How to avoid double-counting in carbon accounting: A practical guide

Carbon accounting is a critical part of any sustainability strategy, but it’s easy to make mistakes — especially when it comes to double-counting emissions. Whether you’re measuring your own carbon footprint or tracking emissions across a supply chain, avoiding double-counting ensures accurate reporting and credible climate commitments. This guide breaks down what double-counting is, why it matters, and how to prevent it.

What is double-counting in carbon accounting?

Double-counting happens when the same emissions are recorded more than once in a carbon inventory. This can occur within a single organization (e.g., when two departments claim the same emissions) or across multiple entities (e.g., when both a supplier and a buyer count the same emissions in their Scope 3 calculations). It skews data, inflates footprints, and undermines transparency in emissions reporting.

Under the Greenhouse Gas (GHG) Protocol, emissions are categorized into three scopes:

• Scope 1: Direct emissions from owned or controlled sources (e.g., company-owned vehicles).
• Scope 2: Indirect emissions from purchased electricity, heat, or steam.
• Scope 3: All other indirect emissions, including supply chain and product lifecycle emissions.

The biggest risk of double-counting arises in Scope 3, where emissions can be reported by multiple organizations within the same value chain.

Why double-counting is a problem

Double-counting distorts the accuracy of carbon data, leading to several issues:

• Inconsistent carbon footprints: If multiple entities claim the same emissions, total reported emissions can exceed actual global emissions.
• Misleading sustainability claims: Companies may overstate their impact reductions, leading to greenwashing concerns.
• Regulatory and reporting challenges: Frameworks like the GHG Protocol, SBTi, and CSRD require clear and verifiable emissions data. Double-counting can lead to non-compliance or reputational risks.
• Poor decision-making: If data isn’t accurate, companies may invest in the wrong decarbonization strategies.

Where double-counting commonly occurs

Scope 2 emissions and market-based accounting

Double-counting in Scope 2 emissions often happens when organizations use a mix of location-based and market-based reporting. The location-based method calculates emissions based on the grid’s average emission factor, while the market-based method accounts for purchased renewable energy certificates (RECs) or power purchase agreements (PPAs). If both the generator and the buyer claim the same renewable energy benefits, emissions savings can be overstated.

Scope 3 emissions in the supply chain

Scope 3 emissions are the biggest source of double-counting. If a manufacturer and a retailer both include the same emissions from a product’s production and transportation, total reported emissions may be inflated. The same issue arises in financial reporting when multiple investors claim emissions from the same asset.

Carbon credits and offsetting

A common double-counting pitfall occurs when both the organization purchasing a carbon credit and the host country where the project takes place claim the same reduction. This can happen in voluntary carbon markets if there isn’t a clear distinction between project ownership and credit retirement.

Best practices to prevent double-counting

1. Establish clear organizational boundaries

Following the GHG Protocol’s control approaches (equity share or operational control) ensures each entity reports emissions consistently. Define whether your company reports based on financial ownership or operational control to prevent overlaps.

2. Coordinate Scope 3 reporting with suppliers and customers

Since Scope 3 emissions inherently involve multiple stakeholders, it’s essential to align methodologies. Engaging with suppliers, setting standardized reporting frameworks, and using shared emissions factors can help avoid duplication. Platforms like Avarni provide automated Scope 3 data mapping to ensure supply chain emissions are correctly allocated.

3. Use a consistent reporting approach for Scope 2

When reporting Scope 2 emissions, choose a consistent approach — either market-based or location-based—and be transparent about how renewable energy purchases are accounted for. If using RECs or PPAs, ensure that emission reductions are not counted both by the generator and the buyer.

4. Ensure transparency in carbon credit claims

To prevent double-counting in carbon offsets, organizations should only claim reductions from credits that have been retired in their name. Verifying project ownership and using certified registries like Verra or Gold Standard helps ensure credibility.

5. Leverage technology to track emissions accurately

Manually tracking emissions across an organization and supply chain increases the risk of errors. Avarni’s AI-driven platform automates emissions calculations, ensuring data integrity and reducing duplication. By integrating supplier data and streamlining Scope 3 reporting, Avarni helps organizations avoid double-counting and improve overall carbon transparency.

Summary

• Double-counting happens when emissions are counted more than once, often in Scope 3 reporting or carbon credit claims.
• It leads to inaccurate data, undermining sustainability goals, regulatory compliance, and decision-making.
• Scope 2 reporting must be consistent to avoid over-claiming renewable energy benefits.
• Scope 3 coordination with suppliers and customers is key to accurate emissions tracking.
• Carbon credits should be carefully accounted for to prevent multiple claims on the same reductions.
• Using technology like Avarni ensures accurate emissions tracking, eliminating duplication and improving sustainability reporting.