Scottish Greenhouse Gas Statistics 2024

All of the information contained in Annex A is reported on the basis of the most up to date available greenhouse gas inventory methods, i.e. the 1990 – 2024 inventory.

Section 34A of the Climate Change (Scotland) Act 2009 (“the 2009 Act”) requires that this report contains the information specified in subsection 34(1) of the 2009 Act.

The following paragraphs provide the information specified in section 34(1)(a) in relation to net Scottish emissions of greenhouse gases.

(i) The baseline

The Baseline period uses a 1995 base-year for F-Gas emissions, and 1990 for all other greenhouse gases. In the 1990-2024 inventory the baseline amount of emissions was 78.7 MtCO2e.

(ii) The aggregate amount of net Scottish emissions of greenhouse gases for the year covered by the report.

On the basis of the 1990-2024 inventory, net Scottish emissions in 2024 were 39.0 MtCO2e.

(iii) The percentage by which the aggregate amount of net Scottish emissions of greenhouse gases for the year covered by the report is lower than the baseline.

On the basis of the 1990-2024 inventory, net Scottish emissions in 2024 were 50.5 % lower than the baseline.

(iv) The percentage by which the aggregate amount of net Scottish emissions of greenhouse gases for the year covered by the report is lower or higher than the equivalent amount for the immediately preceding year.

On the basis of the 1990-2024 inventory, net Scottish emissions in 2024 were 1.0% lower than in 2023.

(v) The methods used to determine the aggregate amount of net Scottish emissions of greenhouse gases, together with details of any changes to those methods.

The aggregate amount of net Scottish emissions set out above has been determined from regional disaggregation of the UK Greenhouse Gas Inventory. Full details of the methodology used in the UK Inventory, together with further breakdowns, are provided in the National Inventory Report submitted annually by the UK Government to the United Nations Framework Convention on Climate Change (UNFCCC).  This latest release includes the following revisions to previous calculations:

• Agriculture
  • There are updates to dairy cattle emissions due to a re-parameterisation of the dairy cattle growth curve using slaughter-weight data resulting in an increase in liveweight of all dairy animals and enteric CH4 emissions. 
  • For sheep, there was a downward adjustment in the assumed metabolisable energy density of grazed grass, to better match survey evidence, that directly resulted in an increase in total dry matter intake to meet the energy requirements of an animal.
  • Manure management estimates were also impacted by the re-parameterisation of the dairy cattle growth curve using slaughter-weight data resulting in an increase in liveweight of all dairy animals and therefore changes to the volatile solids (VS) and nitrogen excretion.  
  • Manure management estimates were also impacted by the updated the metabolisable energy content of grass in preferential grazing areas resulting in an increase in nitrogen excretion.  
  • Small additional manure management specific changes arise from an update to the percentage of manure diverted to anaerobic digestion, with minor revisions from around 1991 onwards, increasing toward the end of the time series.
• Buildings and product uses
  • Updates were made to the mapping grids for oil in Commercial/Institutional stationary fuel use and Residential stationary fuel use from 2005. 
  • Note there are also UK level revisions due to splitting the natural gas data from DUKES based to quantity of biogas injected into the grid, which results in minor sector specific changes in emissions from natural gas.

