The minute
- Scope 1 and 2 tend to be the easiest to measure, since they come from data the company already has (fuel, electricity bills)
- Scope 3 requires categorizing the value chain (suppliers, freight, travel, product use) and prioritizing the highest-weight categories first
- State the method used and what was left out, instead of faking a precision that doesn’t exist
Why it matters: The difference between an inventory that survives an audit and one that doesn’t is almost never scope 1 or 2, it’s how scope 3 was handled.
Scope 1: what the company burns directly
Own fleet, boilers, generators. The data is usually already on the fuel invoice, the simplest part of the inventory.
Scope 2: purchased energy
Electricity consumed, multiplied by the grid’s emission factor (in Brazil, published by MCTI, usually low because the mix is mostly renewable).
Scope 3: the big, hard part
Covers 15 possible categories under the GHG Protocol, from suppliers to product disposal. For services and retail, it’s usually 70 to 90 percent of the real footprint. Prioritize the highest-weight categories first (usually purchased goods and freight) instead of trying to cover everything at once.
How to report without inflating or underestimating
State explicitly which method you used (real data vs. spend-based estimate) and which categories were left out this round. An inventory with a declared gap is more credible than a round number with no explanation.
Frequently asked questions
Do I need to report all 15 scope 3 categories in year one?
No, start with the categories most relevant to your sector and expand scope in later rounds.
Is scope 3 mandatory?
It depends on applicable regulation (like the CSRD) and client or investor requirements; not every company is legally required to, but market pressure is growing.
What’s the difference between an inventory and a carbon footprint?
The inventory is the structured measurement process; the footprint is the final number that comes out of it.
Read next: what scope 1, 2 and 3 emissions are.
Read next: what the GHG Protocol is.