# My buyer asks for a base year and my bank asks for a baseline. Does the Greenhouse Gas Protocol treat them as the same?

Canonical: https://senseible.earth/answers/base-year-vs-baseline-greenhouse-gas-protocol

No. The Greenhouse Gas (GHG) Protocol Corporate Standard says a base year compares emissions over time, while a baseline is mostly used for project accounting and is a hypothetical scenario of emissions without the project. Lenders often use baseline loosely, so ask what they mean.

## The standard's own wording

In a note to chapter 5 the standard says base year emissions should be differentiated from the term baseline, which is mostly used in the context of project-based accounting. The base year focuses on a comparison of emissions over time, while a baseline is a hypothetical scenario for what GHG emissions would have been in the absence of a GHG reduction project or activity.

## In practice

- Buyer or questionnaire: my reading is that base year means a past year of real emissions, calculated from records, that later years are compared with. It gets recalculated after structural changes.
- Project or carbon credit: baseline is a what-if scenario, not a measured year.
- Lender: my reading is that many lenders use baseline to mean your actual energy use and emissions in the months before a project, which is a measured record and closer to a base year. Ask the loan officer which one they want, and send twelve months of actuals either way.

## Do not mix them up in one document

A saving claimed against a hypothetical baseline cannot be checked against a bill, but a saving against last year's actual use can. Label each figure as actual, base year or baseline scenario, and say how it was built.

## Example: one furnace upgrade, two numbers

- Base year, actual: financial year 2024-25 furnace oil 60,000 litres, measured from invoices.
- After the project, financial year 2025-26: 48,000 litres. Measured change: 60,000 minus 48,000 = 12,000 litres, 20%.
- A baseline scenario instead asks what use would have been without the project, for example 62,000 litres at higher output. The saving is then 62,000 minus 48,000 = 14,000 litres, 22.6%, and rests on an assumption.

Litres and the 62,000 scenario are example numbers.

## What Senseible does here

Senseible reads fuel invoices and electricity bills into monthly records, so the litres, kilowatt hours and months behind each year's figure stay on file. It does not set your recalculation policy or decide what counts as significant.

- [Carbon baseline before a green loan application](https://senseible.earth/answers/carbon-baseline-before-green-loan-application)
- [How to choose a base year](https://senseible.earth/answers/how-to-choose-base-year-carbon-inventory)
- [Loan baseline after growth](https://senseible.earth/answers/sll-baseline-recalculation-after-growth)
- [Green loan readiness check](https://senseible.earth/green-loan-check)

Sources: [GHG Protocol, A Corporate Accounting and Reporting Standard (Revised Edition), chapters 5, 6, 7, 9 and 10](https://ghgprotocol.org/sites/default/files/standards/ghg-protocol-revised.pdf)

Last reviewed 2026-11-06. The definitions are from chapter 5 of the Corporate Standard. How a lender uses the word baseline is my reading, so confirm it with the lender.