep in mind is that DESNZ waste factors are designed for corporate carbon footprinting, not for strategic waste and resource management decisions. Why? Because the methodology draws an intentional line part-way through your waste's lifecycle.
Here is how that boundary plays out in practice:
- Landfill: If your waste goes to landfill, the emissions from landfill are treated as yours because you are the final user of the material in that lifecycle.
- Recycling and Reuse: If your waste is recycled or reused in some way, the vast majority of what happens next is allocated to the next user of that material, not to you.
Consequently, the emissions associated with recycling, composting, waste-to-energy, and anaerobic digestion processes are all assigned to the next user of those outputs. They disappear from your own carbon footprint.
In short, the DESNZ factors for recycling pretty much only account for the transportation of the waste to the recycling or energy recovery facility.
This boundary choice is entirely intentional. It is a mechanism that ensures consistent, standardised corporate reporting across the board. However, while it makes the numbers incredibly useful for a compliance spreadsheet, it also means they are fundamentally incomplete if you are trying to use them to make actual operational decisions about managing waste.
Data for waste decision-making
For operational decisions about waste and resource management, ‘whole-life’ data is needed.
These data have different boundaries to the DESNZ factors and are increasingly being used by waste management companies to help their customers understand the carbon benefits of recycling and re-use.
These data are not meant for use in organisational carbon footprint reporting but it’s very tempting for customers to receive data on the carbon reductions they have achieved by recycling and treating this as a reduction in the carbon footprint of their organisation.
Whole-life savings from re-use and recycling are real benefits, but they are not reductions inside your organisational footprint.
The Strategic Takeaway
Use DESNZ waste factors or equivalent for reporting an organisation’s footprint.
Use whole-life factors for decision making about waste options.
Do not mix them.
Most importantly: If you calculate whole-life ‘savings’, do not subtract them from your organisational footprint.
If you get the boundaries wrong, you risk overstating reductions, confusing your audience, and undermining trust in your carbon reporting.
Good carbon accounting is not just about having numbers. It is about using the right numbers for the right purpose, and being clear about what they do and do not mean.
