Greenhouse Gas Protocol (GHG Protocol)
The Greenhouse Gas Protocol (GHG Protocol) is the world's most widely used standard for corporate greenhouse gas accounting. It defines how companies should measure, categorize, and report their greenhouse gas emissions in a consistent way, and forms the methodological foundation that makes greenhouse gases, meaning gases in the Earth's atmosphere that absorb and re-emit infrared radiation and thereby contribute to the anthropogenic greenhouse effect, measurable and comparable in corporate practice in the first place.
Origins and history of the GHG Protocol
The GHG Protocol was developed in the late 1990s by the World Resources Institute (WRI) and the World Business Council for Sustainable Development (WBCSD) through a broad multi-stakeholder partnership involving businesses, non-governmental organizations, governments, and other institutions. The goal was to create an internationally consistent standard for measuring and disclosing corporate greenhouse gas emissions, after numerous inconsistent accounting approaches had previously existed side by side.
The three scopes: structure of the Corporate Standard
At the core of the framework is the Greenhouse Gas Protocol Corporate Accounting and Reporting Standard, first published in 2001 and revised in 2004. It divides a company's greenhouse gas emissions into three categories: Scope 1 covers direct emissions from sources owned or controlled by the company, such as its own combustion equipment or vehicle fleets. Scope 2 covers indirect emissions from purchased energy such as electricity, heat, or steam. Scope 3 captures all other indirect emissions along the upstream and downstream value chain, such as those from purchased goods, transportation, the use of sold products, or business travel.
Supplementary standards: Scope 2, Scope 3, and the Product Standard
The GHG Protocol has since been expanded with several complementary frameworks: the Scope 2 Guidance, published in 2015, introduced the distinction between the location-based and market-based accounting methods for purchased electricity. The Corporate Value Chain (Scope 3) Accounting and Reporting Standard, published in 2011, defines 15 Scope 3 categories and specific calculation approaches for what is often the most complex and emission-intensive part of the inventory. The GHG Protocol Product Standard, in turn, together with ISO 14067, forms the methodological basis for calculating Product Carbon Footprints for individual products.
The GHG Protocol as the basis for CSRD, CDP, and SBTi
The GHG Protocol today forms the methodological foundation that most other frameworks are built on: European sustainability reporting under CSRD and ESRS E1, the Carbon Disclosure Project (CDP), the Science Based Targets initiative (SBTi), and numerous national and voluntary climate initiatives all rely on the scope structure and calculation logic of the GHG Protocol as the implicit benchmark for the credibility of corporate greenhouse gas inventories.
Applying the GHG Protocol in corporate practice
In practice, applying the GHG Protocol means that all emission sources must be correctly assigned to the three scopes, consistent system boundaries defined, and emission factors documented transparently. Corporate Carbon Footprint software built from the ground up around the GHG Protocol helps companies capture Scope 1, Scope 2, and Scope 3 data in a structured way and consolidate it automatically into an audit-ready greenhouse gas inventory. A holistic carbon accounting solution also eases the transition from pure emissions tracking to concrete reduction measures.
In practice, more and more companies are turning to AI-powered data processing to automate the mapping of activity data to emission factors required under the GHG Protocol, detect data gaps, and streamline the demanding annual update of the greenhouse gas inventory, without compromising methodological consistency with the standard.
Criticism and the ongoing revision of the standard
Despite its widespread use, the GHG Protocol is also subject to criticism: in particular, the market-based accounting method for Scope 2, which takes into account the purchase of energy attribute certificates, has been criticized for not always adequately reflecting the actual physical emissions impact. The data quality of many Scope 3 categories, which often relies on generic industry-average figures rather than primary supply chain data, is also considered one of the biggest methodological weaknesses in current practice.
Against this backdrop, the GHG Protocol launched a multi-year public consultation process in 2023 to revise the Corporate Standard and the Scope 2 Guidance, aiming, among other things, to clarify the market-based method, the treatment of power purchase agreements (PPAs), and the boundaries with other frameworks. Companies should keep an eye on this revision process, as it may lead to new requirements for their own greenhouse gas accounting in the medium term.
Even though the GHG Protocol itself is not law but a voluntary industry standard, it has established itself over two decades as the de facto foundation for nearly all corporate climate accounting, and forms the basis on which today's regulatory reporting obligations such as CSRD and ESRS E1 are methodologically built.
