How can Impact Units support value chain decarbonization?

Decarbonizing complex value chains is one of the greatest challenges companies face on their path to net zero. Multiple actors — from suppliers to manufacturers to retailers — are involved in reducing and removing emissions. Sharing the costs and benefits of these efforts across such a diverse network is rarely straightforward.

SustainCERT has developed Impact Units to make this process easier. Impact Units enable companies to share the cost of interventions across the value chain and be recognized for the impact generated. They can be integrated into company reports, transferred, and even co-claimed between value chain partners, incentivizing joint action on value chain decarbonization. By fall of 2025, we have issued more than 700.000 Impact Units.

What exactly are Impact Units and how do they work? Let's answer some common questions.

What are Impact Units?

Impact units (IUs) are a mechanism developed by SustainCERT to help organizations translate the mitigation outcomes of their value chain interventions into corporate Scope 3 reporting.

Each Impact Unit represents one ton of carbon reduced or removed by an intervention project. Every IU is tied to a specific amount of product or raw material and contains verified, location- and activity-specific emission factor data that can be used directly for Scope 3 inventory and sustainability reporting.

This enables companies to be recognized for the actions they take to decarbonize their value chain.

Why Impact Units?

For most companies, Scope 3 emissions make up as much as 90% of total emissions, making their reduction essential to any credible net zero strategy. Because value chains involve numerous independent actions, there is a need for processes that allow companies to co-invest in interventions and share the results fairly among partners.

Impact Units enable companies to transfer or co-claim emission reductions or removals, allowing all participant partners to report their share of impact in their inventories.

Beyond reporting, Impact Units support transparent collaboration and cost-sharing, addressing key Scope 3 accounting challenges such as free riding, double counting and over-claiming. This encourages collective action and helps scale decarbonization efforts across entire value chains.

How do Impact Units work?

When a company implements an intervention in its value chain, it can pursue validation and/or verification with SustainCERT. Once the process is successfully completed, Impact Units are issued to the intervention owner through SustainCERT’s Impact Management Platform.

The Platform provides an end-to-end solution — from verifying interventions, to enabling co-claiming, and supplying the data needed for Scope 3 inventory reporting. It helps companies manage, transfer, claim, and report verified Scope 3 GHG outcomes, ensuring transparency and fostering collaboration across the value chain.

Validation and verification are conducted according to SustainCERT’s Verification Requirements for Value Chain Interventions, developed in line with global best practices and informed by advanced life-cycle analysis. A public registry lists all verified interventions with issued Impact Units, further enhancing transparency.

What kind of interventions can be issued Impact Units?

An intervention is any action that introduces a change to a Scope 3 activity to reduce or remove emissions — for example, introducing a new technology, adopting a sustainable practice or supply change.

Depending on the sector, interventions might include regenerative agriculture practices, low-emission technologies, or improvements in supply chain efficiency.

How do Impact Units support climate reporting and claims?

Impact Units contain verified mitigation data, and verified, location-specific emission factor data, that can be extracted and used for sustainability reporting and Scope 3 inventory reporting.

This enables:

• Greater accuracy in emissions reporting
• Collaboration across partners with varying levels of reporting maturity
• Credible, year-over-year emissions tracking using standardized, location-specific data
• Transparent demonstration of progress toward Scope 3 targets

How is double counting avoided when co-claiming Impact Units?

Impact Units are designed to enable credible co-claiming of mitigation outcomes, even in complex or partially traceable supply chains. To prevent double counting the following safeguards apply:

• Claims are limited to the quantity of goods sourced by the claimant
• Impact Units are issued across five distinct stages of the value chain, called Impact Layers. Each layer reflects a different position in the value chain (e.g., raw material production or retail), allowing multiple actors to co-claim verified outcomes, without risk of double counting.
• Self-attestation is required. Claiming companies must submit a Deed of self-attestation confirming both their position in the value chain and their connection to the intervention’s Supply Shed.

Impact Layers simplify the highly complex and often opaque nature of global value chains, serving as a standardized proxy that enables credible, scalable claims without requiring full traceability.

Companies within the same Impact Layer (e.g., raw material production) cannot claim the same Impact Units, while companies in different impact layers (e.g., raw material production and retail) can co-claim the same impact as they operate in distinct stages of the value chain.

Can Impact Unit data be incorporated into a Scope 3 inventory?

Yes. Each IU includes post-intervention, emission factor data that is location and activity specific. This data can be used in a Scope 3 inventory through a method called substitution, where a generic emission factor in a Scope 3 inventory is replaced with a more accurate emission, post-intervention one.

This approach — described in the Value Change Initiative (VCI) Food and Agricultural guidance and aligned with the GHG Protocol — improves precision by integrating primary data into a default emission factor, provided both datasets share comparable boundaries (e.g., similar material, spatial, temporal, and technological).

The method disaggregates the reported default emission factor into its components, such as processes, operations, or activities, and replaces relevant elements with updated, intervention-specific estimates for a given year. As a result, post-intervention emissions can directly substitute their historical counterparts in the inventory.

In simple terms, substitution lets companies replace generic data with real, verified data from their supply chains. The updated emission factor is then multiplied by the relevant volume of goods sourced or purchased, producing a more accurate emissions estimate. This substitution method is functionally equivalent to the hybrid method described in the GHG Protocol’s Scope 3 Guidance, and results in an updated emission factor.

Importantly, the use of this emission factor is limited to the quantity of product or raw material involved in the intervention.

Can Impact Units be used as part of an insetting approach?

Yes. Impact Units can support corporate insetting programs, which aim to reduce emissions within a company’s own value chain.

According to the International Platform for Insetting (IPI), insetting projects are “interventions along a company’s value chain that are designed to generate GHG emissions reductions and carbon storage, and at the same time create positive impacts for communities, landscapes and ecosystems.”

Impact Units contribute to insetting by enabling companies to co-invest in value chain interventions. They support credible and collaborative decarbonization through:

• Allowing more than one company can claim the impact.
• The right to report is checked through proof of sourcing/connection to the Supply Shed.
• The impact that can be claimed by a company is capped to the volume sourced.