We always strive to correct any errors that are discovered in previous versions of the Calculator. When we do, we will share information here.
1st April 2025 - annual update corrections.
Overview
Each year we conduct a thorough check of each of our emissions factors to ensure that they are accurate and have been calculated correctly. Unfortunately errors will occur as our system is in constant use and constantly evolving, and therefore during this update period we will also issue some corrections.
When we make a correction, we ensure to check all previous emissions factors are corrected, which means if you recalculate an old report, you may see that the emissions change. We have corrected the following items in this update:
- Plant-raising media (all items drawn from reference 16 in our references list) had previously used an offsetting approach to calculate emissions factors, taking into account carbon sequestration. As this was identified to not be GHG protocol compliant, now the Life Cycle Analysis - LCA approach is used instead. This has lead to an increase in these emissions factors.
- The carbon sequestration associated with growing perennial stone fruit, nuts and miscanthus was being underestimated. This value has been corrected so increased sequestration is seen resulting from these crops on an annual basis.
- Categories in Distribution > Road | Sea | Rail | Air freight used an incorrect kilometer to miles conversion, meaning the emissions associated were being underestimated. In Public transport > Bus, this conversion was omitted, meaning these emissions were being also underestimated.
- Under specific car fuel use entered by miles and miles per gallon (mpg), emissions factors were being reported per litre rather than per gallon. This has been corrected by applying a conversion factor, but means emissions associated with this mode of entry have increased.
- ForFarmers feeds were updated in 2024, however the change was overridden, so these factors have been re-implemented.
- Biomass crops > Hemp had previously contained an emissions factor that assumed roots were renewed every 3 years rather than being an annual crop. It is now an annual crop meaning the emissions associated with root residue renewal have increased.
- The emissions factors for derived fertilisers had been underestimating the emissions from N, P & K due to an error in the way constituent components were implemented as a percentage of the total product. A correction to how the emissions factors are generated has rectified this error but means emissions associated with derived fertilisers have increased.
- An individual error with Countryside Stewardship scheme GS4: Legume and herb-rich swards meant the modelled sequestration was incorrect and this error has been rectified.
- The term ‘Offsets’ was previously used to describe carbon sequestration within the tool and on the results page, this terminology has now been updated to ‘Removals’.
You can read about other aspects of the April 2025 update in the "What is New in 2025" document on our resources page.
What should I do?
If you would like to update your reports to match the corrected vales you can go to your report summary page and hit recalculate. This will reprocess the report and give you up to date values including the corrections. This is a permanent change, so if you want to keep an old version of your report for legacy purposes you should make a copy of the report first and use the 'Lock' button to prevent it being recalculated.
7th October 2024 - Agricultural, horticultural and vine crops emissions 2000-2024
What happened?
Until 2024, the Farm Carbon Calculator assumed an average approach to crop residue removal for each type of crop. It also used IPCC and GHG inventory standard values for the N content of those crops. We have improved our methodology to allow increased granularity between different crops (e.g. between different soft fruits such as strawberries and raspberries) to give more accurate emissions estimates for each crop. We have also provided options around management practices such as removing all (or none) of the crop residues (straw/ spent plants) to improve the accuracy of emissions estimates. The estimates for emissions from the majority of crop plants has reduced, however for most soft and top fruit it has increased (because there were previously no high-quality estimates for these crops). It is important that these improved estimates are available on the tool for all reports, so any report created after 7 October 2024 will use the updated emissions factors for crops.
Existing reports will not be altered (updated) until you add, edit or delete a "crops" item.
What should I do to update reports?
You need to keep copies of your reports as they were originally submitted. So, for any reports already completed (before 2024-10-07):
1. Use the "lock report" button on the results page THEN
2. Make a copy of each of those reports. The copying process will re-submit each report to the calculations (using the corrected factors).
Alternatively, if you don't need the original version of the report, you can use the orange "recalculate" button on the results page to access the corrected emissions factors.
11th April 2024 - Distribution emissions 2022-2023
What happened?
When we obtain the emissions factors for freighting goods, they are available from BEIS [64] in a number of formats (per tonne.km, per km and per mile). We need the emissions factor in tonne.miles so that UK users can enter the distance in miles, number of journeys and tonnes transported. In the May 2023 update (factors affecting reports ending 2022-09-01 to 2024-04-01) the emissions factors obtained from BEIS had not been properly converted to kgCO2e per tonne.mile by our team and as a result, distribution emissions in the Calculator were over-estimated. We apologise for the inconvenience.
What should I do?
You need to keep copies of your reports as they were originally submitted. So, for any reports with distribution from 2022 or 2023 (end date 2022-09-01 to 2024-04-01):
1. Use the "lock report" button on the results page THEN
2. Make a copy of each of those reports. The copying process will re-submit each report to the calculations (using the corrected factors).
Alternatively, if you don't need the original version of the report, you can use the orange "recalculate" button on the results page to access the corrected emissions factors.