2025 UK greenhouse gas emissions: provisional figures - methodology summary
Published 2 April 2026
© Crown copyright 2026
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This publication is available at https://www.gov.uk/government/statistics/provisional-uk-greenhouse-gas-emissions-statistics-2025/2025-uk-greenhouse-gas-emissions-provisional-figures-methodology-summary
Introduction
This document summarises how the provisional 2025 UK greenhouse gas (GHG) emissions estimates were derived, including the quarterly and temperature adjusted estimates that are included in this publication. The estimates show UK territorial GHG emissions, meaning GHG emissions that occur within the UK’s borders, and are presented on a ‘by source’ basis, meaning that emissions are attributed to the sector that emits them directly. The annual GHG emissions estimates for years up to 2024 in this publication match those in the 2024 final UK greenhouse gas emissions statistics and information about how those estimates were produced can be found in that publication.
The Department for Energy Security and Net Zero (DESNZ) currently publishes final UK GHG emissions estimates 13 months after the end of the reference year. However, a more timely provisional estimate of UK GHG emissions is made at the end of March, 3 months after the end of the reference year. The provisional estimates are based on provisional energy use statistics published in Energy Trends (for energy use GHG emissions), and the latest published Energy and Emissions Projections (EEP, for other GHG emissions).
For the purposes of reporting, we allocate GHG emissions into Territorial Emissions Statistics (TES) sectors[footnote 1]. The provisional statistics include breakdowns by these high-level TES sectors and type of fuel. In addition, the buildings and product uses TES sector is disaggregated into residential buildings, commercial buildings, public buildings, and other buildings and product uses TES subsectors. Further breakdowns are not available in the provisional statistics.
The provisional UK GHG emissions statistics publication also includes:
- Quarterly GHG emissions estimates for the years 2008 onwards
- Temperature adjusted GHG emissions for the years 2008 onwards
- Provisional estimates of GHG emissions from UK-based international aviation and shipping that are not included in the UK GHG emissions totals.
Only UK GHG emissions are included in the provisional estimates. The Crown Dependencies and Overseas Territories for which estimates are made in the final GHG emissions publication are not included.
Provisional UK GHG emissions estimates
For the provisional estimates, GHG emissions are classified into four categories:
- Energy use GHG emissions derived from energy use data
- Energy use GHG emissions held constant
- Non-energy use GHG emissions derived from projections
- Non-energy use GHG emissions held constant.
The approach taken to estimate annual and quarterly GHG emissions for each of these four categories is summarised in Table 1.
Table 1: Approaches for estimating provisional annual and quarterly UK GHG emissions
| Annual estimates | Quarterly estimates | |
|---|---|---|
| Energy use GHG emissions derived from energy use data | For individual activities/fuel types, year-on-year growth factors are applied to the latest final GHG emissions estimates to derive provisional estimates for the following year. These are based on year-on-year changes in energy use for the closest corresponding sector and fuel type included in the Energy Trends publication. | For individual activities and fuel types, annual GHG emissions are allocated to individual quarters within each year in proportion to quarterly energy statistics, using the same sector and fuel data series used to derive the provisional annual estimate for the latest year. |
| Energy use GHG emissions held constant | For these activities and fuel types, provisional estimates are taken to be the same as the final estimates for the previous year, so no change is assumed between the two years. | For each year in the series these GHG emissions are allocated equally between the four quarters. |
| Non-energy use GHG emissions derived from projections | For each category and gas, a growth factor is applied to the final GHG emissions total for the previous year. This growth factor is based on the year-on-year change in GHG emissions forecast for that category and gas in the latest published EEP. | For each year in the series these GHG emissions are allocated equally between the four quarters. |
| Non-energy use GHG emissions held constant | For these activities and fuel types, provisional estimates are taken to be the same as the final estimates for the previous year, so no change is assumed between the two years. | For each year in the series these GHG emissions are allocated equally between the four quarters. |
Table 2 shows the percentage shares of GHG emissions for each methodological approach by the TES sectors presented in the provisional statistics.
