What changed in the 2026 emission catalogue, and how to respond
MfE published the 2026 Measuring Emissions Catalogue on 29 May, replacing the 2025 guide most New Zealand emissions calculations have been running on. If you measure emissions in New Zealand voluntarily, or are regulated to do so under the CNGP or as a Climate Reporting Entity, these are the factors you'll be using this cycle.
Orange marks changes to act on; grey marks no real change.
Most of the changes are small updates flowing through refreshed source data. A handful will affect your footprint.
Waste to landfill
The municipal (Class 1) factors are the ones most organisations in New Zealand use. The catalogue shows that 94% of municipal waste in 2024 went to a landfill with gas recovery, so unless you know specifically otherwise, these are your factors. All 12 of these factors have increased by roughly 60% this cycle, largely because MfE improved the gas recovery rate assumption for municipal landfills with gas collection. If waste has been a large proportion of your emissions previously, this can be a big hit on your emissions reduction plan; if it hasn't, the change may make it one. You will need to check this one carefully.
Municipal (Class 1, with gas recovery) landfill factors: 2025 vs 2026
Document any significant change as a methodology-driven restatement rather than an operational change, and think carefully about whether it triggers a base-year recalculation under your organisational policy, in line with the GHG Protocol or ISO 14064-1.
Electricity methodology change
The purchased electricity table now includes 2010 and 2011 annual factors. If you're benchmarking against an older base year, this may be useful.
The 2024 annual factor is new, all four 2025 quarterly factors are new, and 21 historical factors have been revised, following a change in underlying source data from MBIE. Four annual factors were removed as part of this change. Some downstream factors shift as a result too, including transmission and distribution losses, working from home, and vehicles that run on electricity.
Fuel
MBIE, the source of the fuel data, has refreshed its fuel property data, coal demand data, gas factors and liquid fuel factors. This flows into vehicles, electricity generation, freight, heating and more. The fuel factors themselves haven't changed dramatically, but because so many other factors use fuel and electricity as their basis, they move as a consequence.
Travel
Almost every travel sub-category has changed. Domestic air factors are now sourced directly from Air New Zealand for medium and large aircraft. International air factors have been updated via DESNZ 2025, including revised radiative forcing (RF) multipliers; the catalogue continues to flag the genuine scientific uncertainty around RF, though including it remains industry best practice. Accommodation factors have been refreshed using Cornell HSBI 2025, with 14 factors added and 2 removed.
Most changes to light passenger vehicles flow from the fuel and electricity updates, but there was also a fix to how vehicles are grouped by year of manufacture. Taxis, staff mileage and rental cars all changed as a result.
What this means for your inventory
The catalogue is an additional guide to the GHG Protocol Corporate Standard and ISO 14064-1:2018. It sets out national average factors that organisations in New Zealand can use to measure and report their emissions. Acting on the 2026 changes follows the same process as previous years: refresh the factors that pertain to your organisation, then work through the changes above, waste, electricity, fuel and travel, to see which ones are significant enough to affect your figures. Keep a clear record of which year's catalogue produced each number.
Waste and electricity remain the priorities for most entities this cycle. The roughly 60% rise in municipal (Class 1) landfill factors and the revised electricity factors are the two changes most likely to move your numbers materially, if waste or electricity make up a large share of your footprint. Refrigerant factors have also changed on paper, but the change is cosmetic, previously blank CO2 fields being populated, so it needs no action.
What to do now
- Update your emission factor files to the 2026 MfE catalogue across all affected categories, with particular attention to municipal Class 1 landfill, purchased electricity, fuel-related factors and travel.
- Re-estimate municipal Class 1 landfill emissions using the updated 2026 factors, especially where waste is a material emissions source or may become one because of the increase.
- Review electricity-related calculations, including purchased electricity, transmission and distribution losses, working from home, and electric vehicle factors, where they are relevant to your inventory.
- Record the catalogue year and factor source used for each emissions category so that prior-year comparisons and methodology changes remain transparent.
- Assess whether any significant movement in reported emissions is methodology-driven and whether it triggers a base-year recalculation under your organisational policy, the GHG Protocol or ISO 14064-1:2018.
- If you assure inventories: scrutinise waste classification, electricity factor selection, travel factor updates, and disclosure of the catalogue year used.
How Opportune can help
We help corporates, councils and public sector organisations keep their greenhouse gas inventories accurate and defensible as the underlying factors change. For the 2026 update that means re-estimating the waste and electricity emissions that have moved most, refreshing factor files across every affected category, and documenting the catalogue year and methodology so prior-year comparisons hold up under scrutiny.
We also provide independent assurance and verification against the standards the catalogue points to, ISAE 3410 and ISO 14064-3:2019. If you report under the Financial Markets Conduct Act or participate in the Carbon Neutral Government Programme, independent assurance is a requirement rather than an option, and we can help you meet it or prepare for it.
To work through what the 2026 changes mean for your inventory, or to arrange assurance against them, get in touch with Opportune.
