Greenhouse Gas Protocol (GHG Protocol)

What is the GHG Protocol?

The Greenhouse Gas (GHG) Protocol is the most widely used international standard for accounting and reporting greenhouse gas (GHG) emissions. It was developed from the late 1990s by the World Resources Institute (WRI) and the World Business Council for Sustainable Development (WBCSD), and provides a globally recognised framework for organisations to measure and manage their impact on the climate.

Why the GHG Protocol matters

As awareness of climate change grows, companies face increasing pressure to measure, manage and reduce their carbon footprint. The GHG Protocol offers a standardised framework that lets organisations:

• Understand their impact: a consistent methodology to identify and quantify emission sources.
• Set reduction targets: a clear baseline from which to define meaningful, achievable goals, including science-based targets.
• Report performance: a common language for emissions reporting that allows comparison between organisations.
• Comply with regulation: many governments and reporting frameworks build on the GHG Protocol.

The three emission scopes

The GHG Protocol classifies emissions into three scopes.

Scope 1: direct emissions

Scope 1 emissions are direct GHG emissions from sources owned or controlled by the organisation. Examples include:

• Fossil fuel combustion in owned or controlled facilities (boilers, furnaces, vehicles).
• Emissions from industrial processes.
• Fugitive emissions, such as refrigerant leaks.

Scope 2: indirect energy emissions

Scope 2 emissions are indirect emissions from the generation of purchased electricity, heat or steam consumed by the organisation. They occur physically outside the organisation's boundaries.

Scope 3: other indirect emissions

Scope 3 emissions cover all other indirect emissions across the value chain, both upstream and downstream. Examples include:

• Purchased goods and services.
• Transport and distribution (upstream and downstream).
• Business travel.
• Waste generated in operations.
• Use and end-of-life of sold products.

The accounting methodology

The GHG Protocol sets out a step-by-step method for GHG accounting:

1. Define the boundaries: set the organisational and operational boundaries for the inventory.
2. Identify emission sources: list all relevant sources within those boundaries.
3. Collect activity data: gather data such as fuel and electricity consumption.
4. Apply emission factors: convert activity data into emissions using appropriate factors.
5. Calculate emissions: add up emissions from all sources to obtain the total.

Standards and tools

The GHG Protocol has developed a suite of standards and tools, including:

• Corporate Standard: the core guidance for accounting and reporting corporate emissions.
• Corporate Value Chain (Scope 3) Standard: specific guidance for Scope 3 emissions.
• Product Life Cycle Accounting and Reporting Standard: for product-level footprints.
• Calculation tools: sector and cross-sector tools to estimate emissions.

Benefits of using the GHG Protocol

• Credibility: a globally recognised standard strengthens the credibility of GHG inventories and supports comparison.
• Better decisions: accurate measurement reveals where reductions will have most effect.
• Regulatory compliance: it provides the basis to meet mandatory reporting in many jurisdictions.
• Access to markets and finance: investors and customers increasingly expect transparent emissions data.

Relationship with other standards

The GHG Protocol works alongside other standards for measuring emissions:

• ISO 14064: requirements and guidance for quantifying, reporting and verifying an organisation's GHG emissions and removals.
• ISO 14067: the standard for quantifying the carbon footprint of products, which supersedes the older PAS 2050 specification.

The future of the GHG Protocol

The GHG Protocol is undergoing a major revision. Since 2024, technical working groups have been updating the Corporate Standard, the Scope 2 Guidance and the Scope 3 Standard, with input from the ISO community joining the process in 2026. A full draft of the revised Corporate Standard is expected to go to public consultation in mid-2026, with publication of the new edition anticipated by the end of 2027. The current standards remain the reference until the revised versions are adopted.

How Manglai applies the GHG Protocol

At Manglai we help companies measure their carbon footprint across Scope 1, 2 and 3 following the GHG Protocol, and prepare their sustainability reporting on solid, auditable data. Discover how Manglai can help you.