The greenhouse gas protocol is the accounting framework most organisations use to measure and report the climate-warming gases they cause, from fuel burned on site to emissions further along their supply chains.
It is one of several topics under the what is a carbon footprint hub, which explains the wider idea of measuring emissions before trying to reduce them.
What the GHG Protocol is and who uses it
The GHG Protocol sets out standardised frameworks to measure and manage greenhouse gas emissions from private and public sector operations, value chains and mitigation actions. It grew out of a partnership between the World Resources Institute and the World Business Council for Sustainable Development, and it is maintained as a set of standards, guidance and calculation tools rather than as a law or a certification scheme. That distinction matters for anyone reading a sustainability report: saying that an inventory follows the protocol describes how emissions were counted, not how good or bad the results are.
Its reach is wide. The same page reports that in 2023, 97% of disclosing S&P 500 companies reported to CDP using GHG Protocol, which helps explain why the framework is often described as the common language of corporate emissions accounting. Many national and voluntary reporting programmes build their own rules on top of it.
This site is independent and informational. It is not part of the GHG Protocol, the bodies behind it or any reporting programme, and it does not issue, verify or sell anything. The official documents on the protocol’s own website are the reference for anyone preparing an inventory.
The core standards in the suite
The framework is a family of documents. The Corporate Accounting and Reporting Standard gives requirements and guidance for companies and other organisations preparing a corporate-level inventory. It applies equally to non-governmental organisations, government agencies and universities, not only to businesses. The first edition was published in 2001, according to the protocol’s history page.
Alongside it sit other standards for specific uses, and the protocol’s standards page lists them: a framework for city-wide inventories, a mitigation goal standard for countries and cities, a policy and action standard, a product standard for life cycle emissions, and the value chain standard used for indirect emissions. An organisation choosing between them starts from what it is measuring: its own operations, a product, a city or a policy.
Which gases are counted
The corporate standard covers seven greenhouse gases named under the Kyoto Protocol: carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, sulphur hexafluoride and nitrogen trifluoride, as set out on the corporate standard page. Carbon dioxide gets most of the attention, but methane from waste or livestock and fluorinated gases from refrigeration and electrical equipment can matter a great deal for some organisations.
Because the gases warm the atmosphere to different degrees, inventories normally express them in a single unit, carbon dioxide equivalent, so that totals can be added up and compared year to year. Readers who want the background on how each gas is weighted can look at the separate explainer on global warming potential, but the protocol’s own pages are the place to confirm which conversion values a given reporting programme requires.
Setting the organisational boundary
Before counting anything, an organisation must decide which operations belong in its inventory. The standard’s text explains that two distinct approaches can be used to consolidate emissions: an equity share approach and a control approach. Under the equity share approach, emissions follow the share of ownership in each operation. Under the control approach, an organisation counts all of the emissions from operations it controls, and it chooses between financial control and operational control as the test.
For a business that wholly owns everything it operates, the choice changes nothing. For companies with joint ventures, leased sites or franchises it can change the total noticeably, which is why the chosen approach has to be stated and applied the same way every year.
Direct, energy and value chain emissions
The protocol sorts emissions into three groups, usually called scopes. A plain-language walk-through is on the page about scope 1 2 and 3 emissions, so only the outline is given here.
Direct emissions come from sources the organisation owns or controls, such as boilers and company vehicles. Indirect emissions from purchased electricity, steam, heat and cooling were clarified by the Scope 2 Guidance, which also sets out eight quality criteria that contractual instruments must meet to be a reliable data source for the market-based method. All other indirect emissions, from purchased goods to the use and disposal of sold products, fall under the Corporate Value Chain Standard, which lets users account for emissions from 15 categories of activity upstream and downstream. The same page states that the majority of total corporate emissions come from this value chain group, which is why it is often the hardest and most important part of an inventory.
Principles and base years
A good inventory is less about a single clever calculation than about disciplined bookkeeping: a clear boundary, complete data and methods that stay stable.
The standard builds inventories on accounting principles: relevance, completeness, consistency, transparency and accuracy. In practice they mean that an inventory should include all material sources, use the same methods from year to year, and document its assumptions so that a reader can follow how the totals were reached.
Tracking change over time needs a fixed starting point, called a base year. The standard says that companies shall develop a base year emissions recalculation policy, so that an acquisition, a sale or a change of method does not make progress look better or worse than it really is.
Organisations that want to reduce emissions usually start by finding the largest sources in the inventory; the page on how to reduce business carbon footprint covers where to begin.
What the protocol does not do
The corporate standard has clear limits. It is designed to develop a verifiable inventory, but according to the corporate standard page it does not provide a standard for how the verification process should be conducted. It also states that it should not be used to quantify the reductions associated with mitigation projects for use as offsets or credits, because a separate project accounting protocol exists for that purpose.
The value chain standard is similarly careful. Its frequently asked questions say it is designed to enable comparisons of one company’s emissions over time and is not designed to support comparisons between companies, since differences in reported totals can come from methods, size or structure rather than performance.
An organisation that publishes climate claims based on an inventory should also check the advertising and consumer rules where it operates, because a claim can be misleading even when the underlying numbers are sound.
Frequently asked questions
Is the GHG Protocol a law?
No. It is a voluntary accounting framework, although some regulations and reporting programmes refer to it or build on it.
Does it apply to small organisations?
The corporate standard is written for companies and other organisations such as non-governmental organisations, government agencies and universities, and the protocol’s own materials present it as usable at any size.
Does following it make an organisation carbon neutral?
No. The protocol measures and reports emissions. Whether an organisation can describe itself in terms such as carbon neutral is a separate question that depends on other rules and evidence.
Who checks an inventory?
The corporate standard is designed to produce a verifiable inventory but leaves the verification method to others, so any third-party review follows a separate standard. Organisations that want assurance usually appoint an independent reviewer and say which standard that reviewer used.
