The Greenhouse Gas (GHG) Protocol is the global standard for measuring and reporting greenhouse gas emissions. Set up by the World Resources Institute (WRI) and the World Business Council for Sustainable Development (WBCSD), it defines Scopes 1, 2 and 3. IFRS S2, California's SB 253 and CDP all build on it. Its main standards are being revised.
The GHG Protocol is a set of standards, guidance and tools for measuring and reporting greenhouse gas emissions. It is used by companies, cities, governments and project developers.
It was started in 1998 as a partnership between WRI and WBCSD. Its Corporate Standard was first published in 2001 and revised in 2004. It created the idea of Scopes 1, 2 and 3, which is now used across almost all corporate climate reporting.
The GHG Protocol covers seven greenhouse gases: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur hexafluoride (SF6) and nitrogen trifluoride (NF3). All are converted to CO2e for reporting.
The GHG Protocol has several standards for companies. Each covers a different part of the footprint.
| Standard | Published | What it covers |
| Corporate Accounting and Reporting Standard | 2001, revised 2004 | Company-wide inventory, boundaries, Scope 1 and 2 reporting |
| Scope 2 Guidance | 2015 | Location-based and market-based reporting of purchased energy |
| Corporate Value Chain (Scope 3) Standard | 2011 | 15 categories of value chain emissions |
| Product Life Cycle Standard | 2011 | Emissions of individual products across their life cycle |
| Land Sector and Removals Standard | 2026 | Land use emissions, land use change and carbon removals |
The GHG Protocol also publishes free calculation tools for common sources such as fuel, transport and refrigerants.
Every GHG Protocol inventory should follow five principles: relevance, completeness, consistency, transparency and accuracy.
Our guide to assessing the materiality of your inventory shows how to apply them in practice.
Scope 1 is direct emissions from sources a company owns or controls. Scope 2 is emissions from purchased electricity, heat, steam and cooling. Scope 3 is all other indirect emissions in the value chain.
The Corporate Standard requires Scopes 1 and 2. Scope 3 is optional under the Corporate Standard, but many disclosure rules now require it. See GHG scopes 1, 2 and 3 explained for examples.
Before you sort emissions into scopes, you set your organisational and operational boundaries. The Corporate Standard allows three consolidation approaches: equity share, financial control and operational control. See determining your GHG inventory boundaries.
The GHG Protocol matters because most climate disclosure rules and frameworks require or rely on it. Using it means your numbers are comparable, auditable and accepted by regulators, investors and customers.
The benefits are practical: one set of rules across markets, clear guidance on data and factors, results that can be compared between companies and years, and a recognised basis for external assurance.
Climate targets only work if emissions are measured the same way. The latest UN figures show the world is still off track.
The UN Environment Programme's Emissions Gap Report 2025 projects warming of 2.3–2.5°C this century if countries fully deliver their national climate plans (NDCs), and 2.8°C under current policies. It finds that emissions must fall 55% below 2019 levels by 2035 to align with a 1.5°C pathway (UNEP, November 2025). A common standard lets companies set targets, track progress and show their share of those cuts.
Yes. The GHG Protocol is revising its Corporate Standard, Scope 2 Guidance and Scope 3 Standard through an independent standards board. Scope 2 changes, including stricter rules on matching clean electricity to use, went to public consultation in late 2025.
Until new versions are final and in force, the current standards apply. Our post on how the GHG Protocol is changing tracks the updates.
Dyno Nobel used Terrascope to complete its first global Scope 1 and 2 audit a year ahead of Australia's mandatory reporting rules. Its 1.6 million tCO2e Scope 1 and 2 footprint was externally assured.
On the Scope 3 side, Princes used the value chain view to find that its top five activities made up more than 60% of its emissions. Read the Princes case study.
Terrascope's corporate carbon footprint platform is built around GHG Protocol scopes, categories and principles.
To see how we approach a full inventory, read how to calculate GHG emissions. To estimate the effort of moving from spreadsheets, try the carbon accounting ROI calculator.
Want an inventory that meets the GHG Protocol? Talk to our team.
What is the GHG Protocol in simple terms? It is the global rulebook for measuring a company's greenhouse gas emissions. It says what to count, how to group it into Scopes 1, 2 and 3, and how to report it.
Who created the GHG Protocol? The World Resources Institute (WRI) and the World Business Council for Sustainable Development (WBCSD) set it up in 1998. Its Corporate Standard was first published in 2001.
Is the GHG Protocol mandatory? It is a voluntary standard, but many rules make it effectively required. IFRS S2 and California's SB 253 both require companies to measure emissions in line with it.
What is the difference between the GHG Protocol and ISO 14064? Both set rules for GHG inventories and are broadly compatible. The GHG Protocol is more widely used for corporate reporting and defines the three scopes. ISO 14064-1 is an international standard often used where verification against an ISO standard is preferred.
Does the GHG Protocol require Scope 3 reporting? No. Under the Corporate Standard, Scope 3 is optional. The separate Scope 3 Standard sets rules for companies that report it, and many disclosure rules now require it.
When will the new GHG Protocol standards apply? The GHG Protocol has not finalised the revised Corporate, Scope 2 and Scope 3 standards yet. Keep using the current versions until the new ones are published and their effective dates are confirmed.