The GHG Protocol (Greenhouse Gas Protocol)

Whichever spelling you come across, it's the same framework, developed by the World Resources Institute (WRI) and the World Business Council for Sustainable Development (WBCSD) [1].

In this article we explain what the GHG Protocol actually is, how Scope 1, 2 and 3 fit together, which tools are part of it, and why the protocol has become the foundation that almost all other climate regulations build on. It's written for anyone working in sustainability, finance or management who needs to get a handle on their company's carbon footprint, whether it's voluntary or a requirement under the CSRD.

What is the GHG Protocol?

The GHG Protocol is a global framework for measuring, reporting and managing greenhouse gas emissions. It covers seven greenhouse gases: carbon dioxide, methane, nitrous oxide, HFCs, PFCs, sulphur hexafluoride and nitrogen trifluoride (NF3). NF3 was only added in 2013 [2], so if you come across sources talking about "six gases", that's the old figure.

The framework covers emissions from both your own operations and the entire value chain, direct and indirect. It underpins most of the sustainability reports and regulations that exist today, from CDP and the Science Based Targets initiative to the CSRD and the Voluntary EU standard VS (formerly VSME).

Purpose and vision

The GHG Protocol's mission is to develop the most credible and widely used standards for climate accounting and to get as many organisations as possible to actually use them. The vision is that if everyone, in both the private and public sectors, reports their emissions, it becomes easier to achieve the reductions the Paris Agreement requires, at the pace that's actually needed.

So far, that hasn't been enough. Global warming has already been above 1.5 degrees for the past three years, and the UN Environment Programme (UNEP) notes that it's now unavoidable that warming will permanently pass that limit, something expected to happen within a few years, peaking at around 1.8 degrees [3]. That doesn't make emissions reporting any less important. On the contrary: the better the data the world has, the faster we can bend the curve back down.

How the standard came about

The story begins in the late 1990s, when it became clear that the world lacked a common way of measuring companies' climate impact. In 1998, WRI published the report Safe Climate, Sound Business, which pinpointed exactly that problem [3]. A core group was formed with representatives from business, including Shell, Norsk Hydro and Tokyo Electric, and from environmental organisations such as WWF, the Pew Center on Global Climate Change and The Energy Research Institute [3], to develop a standard that was both scientifically sound and practically useful.

In 2001, the first version of the GHG Protocol Corporate Standard was published [3]. It has since been built on with guidance on, among other things, purchased energy and emissions in the value chain.

The toolbox: standards, guidance and calculation tools

The GHG Protocol is more than one standard. It's a collection of tools, and the most widely used parts are:

• Corporate Standard: the foundation for climate accounting in your own operations

• Scope 2 Guidance: how to report indirect emissions from purchased energy

• Corporate Value Chain (Scope 3) Standard: emissions across the whole value chain

• Product Life Cycle Standard: a product's climate impact across its entire life cycle

• Mitigation Goal Standard: how to measure progress towards climate goals

• Policy and Action Standard: the climate benefits of policies and actions

• GHG Protocol for Cities: emissions reporting for municipalities

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Which emissions are actually yours?

Before you can report anything, you need to decide which parts of the business count as "yours": which companies, facilities and processes you own or control. The GHG Protocol gives you two ways to draw the line: equity share, where you count emissions in proportion to how much you own, or control (financial or operational), where the whole operation counts if you have decisive influence, regardless of ownership share [4].

The choice affects what ends up in Scope 1 and 2 versus Scope 3, and it should be applied consistently year after year so that you can compare over time.

Scope 1, 2 and 3: what's the difference?

Under the GHG Protocol, emissions are divided into three categories, known as scopes:

• Scope 1: direct emissions from things you own or control yourself, for example your own vehicles or boilers.

• Scope 2: indirect emissions from purchased electricity, heat, steam or cooling.

• Scope 3: all other indirect emissions in the value chain, both upstream (for example purchased goods) and downstream (for example how customers use what you sell).

Reporting emissions in Scope 1 and 2 is now mandatory under most major regulations. Scope 3 is still voluntary in some contexts, even though it's often the largest part of a company's total climate impact [5], and at the same time the hardest to map, since the data comes from suppliers and customers rather than your own operations.

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A global impact

The GHG Protocol is now the world's most widespread framework for climate accounting, and it's used by both the private and public sectors. According to CDP (formerly the Carbon Disclosure Project), 92% of Fortune 500 companies were already using the protocol in 2016, directly or through a programme based on it [1]. In 2023, 97% of the S&P 500 companies reporting to CDP said they follow the GHG Protocol [5].

Cities and countries are on board too. Through the Global Covenant of Mayors for Climate & Energy, which the earlier Compact of Mayors merged into in 2016, hundreds of cities have committed to reporting their emissions according to the GHG Protocol [6].

How the standards are developed

One reason the GHG Protocol has had such an impact is the open process behind it. New standards are developed together with business, civil society, academia and public authorities, through a steering committee that takes strategic decisions, an Independent Standards Board that reviews and approves new standards, and several technical working groups with experts in different areas [7].

What's happening right now?

Mapping emissions in global value chains is still difficult, especially Scope 3, and the demands for transparency and verifiability are growing. Since 2025, the GHG Protocol and ISO have been working together on a joint, consolidated standard that merges the Scope 1, 2, 3 and AMI standards with ISO 14064-1 [8], with the aim of making calculations simpler and more comparable.

The joint, consolidated standard from the GHG Protocol and ISO is expected to go out for public consultation in the second quarter of 2027, with publication planned for the fourth quarter of 2028. The timeline isn't fully settled yet, but it's the latest plan approved by both organisations' boards.

Summary: why the GHG Protocol matters

The GHG Protocol, or Greenhouse Gas Protocol as it's also known, has laid the foundation for how companies and organisations around the world report their greenhouse gas emissions. By dividing emissions into clear categories, and combining scientific rigour with practical usability, the protocol provides tools that actually make a difference. It's not just about measuring, but about being able to act.

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