Table 2: Percentage of GHG emissions for each methodological approach in the provisional estimates by TES sector, based on the final 2024 UK GHG emissions
| TES sector | Energy use GHG emissions derived from energy use data | Energy use GHG emissions held constant | Non-energy use GHG emissions derived from projections | Non-energy use GHG emissions held constant |
|---|---|---|---|---|
| Electricity supply | 99% | 1% | 0% | 0% |
| Fuel supply | 77% | 0% | 0% | 23% |
| Domestic transport | 98% | ~0% | 1% | ~0% |
| Buildings and product uses | 92% | 2% | 6% | ~0% |
| Residential buildings | 99% | 1% | 0% | 0% |
| Commercial buildings | 98% | 2% | 0% | 0% |
| Public sector buildings | 98% | 2% | 0% | 0% |
| Other buildings and product uses | 0% | 8% | 92% | ~0% |
| Industry | 82% | 4% | 13% | 1% |
| Agriculture | 12% | ~0% | 87% | 0% |
| Waste | 0% | 0% | 100% | 0% |
| LULUCF | 0% | 0% | 100% | 0% |
| Total GHG emissions | 77% | 1% | 20% | 2% |
Notes: 1. LULUCF is land use, land use change and forestry
2. ~0% indicates where a value is non-zero but is less than 0.5% in magnitude. 0% indicates a zero value.
Table 3 shows the percentage shares of GHG emissions for each methodological approach by gas.
Table 3: Percentage of GHG emissions for each methodological approach in the provisional estimates by gas, based on the final 2024 UK GHG emissions
| Gas | Energy use GHG emissions derived from energy use data | Energy use GHG emissions held constant | Non-energy use GHG emissions derived from projections | Non-energy use GHG emissions held constant |
|---|---|---|---|---|
| Carbon dioxide (CO2) | 98% | 1% | ~0% | 1% |
| Methane (CH4) | 1% | 2% | 89% | 8% |
| Nitrous oxide (N2O) | 7% | 2% | 91% | ~0% |
| Hydrofluorocarbons (HFCs) | 0% | 0% | 100% | 0% |
| Perfluorocarbons (PFCs) | 0% | 0% | 100% | 0% |
| Sulphur hexafluoride (SF6) | 0% | 0% | 100% | 0% |
| Nitrogen trifluoride (NF3) | 0% | 0% | 100% | 0% |
| Total GHG emissions | 77% | 1% | 20% | 2% |
Note: ~0% indicates where a value is non-zero but is less than 0.5% in magnitude. 0% indicates a zero value.
Energy use GHG emissions derived from energy use data
Provisional emissions estimates for the majority of GHG emissions (77% in the 2024 final UK statistics) are based on provisional energy statistics published in Energy Trends on the same day as the provisional GHG emissions estimates. To produce these estimates, it is assumed that the percentage change in GHG emissions between the latest two calendar years is the same as the percentage change in the corresponding energy use over the same period. For example, if the volume of gas used in power stations has reduced by 5% in the energy data, it is assumed that GHG emissions from the use of gas in power stations reduced by 5%.
The GHG emissions are scaled in proportion to energy use data that are categorised into 29 groups based on the GHG emissions categories and fuels shown in Table 4. For each group, a scaling factor is calculated from the energy use statistics. These scaling factors are then applied to the GHG emissions allocated to that group to derive the provisional estimates.
Table 4: GHG emissions categories and fuels for which scaling factors are produced from Energy Trends data to estimate provisional GHG emissions
| GHG Emissions category | Fuel |
|---|---|
| Agriculture | Gas |
| Agriculture | Coal |
| Commercial buildings | Gas |
| Commercial buildings | Coal |
| Energy use | Oil |
| Energy use | Coal |
| Energy use | Gas |
| Industry | Other solid fuels |
| Industry | Coal |
| Industry | Blast furnace gas |
| Industry | Coke oven gas |
| Industry | Gas |
| Marine bunkers | Oil |
| Other | Oil |
| Power stations | Coal |
| Power stations | Non-bio waste |
| Power stations | Gas |
| Public buildings | Gas |
| Public buildings | Coal |
| Residential buildings | Gas |
| Residential buildings | Coal |
| Residential buildings | Oil |
| Residential buildings | Other solid fuels |
| Transport | Gas |
| Transport | Aviation fuel |
| Transport | DERV |
| Transport | Motor spirit |
| Transport | LPG |
| Transport | Gas oil |
| Transport | Coal |
| Transport | Fuel oil |
Energy use GHG emissions held constant
A small number of energy use GHG emissions are held constant from the previous year in the provisional estimates as there is no suitable data available in Energy Trends to scale it by. Whilst only 1% of total energy use GHG emissions (based on the 2024 final UK statistics) are assumed to remain constant in the provisional estimates, this method is particularly prominent for some activities and fuels. For example, all GHG emissions from petrol use in house and garden machinery are assumed to remain constant in the provisional estimates.
