Dr Amanda Thomson, NERC Centre for Ecology & Hydrology

1. Dr Amanda Thomson, NERC Centre for Ecology & Hydrology National Environmental Statistics Advisory Committee Autumn Meeting – Wednesday 28th November 2012 An introduction to the LULUCF sector in the national Greenhouse Gas Inventory

2. Presentation overview An introduction to greenhouse gas (GHG) inventories The Land Use, Land Use Change and Forestry (LULUCF) sector Calculating net emissions • Forestry • Land Use Change • Land Management Related research and developments Questions

3. Why do we need them? Because we need to measure progress towards national and international GHG reduction targets An introduction to greenhouse gas inventories

4. National GHG inventories Energy Land Use, Land Use Change and Forestry What is an inventory? • Not just a list! • Detailed year-on-year assessment of national GHG emissions • Made up of a complex linked database & models • Follows international protocols & audit to allow inter-national comparison Industrial Processes NATIONAL GHG INVENTORY Solvents Agriculture Waste

5. Annual Publications • International and national submissions: • UN Framework Convention on Climate Change • UK and Devolved Administration climate change targets

6. The Land Use, Land Use Change and Forestry (LULUCF) sector

7. What is LULUCF ? Land Use, Land Use Change and Forestry Covers anthropogenic GHG emissions and uptake by vegetation and soil • Changes in carbon stocks (carbon dioxide (CO2)emissions by sources and removals by sinks) • Emissions of GHGs by sources: CO2, methane (CH4) , nitrous oxide (N2O) Only sector that can have a potential carbon sink Inventory consists of annually-updated values for each year between 1990 and current year (2010)

8. LAND USE CATEGORIES All land in a country must be assigned to one of these categories Land use areas are compiled from multiple sources: • Forestry Commission • Countryside Survey • Agricultural statistics • Other government statistics

9. Scottish net LULUCF emissions 1990-2010

10. CEH and LULUCF CEH has led the compilation of LULUCF inventories since the mid-1990s Each year we produce: • Annual inventories for the UK, England, Scotland, Wales and Northern Ireland and the UK’s Overseas Territories and Crown Dependencies • Projections of emission scenarios to 2050 • Breakdowns of the latest inventory numbers by Local Authority • Advice on the LULUCF sector and science for policy makers and international negotiations

11. Reporting Schedule National inventory report (2 chapters and annex) Maps of LULUCF emissions and report Devolved administration GHG inventory report Inventory data for UK, OT/CDs, completed CRF tables Devolved administration LULUCF report and numbers Reporting deadlines Projections of LULUCF emissions to 2050 UNFCCC submission with UK and OT/CD numbers DECC emission statistics published Data submissions EU submission with UK numbers UNFCCC Expert Review EC consistency report checks UNFCCC synthesis and assessment report review Reviews UK internal review (numbers and report text)

12. Methodology overview Have to follow Good Practice Guidance laid down by Intergovernmental Panel on Climate Change (IPCC) • Transparent, consistent, comparable and accurate IPCC provide default methods and emission factors (GHG emitted per unit area) but it is good practice to develop country-specific methods and data

13. Carbon stock changes in vegetation and soils and greenhouse gas emissions from forest management Calculating emissions: Forestry

14. Forest activities producing GHG emissions

15. forest Management: Planting Age profile of woodland in Scotland (adapted from 1995-99 National Inventory of Woodland and Trees) Forest area inventories occur at irregular intervals in the UK UK woodland area at 31 March 2011: 3.1 Mha (56% conifers) (2010 NFI) vs. 2.9 Mha estimated from 1995-99 NIWT adjusted for new planting c. 68% of UK woodland area have been planted since 1950 Forestry Commission production planning uses area and Yield Class models rather than frequent inventory Annual planting data is comprehensive (available since 1921)

16. forest Management Activity data Area of new forest planting provided annually by the Forestry Commission (split by conifer/broadleaf and FC/privately-managed) All broadleaf planting assumed to be on mineral soils Conifer planting split between mineral and organic soils on country-specific basis Adjusted for deforestation losses Split between Forests established prior to 1920 assumed to have zero net carbon flux Forests established 1921- fluxes modelled with C-Flow C-Flow model calculates the net change in pools of carbon in standing trees, litter and soil in conifer and broadleaf forests and in products

17. Forest Carbon flows in the C-Flow model Atmospheric CO2 Photosynthesis (NPP) (from volume growth curve & expansion factors) Product decay Stem thinning Wood products Woody biomass Non-woody biomass and harvesting Natural mortality Thinnings Harvest debris Woody litter Non-woody litter Woody litter decay Non-woody litter decay Transfer of residues to soil Soil organic matter Soil decomposition

18. C-Flow post-model processing Allocation of Land converted to Forest between Cropland/Grassland/Settlements based on proportional allocation in Countryside Survey data Adjustment of Forest carbon stock changes for deforestation using original implied carbon stock changes (Mg C/ha) and adjusted areas