• Transport
  • There are large shipping recalculations at the DG and UK level due to updating the shipping model to use 2019 as Base Year (instead of 2014) as part of implementing the Greenhouse Gas Inventory Improvement Project shipping improvement. This includes the following updates:
  • There are substantive reductions to fuel use for Domestic Shipping due to the transition from a ‘fuel used’ approach to a ‘fuel sold’ approach (normalising modelled shipping fuel use to national energy statistics from DUKES).
  • Assumptions for fuel consumption and emissions at berth have been reviewed and revised emission factors and assumptions from the Department for Transport's (DfT) Maritime Emissions Model (MEM) have been incorporated as part of the model
• LULUCF
  • Updated new planting estimates for 2023 provisional data.  
  • Updated wood production estimates for 2023 provisional figures. 
  • Update to the total woodland area by correcting the area of unmapped woodland for Great Britain. The total ’unmapped NFI’ area found in the 2017 Forestry Commission Tree Cover Outside Woodland in Great Britain report was previously added to small woodland area. This ‘unmapped NFI’ data contains both ‘extra’ woodland area that was missed in previous surveys and ‘new’ woodland planted between 2014 and 2015.
  • Improve the species and Yield Class (growth rate) distribution for recent (post-2011) afforestation to better reflect recent planting practices. 
  • Wood Product Trade Statistics: 
    • Updated woodfuel supply estimates for 2022-2023. 
    • Updated sawmill consumption by country estimates from 1994-2022 due to error correction. 
    • Updated roundwood delivery estimates for 2023 provisional figures. 
    • Updated roundwood fencing estimates from 2006-2014 due to error correction in dataset received from Forestry Statistics. 
    • Updates to deforestation estimates for 2015-2023 based on revised figures on rewetted areas received from Peatland ACTION. 
    • Updates to CARBINE modelling: 
    • Closer match to total wood production across the time series. 
    • Include the transfer of carbon from branches on dead trees into the soil. 
  • Peatlands.  The majority of the change arises from the update to the CARBINE model to include the transfer of carbon from branches on dead trees into the soil which impacts both mineral (reported in Forestry) and organic (reported in Peatland) soil. The remaining minor changes arise from two activity data changes. The first is a recalculation of the hydrological buffer/footprint applied by Peatland Action to the length of ditches blocked, which has reduced from 50m (biodiversity and hydrological footprint) to 30m (hydrological footprint), to align with Peatland Code methodology, which slightly reduced the areas of restoration. Secondly, additional hectares of restoration have been added to the Scotland time series. 

• Waste
  • Recalculations to Managed anaerobic waste disposal sites are driven by an update to the landfill model to use gross GDP data to approximate solid waste disposal volumes where actual activity data is unavailable. Importantly, historic data on solid waste disposal at landfill sites is uncertain and unavailable before 1997. Previously, solid waste disposal volumes from 1990 to 1996 were extrapolated from 1997 data using household and employment statistics. However, an external review of this method highlighted that it is inconsistent with the IPCC Guidelines for National Greenhouse Gas Inventories. To improve consistency with IPCC guidelines, the landfill model has been updated to use GDP data as a proxy for solid waste disposal volumes. This change is exclusive to the waste sector and leads to a large decrease in landfill emissions estimates over the early portion of the historic time series. 
  • There are recalculations (Domestic wastewater treatment and discharge) due to the implementation of the new municipal wastewater model to improve consistency with IPCC guidelines and capture UK-specific wastewater treatment practices:
  • Increase to N2O emissions in all years due to estimating emissions from aerobic treatment, which has a much higher emission factor than the emission factor for N discharged to receiving waters and represents an almost tripling in N2O emissions estimates from this sector;
  • Decrease to CH4 emissions in the 1990s due to using a lower value for the maximum CH4 producing capacity;
  • Increase to CH4 emissions after ~2000 due to estimating emissions associated with Biological Oxygen Demand (BOD) remaining in effluent discharged to receiving waters; 
  • Increase to CH4 emissions in all years, but more in later years than the 1990s due to the 2019 methodology combined with UK-specific CH4 capture rates resulting in higher emissions than the previous Carbon Accounting Workbook (CAW)-based method;
  • Increase to CH4 emissions in all years due to introducing an estimate of emissions from sewers; and
  • New estimates of CO2 emissions from liming and decomposition of materials with fossil Carbon content where previously no estimate was made.
  • Updated municipal wastewater treatment mapping grid, based on the data provided into the model, that has resulted in specific recalculations across the time series; the previous driver utilised population as a proxy for distributing municipal wastewater emissions.
  • There are recalculations to 5D2 (Industrial wastewater treatment and discharge) due to:
    • Estimates for CH4 and N2O emissions from the discharge of industrial wastewater being included in this submission where previously emissions were not estimated. Inclusion of this emissions source is now justified through its addition to the common reporting table (CRT) format used to comply with international reporting commitments.
    • Estimates for CH4 and N2O emissions from industrial wastewater treatment for 5D2 being revised in this submission. This is primarily due to the adjustment to the activity data (e.g. the industrial production estimates for various products allocated to industry) revision to the approach to splicing and gap-filling of various datasets used.

