Verification of emissions and sinks through comparison of different methods/models - an overview

1. Verification of emissions and sinks through comparison of different methods/models - an overview After yesterday discussions and presentations I expanded the WHY part and reduced the HOW part G. Seufert Leader of JRC-Project GHG Data Outline: Verification – why? Kyoto and the atmospheric signal The terrestrial carbon cycle = a major unknown Soil carbon under land use change = THE major unknown Verification – how? Examples: Forest C sink in Europe – comparison of different methods Carboeurope: multiple constrains of the European carbon cycle Inverse modelling of CH4-emissions in Europe Conclusions CCC Uncertainty Workshop, Helsinki, Sep2005

2. Verification – why? The challenge of mitigation • The near-term challenge is to achieve the Kyoto targets • The longer-term challenge is to meet the objectives of Article 2 of the UNFCCC, i.e., stabilization of GHG concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system • “To be consistent with good practice as defined in the report, inventories should contain neither over nor underestimates as far as can be judged, and the uncertainties in those estimates should be reduced as far as practicable” (GPG 2000) CCC Uncertainty Workshop, Helsinki, Sep2005

3. Verification – why? In the near-term, independent verification is not really required for fulfilling reporting needs, however • The primary target of the FCCC is the atmosphere (by the way, to protect the atmosphere we need to consider all climate drivers),and Kyoto measures should be visible in the atmospheric signal (one day) • The “practicability” principle of IPCC-type of reporting has the intrinsic problem of potential bias due to partial or non-reporting of potentially relevant sectors (esp. AFOLU) • In the mid-term, lets say within 3-5ys, reliable and well constrained estimates of the European GHG-cycle will be available anyhow by the research community (Carboeurope, Nitroeurope etc.) - at this moment, reporting should be consistent with “latest science” CCC Uncertainty Workshop, Helsinki, Sep2005

4. Verification – why? CCC Uncertainty Workshop, Helsinki, Sep2005

5. Verification – why? Global carbon budget 1980-1999 Fluxes in GtC/year (IPCC Third Assessment Report, Vol 1) 1980s 1990s ------------------------------------------------------------------------------------------------- Atmospheric C accumulation 3.3 ± 0.1 3.2 ± 0.2 = Emissions (fossil, cement) 5.4 ± 0.3 6.4 ± 0.6 + Net ocean-air flux -1.9 ± 0.5 -1.7 ± 0.5 + Net land-air flux -0.2 ± 0.7 -1.4 ± 0.7 ------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------- Net land-air flux - 0.2 ± 0.7 -1.4 ± 0.7 = Land use change emission 1.7 (0.6 to 2.5) Assume 1.6 ± 0.8 + Terrestrial sink (residual !!) -1.9 (-3.8 to 0.3) -3.0 ± 1 (?) ------------------------------------------------------------------------------------------------- Source: Raupach, CSIRO 2002 CCC Uncertainty Workshop, Helsinki, Sep2005

6. Verification – why? Kyoto and the atmospheric signal • Global trend known very accurately • Provides an overallconstraint on the total carbon budget • Interannual variability is of the same order as anthropogenic emissions (terrestrial systems do not sequester efficiently during El-Nino events) • Annual variability is governed by biospheric cycles Source: Tans/NOAA, U.S. CCC Uncertainty Workshop, Helsinki, Sep2005

7. Verification – why? Carbon flux over western Europe as inferred by inverse modelling Continental vs. ocean anomalies in the European carbon balance Kyoto and the atmospheric signal (Carboeurope 2000) CCC Uncertainty Workshop, Helsinki, Sep2005

8. Verification – why? Key fluxes in the terrestrial carbon cycle CCC Uncertainty Workshop, Helsinki, Sep2005

9. Verification – why? Components of the terrestrial carbon cycle PS photosynthesis CWD Course Woody Products Ra autotrophic respiration Rh heterotrophic respiration SOM Soil Organic Matter CCC Uncertainty Workshop, Helsinki, Sep2005

