Greenhouse Gas (GHG) accounting is a crucial process for corporate companies looking to understand, manage, and reduce their environmental impact. As the world focuses on climate action, knowing how to measure your company's carbon footprint is the first step toward sustainability.
This post breaks down the core concepts of GHG accounting in an easy-to-digest way for beginners.
What is GHG Accounting?
GHG accounting is the process of measuring the amount of greenhouse gases released into the atmosphere as a result of a company's operations. Think of it as a financial audit — but instead of tracking money, you're tracking carbon dioxide and other GHGs.
The goal is to create an accurate GHG inventory — a comprehensive list of all emission sources and their quantities.
The main GHGs tracked are those specified in the Kyoto Protocol and Paris Agreement, including:
- Carbon Dioxide (CO₂)
- Methane (CH₄)
- Nitrous Oxide (N₂O)
- Fluorinated Gases (HFCs, PFCs, SF₆, NF₃)
All emissions are typically converted into a single unit called Carbon Dioxide Equivalent (CO₂e) for easy comparison and aggregation.
Core Principles of GHG Accounting
To ensure that a company's GHG inventory is credible and reliable, several core principles must be followed:
| Principle | Explanation |
|---|---|
| Relevance | The inventory must appropriately reflect the GHG emissions of the company and serve decision-making needs. |
| Completeness | All relevant emissions sources within the defined boundary must be included. |
| Consistency | Use consistent methodologies so data is comparable over time. |
| Transparency | All assumptions, methodologies, and data sources must be clearly documented. |
| Accuracy | Emissions data should be systematically correct and minimize uncertainties. |
Scopes and Boundaries: Defining Your Footprint
1. Organizational Boundaries
Determines which parts of the company are included. Companies typically choose between:
- Equity Share: Based on the share of ownership.
- Control: 100% of emissions from operations under financial or operational control.
2. Operational Boundaries: The Three Scopes
Emissions from sources owned or controlled by the company (e.g., company-owned vehicles, on-site boilers).
Emissions from purchased electricity, steam, heating, and cooling consumed by the company.
Occur in the value chain, both upstream (suppliers) and downstream (customers). These are typically the largest and most complex to track.
Tracking Corporate Emissions: Step-by-Step
Set Boundaries
Define the time period (e.g., calendar year) and choose the control approach — equity share or operational control.
Data Collection
Gather Activity Data (liters of diesel, kWh of electricity) and pair each with the appropriate Emission Factor (kg CO₂e per unit of activity).
Calculate Emissions
Multiply the Activity Data by the Emission Factor to get your total in CO₂ equivalent:
Verification and Reporting
Aggregate data and have it audited by an independent third party before disclosure in sustainability reports or platforms like CDP.
Activity Data vs Emission Factors
| Data Type | Definition | Example |
|---|---|---|
| Activity Data | Quantitative data on emission-generating activities. | Liters of diesel, kWh of electricity. |
| Emission Factors | Coefficient that translates activity to GHG quantity. | kg CO₂e per liter of diesel. |
Getting Started: If your company is new to GHG accounting, start small. Focus first on Scope 1 and Scope 2 — these are the most direct and easiest to measure. Once you have a baseline, expand into Scope 3. For detailed guidance, refer to the official GHG Protocol Corporate Standard.