Greenhouse Gas (GHG) accounting is the process of measuring and reporting the emissions generated by a business across its operations, helping organisations meet regulatory requirements, support sustainability goals and identify opportunities to reduce their environmental impact.
It involves collecting data on activities such as fuel consumption, electricity use, business travel and supply chain operations, then converting those emissions into a standardised metric known as carbon dioxide equivalent (CO₂e).
This provides a consistent way to track emissions over time, compare performance and communicate climate-related information to investors, customers, regulators and other stakeholders.
What is GHG accounting?
GHG accounting is the process of measuring, calculating and reporting a business's greenhouse gas emissions. It accounts for gases such as carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O), converting them into a common unit called carbon dioxide equivalent (CO₂e).
This allows organisations to quantify their environmental footprint, track emissions over time and report them consistently.
Why does GHG accounting matter for businesses?
GHG accounting matters because it helps businesses understand their emissions, prioritise reduction efforts, meet stakeholder expectations and prepare for evolving reporting requirements. It shows where the largest emissions sit and which changes will have the most impact.
- Investor confidence: Auditable emissions data gives investors greater confidence in a business's climate-related claims.
- Customer trust: Transparent reporting helps build credibility with customers and other stakeholders.
- Regulatory preparedness: Maintaining an emissions inventory makes it easier to comply with evolving disclosure requirements, including frameworks such as IFRS S2.
- Greenwashing protection: Reliable emissions data helps businesses support public climate claims and reduce reputational and legal risk.
- Identifying reduction areas: Measuring emissions often reveals inefficiencies that can lead to both cost savings and lower emissions.
The scopes of greenhouse gas emissions
The GHG Protocol groups emissions into three scopes based on where they occur and the degree of control a business has over them.
Scope 1 emissions
These are direct emissions from sources a business owns or controls, such as company vehicles, diesel generators and fuel combustion in facilities.
Scope 2 emissions
These are indirect emissions from purchased electricity, heating and cooling. Companies report Scope 2 emissions using:
- Location-based method: Uses the average emission factor of the local electricity grid.
- Market-based method: Uses contractual instruments such as renewable energy certificates (RECs), Guarantees of Origin (GOs) and power purchase agreements (PPAs).
Scope 3 emissions
These are all other indirect emissions across a business's value chain. The GHG Protocol divides them into 15 categories.
- Upstream (1-8): Purchased goods and services, capital goods, fuel and energy-related activities, transportation and distribution, waste, business travel, employee commuting and leased assets.
- Downstream (9-15): Transportation and distribution, processing of sold products, use of sold products, end-of-life treatment of sold products, leased assets, franchises and investments.
For many businesses, Scope 3 is the largest source of emissions and the most difficult to measure because much of the data comes from external parties.
How the carbon reporting process works
Carbon reporting works by defining reporting boundaries, collecting emissions data, calculating emissions, verifying results and disclosing the findings.
- Define organisational boundaries: Determine which entities and operations are included using either an equity share or control approach.
- Set operational boundaries: Identify which emissions scopes will be measured. Most organisations begin with Scope 1 and Scope 2, then expand to Scope 3.
- Collect activity data: Gather fuel records, utility bills, procurement data, travel records and other relevant operational data.
- Apply emission factors: Convert activity data into emissions using appropriate emission factors. Where possible, use primary or supplier-specific data. For Scope 2 emissions, apply both location-based and market-based methods.
- Calculate total emissions: Aggregate emissions across all sources and scopes to determine the organisation's total carbon footprint.
- Verify the data: Review calculations, methodologies and supporting evidence. Independent verification can improve credibility and stakeholder confidence.
- Report and disclose: Publish emissions data through sustainability reports, CDP submissions, regulatory filings or other reporting channels.
What is changing in GHG accounting standards
GHG accounting standards are becoming more rigorous and increasingly aligned with financial reporting requirements. Key developments include:
Closer alignment between the GHG Protocol and ISO
The GHG Protocol and ISO are working to improve consistency across GHG standards and reduce overlapping requirements. This is expected to streamline assurance processes and support a more unified approach to emissions measurement and reporting.
Tighter rules for Scope 2 and Scope 3
The GHG Protocol is updating its Scope 2 and Scope 3 standards, with a greater focus on renewable electricity claims and value-chain emissions. Proposed changes aim to improve transparency and clarify the distinction between reported emissions and emissions reductions.
Stronger links to wider reporting frameworks
Frameworks such as IFRS S2 and PCAF are strengthening expectations around financed and value-chain emissions reporting. As a result, businesses are being pushed to use more robust calculation methods, higher-quality data and more consistent reporting practices.
Methods used in GHG accounting
Two primary methods are used to calculate emissions, and they are not mutually exclusive.
Spend-based method
This method multiplies the value of purchases by an average emission factor for the relevant spending category. It is easier to apply and is often used when detailed operational data is unavailable, though it is generally less accurate.
Activity-based method
This method uses actual physical data, such as litres of fuel consumed or kilowatt-hours of electricity used, and applies relevant emission factors. It requires more data collection but provides more accurate results.
Activity-based calculations are preferred where primary data is available, while spend-based estimates are typically used for less material categories or data gaps. Data quality generally follows a hierarchy: primary activity data, supplier-specific factors, regional or sector averages, and spend-based estimates.
Note: Use emission factors from reputable sources such as national inventories, the International Energy Agency (IEA), the IPCC, GHG Protocol tools or industry-recognised databases, and choose factors that match the relevant geography, fuel type and technology.
GHG accounting in India
GHG accounting in India is primarily guided by the GHG Protocol and supported by initiatives such as the India GHG Program, which helps businesses measure, report and manage their greenhouse gas emissions. Launched in 2012 by WRI India, CII and TERI, the programme provides tools, guidance and technical support for developing emissions inventories and identifying reduction opportunities.
For Indian businesses, GHG accounting supports regulatory preparedness, sustainability reporting and emissions reduction planning. It also helps build credibility with investors, customers and international partners by demonstrating a structured approach to managing climate-related risks and opportunities.
Conclusion
GHG accounting helps businesses measure emissions, identify reduction opportunities, meet reporting requirements and set credible sustainability targets backed by data. As climate disclosures become more rigorous, maintaining accurate financial and operational records is essential for building a reliable emissions inventory.
Solutions such as TallyPrime support the record-keeping discipline needed for effective reporting, compliance and informed decision-making.
