What are Scope 1, 2 and 3 Emissions?
A clear explanation of the three scopes of greenhouse gas emissions used in carbon reporting — and why Scope 3 is the hardest and most important for most businesses.
Key Takeaways
- Scope 1 covers direct emissions from sources you own or control.
- Scope 2 covers emissions from purchased energy.
- Scope 3 covers all indirect emissions in your value chain and is typically the largest category.
Scope 1 and Scope 2 explained
The Greenhouse Gas Protocol divides carbon emissions into three scopes. Scope 1 covers direct emissions from sources owned or controlled by your business — for example, gas boilers, company vehicles running on diesel, or industrial processes on site. Scope 2 covers indirect emissions from the generation of purchased electricity, heat or steam. If you buy renewable electricity from a certified green tariff, your Scope 2 emissions can be significantly reduced. Scopes 1 and 2 are relatively straightforward to measure and are the starting point for most business carbon footprints.
Scope 3 — the biggest challenge
Scope 3 covers all other indirect emissions in your value chain — both upstream (your suppliers) and downstream (your customers' use of your products). For most businesses, Scope 3 is by far the largest category, often representing 70–90% of total emissions. It includes purchased goods and services, business travel, employee commuting, logistics, product use and end-of-life disposal. Scope 3 is harder to measure because it requires data from third parties, but it is increasingly required by large corporate customers and net zero frameworks.
Why the scopes matter for SMEs
Even if you are not required to report your emissions today, understanding the three scopes helps you prioritise action. Reducing Scope 1 cuts your direct operational costs (less fuel, less gas). Switching to renewable energy addresses Scope 2. Engaging your supply chain and changing procurement choices starts to tackle Scope 3. Large customers who must report their own Scope 3 emissions will ask their suppliers — you — for data. Getting familiar with scope-based thinking now means you are ready when that request arrives, rather than scrambling to respond.