Non-energy use GHG emissions derived from projections
Non-energy use GHG emissions make up 22% of total UK GHG emissions (based on the 2024 final UK statistics). The majority of these GHG emissions (91% in the 2024 final UK statistics), in the provisional estimates are derived through use of the projections in the latest EEP publication and contribute 20% of total UK GHG emissions (based on the 2024 final UK statistics). To produce these estimates, it is assumed that the percentage change in GHG emissions between the latest two years is the same as the projected percentage change in the corresponding category and gas over the same period. Projected percentage changes are derived from the reference scenario in the latest EEP publication. For example, if the latest EEP publication projects a 1% fall in methane emissions from agricultural soils for the year that provisional estimates are being produced, it is assumed that methane emissions from agriculture soils have fallen by 1%.
As shown in Table 2, the provisional estimates for the agriculture, waste and LULUCF sectors, as well as for the other buildings and product uses subsector are largely derived from projections. Correspondingly, these sectors are marked as estimates in the published tables to denote that these totals are less reliable than the totals for the other sectors.
Non-energy use GHG emissions held constant
Like the energy use GHG emissions, a small number of non-energy use GHG emissions are held constant from the previous year in the provisional estimates. This is because these non-energy GHG emissions are not separated from energy use GHG emissions in the proxy projections. Overall, these GHG emissions account for 9% of total non-energy related GHG emissions and 2% of total GHG emissions (based on the 2024 final UK statistics). The most significant sources of GHG emissions in this category are fugitive GHG emissions in the fuel supply sector.
The reliability of the provisional GHG emissions estimates
Table 5 compares estimates of year-on-year growth in total GHG emissions from the provisional statistics with those from the final statistics published almost a year later. Overall, the year-on-year percentage change indicated in the provisional statistics has usually been within one percentage point of the change estimated in the final statistics.
Table 5: Percentage differences between provisional and final GHG emissions estimates
| Year | Provisional estimate (total GHG emissions) | Final estimate (total GHG emissions) | Percentage point difference |
|---|---|---|---|
| 2012 | +3.4% | +3.2% | +0.2 |
| 2013 | -1.9% | -2.4% | +0.5 |
| 2014 | -8.4% | -7.7% | -0.7 |
| 2015 | -3.4% | -3.8% | +0.4 |
| 2016 | -6.0% | -5.0% | -1.0 |
| 2017 | -2.6% | -2.7% | +0.1 |
| 2018 | -2.5% | -2.1% | -0.4 |
| 2019 | -3.6% | -2.8% | -0.8 |
| 2020 | -8.9% | -9.5% | +0.6 |
| 2021 | +4.7% | +5.0% | -0.3 |
| 2022 | -2.2% | -3.5% | +1.3 |
| 2023 | -5.4% | -4.9% | -0.5 |
| 2024 | -3.5% | -2.7% | -0.8 |
Temperature adjusted GHG emissions
Energy use GHG emissions are indirectly influenced by external temperatures. During the winter months, GHG emissions are generally higher than in summer months, due to higher demand for fuel for space heating. During a particularly cold winter for example, it is likely that more fuel will be burnt for domestic or commercial use than during an average winter, and therefore GHG emissions will be higher due to the additional fuel consumption.
Temperature adjusted GHG emissions estimates remove the effect of external temperatures. In a particularly cold winter quarter, for example, this will result in temperature adjusted GHG emissions that are lower than actual emissions, reflecting the lower fuel consumption that would have occurred if temperatures had been at average levels. The temperature adjustment makes use of statistics on the number of heating degree days, and how they deviate from the long-term average for the given time of year. This information is published in Energy Trends. Heating degree days measure how often temperatures over the measurement period fell below a base temperature of 15.5C, indicating expected demand for building heating.
Temperature adjustments are only applied to certain activities and fuel types, as not all GHG emissions are affected by external temperatures. The following procedure has been used to determine whether a GHG emissions source should receive a temperature adjustment:
- A simple linear regression is established between the GHG emissions for a given category and fuel type combination and the average heating degree days, from 2002 to 2019 (later years are not currently included because of the behavioural changes seen during the COVID-19 pandemic).
- Coefficients of determination (R2) are calculated, measuring how well the regression line approximates the data points. The R2 takes a value between 0 and 1; the closer it is to 1, the stronger the correlation between the GHG emissions from the given sector and fuel type combination and the number of heating degree days.
- If the coefficient from the regression model is statistically significantly different from zero, and the R2 is sufficiently high, then GHG emissions for that given category and fuel type are temperature adjusted. Otherwise, there is assumed to be no temperature effect, and therefore no adjustment required.