Section 34(1)(b) of the 2009 Act requires that this report contain the following information  In relation to the net Scottish emissions account.

(i) Its amount for the year covered by the report.

In 2024, the net Scottish emissions account was  39.0 MtCO2e.

(ii) The percentage by which the account for the year covered by the report is lower than the baseline.

On the basis of the 1990-2024 inventory, the net Scottish emissions account in 2024 was 50.5 % lower than the baseline.

 (iii) The percentage by which the account for the year covered by the report is lower or higher than the equivalent account for the immediately preceding year.

On the basis of the 1990-2024 inventory, the net Scottish emissions account in 2024 was 1.0 % lower than in 2023.

 (iv) The percentage of any reduction in the account for the year covered by the report, relative to the equivalent account for the immediately preceding year, which is accounted for by reductions in net Scottish emissions of greenhouse gases.

All (100%) of the reduction in the net Scottish emissions account between 2023 and 2024 was accounted for by changes in net Scottish emissions of greenhouse gases.

Section 34(1)(c) requires that this report provides The total amount of carbon units that were—

(i) Credited to or debited from the net Scottish emissions account for the year covered by the report.

No carbon units were credited or debited to the net Scottish emissions account for 2024.

(ii) Purchased by the Scottish Ministers in the year covered by the report.

No carbon units were purchased by Scottish Ministers in 2024.

(iii) Held by the Scottish Ministers immediately after the end of the year covered by the report and which remained available to offset greenhouse gas emissions for other target years.

No carbon units were held by Scottish Ministers immediately after the end of 2024.

Section 34(1)(d) of the 2009 Act requires that for each target year preceding the year covered by this report states the following.

(i) The aggregate amount of net Scottish emissions of greenhouse gases.

(ii) the amount of the net Scottish emissions account *

* The figures set out here for the net Scottish emissions account for the years 2010 to 2017 are consistent with the approach used in previous statutory annual target reports and are on the basis of Scottish emissions adjusted for the operation of the EU Emissions Trading System (EU ETS). The Climate Change (Emissions Reduction Targets) (Scotland) Act 2019 has subsequently altered the emissions accounting basis for assessing progress to targets from 2018 onwards, to remove that adjustment. As such, these earlier figures are not directly comparable to those in other columns of the table or other sections of the report.

(e) the fair and safe Scottish emissions budget, and the aggregate amount of net Scottish emissions of greenhouse gases for the period from 2010 to the end of the year covered by the report.

The fair and safe Scottish emissions budget for emissions over the period 2010 to 2050 is 1,129 MtCO₂e. The total amount of net Scottish emissions of greenhouse gases over the period from 2010 to 2024 is 722.5 MtCO2e.

 Section 34A(6) of the 2009 Act requires that, if the methods used to determine net Scottish emissions of greenhouse gases change and that change is such as to require adjustment of an amount for an earlier target year, the report must  —

(6)

(a) specify the adjustment required and state the adjusted amount, and  (b) explain why the adjustment is required.

The latest greenhouse gas inventory (1990-2024) contains some relatively significant revisions to previous estimates of emissions, primarily affecting shipping and waste emissions for earlier years in the time-series.  In both cases, these revisions have been implemented to enhance consistency with IPCC guidance and international best practice.  These revisions are listed in more detail in section 34 (v).

The combined impact of these changes has resulted in the previously published value for emissions in 2023 being decreased by 0.2 MtCO2e to the revised level of 39.4 MtCO2e.