Skip to content
English
More support
  • There are no suggestions because the search field is empty.

Updating Carbon Factors 2026

What are carbon factors and how will the update affect your data?

Updating Carbon Factors 2026 What are carbon factors and how will the update affect your data?

What are carbon factors?

There are several greenhouse gases (GHGs) that have a warming effect on the planet when emitted, with carbon being the most widely recognised. These are expressed as carbon dioxide equivalent emissions (CO2e).

Some things to know about CO2e:

  • It's usually measured in tonnes (tCO2e) but in some instances, kilograms are used (kgCO2e).
  • To calculate the carbon footprint of a particular activity we multiply 'activity data' by an emissions factor to equal your CO2e. For example:

Activity Data x Carbon Factor = CO2e

  • Emissions factors are always expressed in kgCO2e, such as kgCO2e/mile (kgCO2e per mile) for transport. For example, transport is calculated using the following equation:

Distance travelled x carbon factor of vehicle engine type = CO2e

So for an average petrol car, this looks like this:

10 miles x 0.33875 kgCO2e/mile = 3.3875 kgCO2e

Where do our carbon factors come from?

In TRACE, all of our data is scientifically backed and verified and as such, our calculations rely on accurate carbon factors. As technology advances and standard practice changes, the carbon factors will also need to change in order to represent the most up-to-date emissions associated with an activity. Given the differences between countries, the carbon factors may need to change based on this too.

TRACE uses a mix of accredited bodies to generate the most accurate factors including using the Department for Energy Security and Net Zero (DESNZ) for energy factors in the UK, with equivalent bodies providing figures within each country.

Other modules will use a mixture of life-cycle analysis (LCA), averages pulled from global databases and modelling as a way of determining factors for different material and meal types.

How will the update impact my data?

The update retrospectively changes the factors for every event held in 2026, and for any 2026 data already in the platform. Your 2022, 2023, 2024 and 2025 events keep the factors from those years.

The changes happen behind the scenes in the calculations, so they'll lead to small changes in your final emissions rather than dramatic ones. You're most likely to spot them in your combined dashboard, where the cumulative effect adds up. That figure is the most accurate value for your 2026 event emissions.

This doesn't mean reports based on earlier data are wrong or need redoing. They used the most up-to-date data available at the time, backed by externally validated methodology. Email support@traceyour.events if you'd like more detail on our methodology.

Has anything notable changed?

Not much, compared with last year. Last year the air travel factors moved substantially; this year most factors have barely shifted. A few are worth knowing about, either because the percentage is large or because the reason behind the change is worth understanding.

International rail, up 154% per passenger. This is the biggest percentage change this year, but before it alarms anyone: rail is a small contributor for most events, so even a jump this size tends to have a modest effect on overall results. The increase comes from changes in service patterns and rolling stock use. The old factors were built on figures from before the COVID pandemic, so this is really a data update catching up, not international rail becoming more polluting in direct comparison to last year.

UK electricity, down 26%. Grid electricity has dropped by roughly a quarter as the UK grid keeps decarbonising. Transmission and distribution (T&D) losses are down too.

Electric vehicles, still falling. EV factors keep dropping year on year, helped along by the lower electricity factors above. For some classes the fall is as much as 37%.

Underground, down 45%. Underground factors have fallen sharply, also on the back of the lower grid electricity feeding into rail traction.

HGVs, up around 10%. Heavy goods vehicle factors are up by roughly 10% depending on class, mostly because average loads have been recalculated, which changes the emissions attributed per tonne-kilometre.

When you talk these numbers through with clients, a short note on the larger movements helps with transparency. Where a significant change is down to updated data rather than a real shift in the activity, say so. It's still a reduction, but be honest about where the reduction came from. Do this by reporting a few non-carbon metrics alongside the footprint, such as number of journeys, total mileage, or mode split, so year-on-year comparisons have more meaning.