Corporate GHG Emissions Tracking: A Practical Guide

Corporate greenhouse gas tracking is no longer a voluntary exercise for large companies. California's SB 253, CSRD's ESRS E1, the ISSB S2 climate standard, and the SEC's climate disclosure rule all require companies to measure, report, and in many cases verify their GHG emissions. For companies that have not previously built a structured emissions inventory, the question is not whether to start but how.

This guide covers the practical mechanics: how to set up a corporate GHG inventory, what data you need for each emissions scope, what tools support the process at scale, and what each major regulatory framework requires from your tracking system.

Scope 1, 2, and 3 — What You're Tracking and Why It Matters

The GHG Protocol Corporate Standard — the methodology used by the large majority of corporate GHG inventories globally — organises emissions into three scopes based on where in your value chain they originate:

• Scope 1: Direct emissions from sources owned or controlled by the company — combustion in boilers and furnaces, company vehicle fleets, fugitive emissions from refrigerants, process emissions from manufacturing. These are the most controllable and typically the easiest to measure.
• Scope 2: Indirect emissions from purchased electricity, steam, heat, and cooling. Measured using either a location-based method (average grid emission factor for your region) or a market-based method (emission factors from energy certificates, direct contracts, or supplier-specific rates).
• Scope 3: All other indirect emissions across your value chain — from raw material extraction, supplier manufacturing, product transportation, customer use, and end-of-life disposal. Typically 70–90%+ of a company's total footprint, but the hardest to measure and the most dependent on external data.

The distinction between scopes matters for tracking systems because the data sources, calculation methodologies, and update frequencies are completely different for each. A single platform should handle all three, but the workflows for each scope are distinct.

Setting Up Your GHG Inventory

Before collecting any data, establish three foundational parameters:

• Organisational boundary: which entities are included? The GHG Protocol offers three approaches — operational control (all entities over which you have operational control), financial control (entities consolidated in your financial accounts), and equity share (your proportionate ownership share). CSRD requires the same boundary as financial reporting for large companies.
• Operational boundary: which emission sources are included? All Scope 1 and 2 sources must be included; Scope 3 categories are included based on materiality assessment.
• Base year: the reference year against which progress is measured. Typically the first year with complete, reliable data. Base year recalculation rules (when the boundary or methodology changes) must be documented upfront.

These three decisions, once made and documented, define the scope of your inventory and therefore the data collection burden. Changing them mid-stream without a documented restatement is one of the most common audit findings in corporate GHG disclosure.

Data Sources for Each Scope

Scope 1 Data Sources

Natural gas and fuel combustion: invoices from energy suppliers or fuel purchase records, combined with published calorific values and emission factors (UK DEFRA, US EPA, IPCC).

Fugitive refrigerant emissions: maintenance logs showing refrigerant top-up quantities and the GWP of each refrigerant type.

Company vehicles: fuel purchase records or distance travelled combined with vehicle emission factors.

Scope 2 Data Sources

Electricity consumption: utility invoices or smart meter data, by facility and by month.

For market-based accounting, energy attribute certificates (Renewable Energy Certificates, Guarantees of Origin) must be matched to consumption periods.

For location-based, national or regional grid emission factors from official sources (International Energy Agency, DEFRA, EPA eGRID) are applied.

Scope 3 Data Sources

Category 1 (purchased goods and services): supplier-reported emissions or spend-based estimation using EEIO factors.

Category 4 (upstream transportation and distribution): freight weight, distance, and modal emission factors.

Category 6 (business travel): airline booking records plus published seat-mile emission factors.

Category 11 (use of sold products): sales volume combined with product emission factor (from LCA or engineering calculations).

See our detailed Scope 3 categories guide for data source recommendations by category.

Tools for Corporate GHG Tracking

The right tooling depends on the scale and complexity of your inventory. Three tiers are typical:

• Spreadsheet-based inventory: appropriate for small companies with Scope 1+2 only and fewer than five facilities. Quickly becomes unmanageable at scale — audit trail is weak, error rates increase with manual data entry, and version control is manual.
• Point tool (single-scope or single-function): tools focused on one aspect of GHG tracking, such as travel emissions calculators or Scope 2 market-based accounting modules. Useful as supplements but create fragmentation across the full inventory.
• Integrated GHG/ESG platform: handles all three scopes in a single system, with automated data ingestion from source systems, built-in emission factor libraries (updated annually), calculation audit trails, and disclosure-ready output. The right choice for any company facing regulatory reporting requirements.

When evaluating platforms, the critical questions for GHG tracking specifically are: does it maintain an auditable calculation log (not just the output)? Does it update emission factor libraries on a documented schedule? Does it support both location-based and market-based Scope 2 simultaneously? Can it generate output formatted for ESRS E1, ISSB S2, and GHG Protocol Corporate Standard disclosure?

Meeting Regulatory Requirements

The major regulatory frameworks have materially different requirements from your GHG tracking system:

• CSRD / ESRS E1: requires disclosure of Scope 1, 2, and 3 emissions with a documented methodology, prior-year comparatives, intensity metrics, and alignment with climate transition plans. Third-party limited assurance is mandatory from year one.
• California SB 253: Scope 1 and 2 data required annually; Scope 3 data required biennially. Third-party verification required for Scope 1+2 from 2026 reporting year (covering FY 2025). Verification standard must meet CEPACB-approved criteria.
• ISSB S2: Scope 1, 2, and material Scope 3 emissions; industry-specific metrics from SASB standards; scenario analysis (including 1.5°C scenario); transition plan disclosure.
• SEC Climate Rule: as currently stayed, would require Scope 1+2 from large accelerated filers, with Scope 3 if material or included in targets. Verification required in phases. Monitor enforcement status before assuming applicability.

See our GHG Protocol guide for a detailed walkthrough of the foundational methodology that underpins all of these regulatory frameworks.

Common Pitfalls in Corporate Emissions Tracking

• Double-counting Scope 2 emissions — using both location-based and market-based totals in the same disclosure boundary rather than choosing one primary method and reporting the other separately
• Outdated emission factors — using 2019 grid emission factors in a 2024 inventory introduces systematic error, particularly for grids that have substantially decarbonised
• Incomplete Scope 3 category screening — skipping the materiality assessment step and only reporting the easiest categories (business travel, waste) while omitting the largest (purchased goods, use of sold products)
• Base year locked without a recalculation policy — acquisitions, divestitures, or methodology changes require base year restatement; without a documented policy, auditors flag this as an inconsistency
• Treating Scope 3 as optional — for companies subject to CSRD, ISSB, or SB 253 with material Scope 3 categories, omission creates disclosure liability even where the framework technically allows omission with justification

A well-structured GHG inventory is the foundation of every credible climate disclosure — and the prerequisite for third-party assurance. Building it correctly from the start, with the right data sources and a system that maintains an auditable trail, costs far less than rebuilding after a failed assurance engagement.