The headline number
Your total footprint is expressed in tonnes of CO₂e for the assessment period. CO₂e rolls every greenhouse gas, including carbon dioxide, methane, and refrigerants, into one comparable unit, so a single figure can describe the whole footprint. Two things to keep in mind:- The number is meaningless without its boundary. “120 tCO₂e” says nothing until you know which period and which operations it covers. When you share the number, share the boundary with it.
- Direction matters more than the absolute figure. Year-on-year movement and the split between categories drive decisions. The raw total is mostly for reporting.
The scope breakdown
Results split across Scope 1, 2, and 3 under the GHG Protocol. For most service businesses, events, and SMEs, expect Scope 3 to dominate, often by a wide margin. That is normal, not a data error. It reflects that most modern organisations’ impact sits in what they buy, not what they burn. If Scope 1 and 2 look small, that is usually accurate. If Scope 3 looks small, suspect a coverage gap before you celebrate: check that your reporting period is complete and that your largest supplier categories actually made it in.The category breakdown
This is the view that drives action. Categories such as electricity, flights, freight, purchased goods and services, and waste show where the footprint actually comes from, and they are almost always concentrated. A handful of categories typically account for most of the total. How to work with it:- Identify your top three categories. They are your reduction agenda. Effort spent anywhere else has limited payoff until these move.
- Check data quality on those three first. If a top category is running on spend-based estimates, upgrading it to activity data is the single best accuracy improvement available to you.
- Ignore the long tail, deliberately. Categories contributing a fraction of a percent do not warrant better data or reduction effort yet. Concentration is your friend.
Comparing over time
Once you have run more than one assessment, comparisons unlock:- Year-on-year for organisations. Is the footprint moving in the right direction, and which categories drove the change?
- Event-to-event for recurring events. The most useful benchmark an organiser has is its own previous edition.
Watch for boundary changes when comparing periods. If you added a site, an entity, or a new data source between assessments, the totals are not directly comparable. Compare the categories that were consistently measured instead.