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How can I analyse the change in my emissions year on year?

Trace does not include a granular year on year analysis in your subscription. However, you can perform a detailed comparison yourself using the audit reports available for any published inventory on the Pro plan and above.

Many customers want to understand how their emissions change year on year. This is a common and sensible question, especially for internal reporting, target tracking and external disclosure.

This article explains how to analyse the changes yourself and how to interpret what you see.

First, some important context

It is completely normal for carbon inventories to change year on year.

Changes are usually driven by a combination of:

  • Changes in activity, such as energy use, travel, purchasing or headcount

  • Changes in emissions factors as datasets are updated or improved

Because of this, a year on year comparison should always look at both activity data and emissions factors, not just total emissions.

For more detail on factor updates, see our separate article: Why have the emissions factors changed?

Step 1. Download the audit reports for each year

To compare inventories, start by downloading the audit report for each published inventory you want to analyse.

  • Audit reports are available on the Pro plan and above

  • Download the reports for both years you are comparing

  • Make sure you are comparing final, published inventories rather than drafts

The audit report provides a full breakdown of input data, emissions factors and calculated emissions.

Step 2. Compare at the scope level

Begin with a high level comparison (you can do this in the MEASURE dashboard by toggling between measurement periods at the top):

  • Compare total Scope 1, Scope 2 and Scope 3 emissions year on year

  • Identify which scopes have increased or decreased

  • Focus your deeper analysis on the scopes with the largest changes

This helps you quickly understand where the main movements are occurring.

Step 3. Analyse changes by sub category

Next, look within each scope.

  • Compare emissions by sub category, such as electricity, natural gas, business travel, purchased goods and services

  • Identify which sub categories are driving the changes

  • Check whether changes are broad based or concentrated in a small number of areas

Most year on year variation usually comes from a few key categories rather than the entire inventory.

Step 4. Review changes at the detailed line item level

For categories with material movement, go deeper.

  • Compare individual line items in the audit report

  • Look at changes in quantities, such as kWh, litres, kilometres or spend

  • Look at changes in emissions factors applied to those same activities

This level of detail is where the real explanation usually sits.

Step 5. Separate activity change from emissions factor change

A critical part of any year on year analysis is understanding what has actually changed.

Ask the following questions:

  • Did the activity increase or decrease?

  • Did the emissions factor change?

  • Did both change at the same time?

Examples:

  • Higher emissions from similar activity level often point to updated emissions factors

  • Lower emissions with similar activity may reflect cleaner grids or improved datasets

  • Higher activity with stable factors usually reflects business growth or operational change

This distinction is essential for accurate interpretation and communication.

How to communicate year on year changes internally and externally

When explaining changes in emissions, clarity and transparency matter more than precision.

We recommend:

  • Clearly stating that year on year movements reflect both activity changes and factor updates

  • Separating operational changes from methodological changes wherever possible

  • Avoiding over interpretation of small movements caused by factor updates

  • Using plain language rather than technical carbon accounting terms

For external reporting, it is good practice to:

  • Note when inventories have been recalculated using updated emissions factors

  • Explain that this improves accuracy and comparability over time

  • Emphasise trends rather than single year movements

Need help with year on year analysis?

If you would prefer Trace to prepare a year on year comparison for you, we are happy to help.

  • This service is available on request

  • We can provide a clear breakdown of activity versus emissions factor impacts

  • We can support internal briefings or external disclosures if needed

Please contact your Trace representative or reach out to support to discuss options.