10. Verification – why? Carbon stocks in global ecosystems Carbon stocks in [kg m-2 ] Based on IPCC LULUCF-Report 2002 CCC Uncertainty Workshop, Helsinki, Sep2005

11. Verification – why? Land-use change and soil erosion in Germany (without Alps) (from IGBP 2003) arable land grassland, fallow land woodland CCC Uncertainty Workshop, Helsinki, Sep2005

12. Verification – why? Ecosystems – Country C budget • Land use matters in many countries compared to fossil emissions • Forests are a major and grassland a minor sink • Croplands are major source • Trade confounds atmospheric signal • Peatlands are small, but important in some countries from Janssens et al. 2004 CCC Uncertainty Workshop, Helsinki, Sep2005

13. Verification – why? Reporting of CO2 Emissions and Removals from Soils by EU 15 CCC Uncertainty Workshop, Helsinki, Sep2005

14. Verification – why? Conclusions: • The terrestrial carbon cycle is a major climate driver • At the same time it is a major unknown (e.g., high interannual variability but no annual data, quantification of ecological cycles vs. one-way emission from fossil sources, simple scaling from timber volume inventories does not consider ecological cycles) • Major part of terrestrial carbon is stored in soils • Major part of soil carbon was lost to the atmosphere during land use history (could partly be recovered through proper PAMs in the AFOLU-sector ) • LULUCF is potentially relevant for some countries but has not been taken serious in previous reporting (no uncertainty estimates, no projections, only partial reporting) • This may have relevant implications for some countries with regard to adjustment decisions and net-net/gross-net accounting under KP CCC Uncertainty Workshop, Helsinki, Sep2005

15. Verification – how? Compiled by H.Dolman, Carboeurope CCC Uncertainty Workshop, Helsinki, Sep2005

16. Verification – how? Example 1: JRC project GHG Data with its objective to support the EC GHG Inventory System Focus on: largest contributors to the uncertainty, i.e. - terrestrial carbon sinks - CH4 & N2O sources and sinks in agricultural activities (soil, animals) Approach: - harmonize and improve MS methodologies - develop EU wide methodologies (with research community) Users: POLICY IMPLEMENTATION - DG ENV Monitoring Mechanism Committee - IPCC Good Practice Guidance - Member States __________________________ Part 1) Conceptual Framework CCC Uncertainty Workshop, Helsinki, Sep2005

17. Activity B CCC Uncertainty Workshop, Helsinki, Sep2005

18. Verification – how? Forest Carbon Budget Process Modelling and Information System Meteorological data Soil Atmospheric CO2 Growth Respiration Maintenance Respiration Autotropic respiration PSN Vegetation Allocation to new growth Plant Litter N uptake Soil organic matter Soil mineral N C Atmospheric N N CCC Uncertainty Workshop, Helsinki, Sep2005

19. Verification – how? Example 2: Carboeurope multiple constraint approach CCC Uncertainty Workshop, Helsinki, Sep2005

20. Verification – how? CarboEurope-IP - Overall objective: Understand and quantify the terrestrial carbon balance of Europe and associated uncertainties at local, regional and continental scale. Target: • Daily-monthly at “Eurogrid” resolution (10-100km x 10-100km) • Continental annual uncertainty 10% CCC Uncertainty Workshop, Helsinki, Sep2005

21. Verification – how? Workshop “Inverse modelling for potential verification of national and EU bottom-up GHG inventories " Example 3: Inverse modelling under the mandate of Monitoring Mechanism Committee 23-24 October 2003 JRC Ispra Environment CCC Uncertainty Workshop, Helsinki, Sep2005

22. Verification – how? Inverse modelling of CH4 emissions in Europe TM5 model – atmospheric zoom model • offline atmospheric transport model • meteo from ECMWF • global simulation 6o x 4o • zooming 1o x 1o (Europe, …) • http://www.phys.uu.nl/~tm5/ CCC Uncertainty Workshop, Helsinki, Sep2005

23. Comparison a priori / a posteriori emissions Example: Inverse modelling CCC Uncertainty Workshop, Helsinki, Sep2005