19. Harvested Wood Products Timber is added to the harvested wood products pool from Harvesting and thinning under standard forest management Timber produced from deforestation 5% of living biomass transferred to litter and soil pools at felling Residence times (time of 95% of C to be lost) of wood products depend on type and origin of products and exponential decay constants Thinnings= 5 years; Softwood products: 59 years Hardwood products: 92 years New IPCC method will subdivide wood products pool by end product category, e.g. wood panels

20. ForestRY Uncertainties 5A Forest Land – uncertainty of 22% Main sources of uncertainty: Afforestation model parameters Afforestation input data Forest soil carbon model choice Afforestation model choice Afforestation model choice and parameters: move to the Forestry Commission CARBINE model for better representation of UK forest management Afforestation input data : these come from operational systems- have no associated statistical uncertainty- NFI will provide checks on reliability in future Forest soil carbon model choice- work is planned on this for 2013-14 Time consistency is good for forest activity data

21. Carbon stock changes in vegetation and soils and greenhouse gas emissions from land use change Calculating emissions: Land Use Change

22. Land use change activities producing ghg emissions

23. land use change • Land use change affects: • Biomass (short term) • Soil carbon (long term changes) • Need to know land use changes between different land use types • Current approach based on Countryside Survey data

24. The UK Countryside Survey sample squares

25. land use change activity data 2 • Countryside Survey data is not used for estimates of forest area • Different definition of forest cover: 25% canopy cover at survey date vs. Forestry Commission 20% cover or potential to achieve it • Inconsistent definitions between surveys • Forestry Commission statistics give complete coverage of new planting • Land use change to Forest is calculated by the C-Flow model • Activity data for land use change from forest is compiled from other data sources • LUC matrix/soil carbon model calculations are modified to take account of these differences • Limitations of Countryside Survey dataset: • Inflexible • Relatively small sample (879 squares for UK in 2007) • Discrepancy between land cover and land use • Multiple land use change over short time scales, e.g. through crop/grass rotations are not captured well

26. land use change soil carbon model • UK has extensive data on soil type and soil property -> soil carbon density database • Rates of change of soil carbon as a result of land use change are assumed to depend upon location and type of land use transition • Method follows the IPCC GPG LULUCF but takes account of long term soil carbon dynamics • Soil carbon changes due to LUC continue to be reported for many decades

27. forest conversion to other land use: deforestation • Affects carbon stock changes, N2O emissions from forest land converted to cropland and controlled biomass burning • Area of forest conversion used to adjust areas Forest Land • 60% of biomass converted to HWP- reported as Loss in above-ground biomass, and 40% is burnt on-site • Carbon stock changes in soils- calculated by the land use change/soil carbon model • HWP is calculated using look-up tables from C-Flow model • Biomass burning uses default methodology and GHG emission ratios

28. Deforestation Activity data Source data for Forest-grassland conversion Unconditional felling licences from Forestry Commission England: 2000-2010 Scotland: 1999-2010 Wales: 1996-2010 Use relative rates of woodland conversion from Countryside Survey 1990-1998 and 1999-2007 to gap-fill for: 1990s Conversion to Settlement (Scotland and Wales)

29. Carbon stock changes in vegetation and soils and greenhouse gas emissions from land management Calculating emissions: Land Management

30. Land management activities producing ghg emissions

31. Peat extraction • Uses extraction site locations (from published Directory of Mines and Quarries) and Google Earth to measure areas of active extraction • Sites categorised by production of peat for horticultural use (nutrient-poor) or fuel use (nutrient-rich) • Horticultural peat extractor sales published annually • Annual production and emissions are highly variable because extraction is weather dependent

32. Uncertaintiesfor land management and land use change • Uncertainty analysis undertaken 2011-2012 • Looked at uncertainty in : input data, parameters, structural/model choice • Monte Carlo simulations run to propagate input and parameter uncertainty • Used standard deviation in output distributions as measure of uncertainty • Areas undergoing land use change are the biggest uncertainty

33. Uncertaintiesfor land management and land use change • Recommendations for reducing uncertainty from areas of land use change: • Other sources of land use data should be incorporated into the inventory, so as to constrain the largest source of uncertainty. • Move to a vector-based representation of land use data • Use a numerical optimisation procedure to reconcile differences between data sets. • Good time series consistency for all key datasets

34. Inventory development is driven by the need to reduce key uncertainties Related research and development

35. Planned improvements Improvements in 1990-2011 inventory New data on wildfires (forests and moorland) N2O emissions from drainage in forests Improvements to forestry data and modelling Revision of Forest Land area when National Forest Inventory data is finalised (awaiting statistics on woodland loss) Assessment of carbon stock changes in pre-1921 woodland Improvements to modelling of soils and roots Replacement of C-Flow carbon accounting model with FC CARBINE model Data assimilation to improve land use change matrices/vectors New research on the impact of cropland and grassland management on soil carbon

36. New research projectImpact of cropland and grassland management on soil carbon (Defra SP1113) • The first robust UK assessment • 2012-14 (7 partner organisations) • Key questions: • Which management practices gain or lose the most soil carbon? • How does this vary across the UK in space/time? • What is the potential of land management to reduce GHG emissions now and in the future?

37. Thank you for listening. Questions?