- GHG emissions are adjusted for each category and fuel combination by using the coefficient from the regression model as an estimate of the additional GHG emissions per additional heating degree day. For a given quarter we look at the number of heating degree days by which it deviated from the typical amount of heating required in that quarter of the year (as given by the long-term average for the period 1991-2020).
- Multiplying this deviation by the estimate of the additional GHG emissions per additional heating degree day for the given category and fuel combination gives the estimated temperature effect on GHG emissions. This temperature effect is then removed to give the temperature adjusted GHG emissions.
It should be noted that the temperature adjustment is intended to remove the effect of temperatures varying between years, and it does not adjust for the usual within-year seasonal variation in temperatures. Therefore, quarterly temperature adjusted GHG emissions estimates provide an indication of what GHG emissions would have been if the temperatures that quarter had been in line with the long-term average for that quarter.
The long-term average used in the temperature adjustment is based on the 30-year period 1991-2020. The 30-year period used is usually updated every decade, with the most recent change being made in Energy Trends from June 2022. The period used will affect the absolute level of the temperature adjusted GHG emissions values, but this should not have a significant effect on the trends derived from the adjusted data since all years are adjusted based on the same long-term average. More information about the most recent change can be found in the article about long term mean temperatures in the March 2022 Energy Trends.
Provisional GHG emissions from international aviation and shipping
GHG emissions from international aviation and shipping can be estimated from refuelling from bunkers[footnote 2] at UK airports and ports, whether by UK or non-UK operators. Under the reporting guidelines agreed by the United Nations Framework Convention on Climate Change (UNFCCC), these GHG emissions are not included in UK emissions totals that are submitted to the UNFCCC each year but are reported as memo items in national GHG inventories. They are therefore shown in a separate table from the UK territorial GHG emissions estimates in the final and provisional UK GHG emissions publications.
Provisional estimates of GHG emissions from UK-based international aviation and shipping bunkers were first included in the provisional 2022 UK GHG emission estimates. These estimates are made following the same approach used for energy use GHG emissions derived from energy use in the UK provisional totals, using Energy Trends data. To produce the estimates, it is assumed that the percentage change in emissions between the latest two years is the same as the change in the equivalent energy use between those two years. For GHG emissions from international shipping, the marine bunkers estimates from Energy Trends are used. For GHG emissions from international aviation, estimates for aviation fuels (the large majority of which are used for international aviation) are used. A small proportion of international aviation GHG emissions are related to lubricant use and cannot be estimated through energy statistics. Instead, these GHG emissions are held constant. This approach is consistent with provisional estimates of domestic transport sector GHG emissions from lubricant use.
Quarterly and temperature adjusted estimates are not made for these GHG emissions.
Methodology changes
Methodologies for calculating provisional estimates are periodically updated as our understanding of the factors affecting emissions trends improves and more detailed information becomes available. Methodological changes included in the provisional 2025 GHG emissions estimates improve the apportionment of energy use data for estimation of energy use GHG emissions. Details of the methodology changes are given below.
Non renewable waste use in power stations
Estimates of GHG emissions from the non-biogenic portion of municipal solid waste incineration in power stations have been updated to use provisional energy balance data. Historic data from the final GHG emissions statistics show that emissions from the incineration of municipal solid waste have risen in recent years. However, previously, emissions from this source were assumed to remain constant in the provisional emissions estimates. The method has been updated to use provisional data on electricity generation by fuel type and historical data on fuel efficiency to estimate fuel input of non-biodegradable waste.
Transport fuel use
GHG emissions from transport are now estimated by fuel based on trends in the Energy Trends data.
Previously, Energy Trends fuel use data were aggregated separately by each mode of transport (rail, road or air) to produce separate scaling factors, and the resultant trends applied to estimate GHG emissions for each transport mode. However, estimation of GHG emissions from rail coal use, rail oil use, and waterborne oil use separately relies on trends in small categories in the corresponding energy balance data. Aggregating across transport modes and applying factors based on specific fuel type is deemed to provide more reliable GHG emissions estimates. Residual GHG emissions from the domestic transport sector are mostly held constant in the absence of appropriate Energy Trends proxy data.
This publication is available from: https://www.gov.uk/government/statistics/provisional-uk-greenhouse-gas-emissions-statistics-2025
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The TES sectors are electricity supply, fuel supply, domestic transport, buildings and product uses, industry, agriculture, waste, and land use land use change and forestry (LULUCF). Full sector definitions can be found in the statistical release that this methodology summary accompanies: https://www.gov.uk/government/statistics/provisional-uk-greenhouse-gas-emissions-statistics-2025 ↩
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A large container or compartment that stores fuel for ships or aircraft. ↩