GHG Protocol Explained: The Standard Behind Carbon Accounting
If you've spent any time looking into carbon accounting, you'll have run into the term "GHG Protocol" almost immediately. It sits quietly behind nearly every framework a UK business is likely to encounter — UK SRS, SBTi, TCFD — yet it rarely gets explained on its own terms. Understanding it properly makes every other compliance requirement easier to navigate.
What the GHG Protocol Actually Is
The Greenhouse Gas Protocol is a set of accounting standards developed jointly by the World Resources Institute and the World Business Council for Sustainable Development. First published in 2001, it was created to solve a basic problem: businesses, governments and investors needed a consistent way to measure and report greenhouse gas emissions, so that numbers from one organisation could be meaningfully compared to another's.
It isn't a piece of legislation and it isn't specific to any one country or industry. It's closer to an accounting standard — a rulebook for how emissions should be categorised, calculated and reported, so the resulting figures are reliable and comparable. This is precisely why nearly every other framework builds on it rather than reinventing its own methodology.
The Three Scopes
The GHG Protocol's most widely recognised contribution is its division of emissions into three scopes.
Scope 1 covers direct emissions from sources a business owns or controls — company vehicles, on-site fuel combustion, refrigerant leaks from owned equipment. These are typically the most straightforward to measure, since the activity data usually already exists in fuel receipts, mileage logs or meter readings.
Scope 2 covers indirect emissions from purchased energy — electricity, heat, steam or cooling bought from a supplier. The emissions physically occur at the power station, not on-site, but because the business is the one consuming the energy, it's accountable for them.
Scope 3 covers everything else in the value chain: purchased goods and services, business travel, employee commuting, waste, and — for most businesses — the emissions embedded in what they sell once it leaves their hands. This is where most of a typical SME's footprint actually sits, and where measurement gets genuinely difficult, since it depends on data from suppliers and customers rather than internal records.
Why This Structure Matters for Reporting
The scope structure exists to prevent double-counting and to make emissions data auditable. If every business reported emissions however it liked, comparing a supplier's numbers against a competitor's, or checking a claimed reduction against previous years, would be close to impossible.
This is also why the GHG Protocol underpins so much else. UK SRS reporting requirements are built around Scope 1, 2 and 3 disclosure. CDP questionnaires are structured around the same scopes. SBTi target-setting methodology requires a GHG Protocol-aligned baseline before a science-based target can even be validated. None of these frameworks ask businesses to measure emissions differently — they ask businesses to report GHG Protocol-calculated figures in a particular format, to a particular audience, on a particular schedule.
Where Businesses Tend to Get Stuck
In practice, the theory is rarely the hard part. Scope 1 and 2 are usually manageable with existing utility and fuel data. Scope 3 is where most SMEs stall — not because the categories are conceptually difficult, but because gathering fifteen categories' worth of supplier and customer data, choosing the right calculation approach for each, and keeping emission factors current is a genuinely large undertaking without the right process or tooling behind it.
This is usually the point where a spreadsheet-based approach starts to show its limits, and where purpose-built carbon accounting software earns its keep — not by changing the methodology, but by making a GHG Protocol-aligned calculation consistent, auditable and repeatable year after year.
The Takeaway
The GHG Protocol isn't an extra compliance burden sitting alongside frameworks like UK SRS or CDP — it's the foundation they're all built on. Understanding the three scopes, and why the distinction between them exists, makes every downstream reporting requirement considerably less daunting. Get the GHG Protocol fundamentals right, and the rest of the compliance landscape starts to look a lot more like variations on a theme rather than separate problems to solve.