1. CarboEurope: The Big Research Lines Annette Freibauer Ivan Janssens

2. Contents The European C balance Trends and variability Processes Verification of emission reductions Open issues and future directions

3. The European C balance What is the carbon balance of the European continent and its geographical pattern, and how does it change over time? Janssens et al. 2003

4. The European C balance Achievements –Unpreceding density and consistency of ecosystem and atmospheric observations and available data on land surface properties –Improved top-down and bottom-up methods –Data analysis and model intercomparison for interannual variability –Regional experiment –Ongoing analysis of atmospheric trends –Updated sectorial European C balance in progress BUT –Missing regions –Missing „small“ and lateral C fluxes –Long lag for use by modelers –No multiple species constraints –Mismatch in scale between observations, models, methods –Mainly 2003 heat/drought wave: NEP patterns similar for different reasons –Great data waiting for deeper analysis –Full radiative forcing –Realism in models: management

5. C balance: variability Heimann et al., GHG Book, in press

6. Processes What are the controlling mechanisms of carbon cycling in European ecosystems? How do external parameters such as climate change and variability, and changing land management affect the European carbon balance? Ciais et al. 2005 Magnani et al. 2007

7. Processes Achievements –Effects of climate extremes on site level GPP, NEP, RECO –Generalized GPP-NPP-NEP relations –N deposition: enhanced NEP in forests –Importance of advection Regional atmosphere Eddy sites (+ footprint correction) –Failure of the „dead soil paradigm“ BUT –Ecosystem models inconsistent –Forests only –Future trends in NPP in response to climate extremes –Reduced NEP in wetlands? Effects of N saturation? –More constraints and quality checks for long-term data –Vulnerability of soil C –Too low attention to land use and management

8. Verification of emission reductions Can the effective CO 2 reduction in the atmosphere in response to fossil fuel emission reduction and enhanced carbon sequestration on land be detected in the context of the Kyoto commitments of Europe? Levin and Rödenbeck 2007

9. Verification of emission reductions Achievements Changes of about 7-26% in fossil fuel emissions in respective catchment areas could be detected with confidence by high- precision atmospheric 14 CO 2 measurements when comparing 5-year averages, if these inter- annual variations were taken into account. Levin and Rödenbeck 2007 But Improved spatio- temporally explicit fossil fuel maps More 14 CO 2 measurements needed Kyoto targets are too small in many regions

10. Challenges for 2008 Updated European budget by models Atmospheric and ecosystem trends Data analysis & synthesis towards –Land use and management Integration of forest inventories –Attribution of trends to processes –Quantitative systematic uncertainties across scales Regional CCDAS

11. Future directions Stormy times ahead!

12. Long-term goals Improved prognostic capacity of the global and regional C balance –Reduced uncertainty by long-term observatories methodological advances –Realism of processes, thresholds and trends –Link between land – atmosphere – ocean –Coupled major element cycles Climate protective land management –How to manage the vulnerable land C pools –Optimal adaptation and mitigation by land use in the context of multiple pressures

13. Possible future CarboEurope Goal: Attribution of regional changes in carbon budget from 1990 to 2012 to human and natural drivers: Quantify the annual to decadal trends carbon budget of European regions from 1990 to 2012 driven by climate trends, fossil fuel emissions, land use and land use change and quantify the associated effects on the surface energy and water balance.

14. Challenges Maintain Leadership Integration Consistency Continuity Commitment Bridge Globe Nitrogen Erosion, freshwater Ocean Stay on board!

15. Possible future CarboEurope By: Core set of long-term observations Observations and models expanded to –Anthropogenic CO 2, CO and CH 4 –undersampled regions –full radiative forcing –lateral C fluxes More realism in land use and management in models and data assimilation systems New instrumentation and methods need to developed to improve the spatial and temporal match between observations and models. Focus on European continent as a whole and on critical European regions with rapid socio-economic and climate-driven changes.

16. Challenges for this week Review of progress and start further synthesis: –What was achieved? –Where are the gaps? –How to address them? Quantifying and understanding the regional terrestrial carbon balance: GPP, NPP, NEP, NBP –European flux maps & budget (incl. temporal variation) –uncertainties: where are the major uncertainties, how to address them –update on upscaling / downscaling methods –data assimilation Attributing trends and variability in the carbon balance to human and natural (climate) factors: Land use and land use change –The legacy of land use and disturbance: how large and long is it? –How much do land use history and management affect the present terrestrial C balance? –Can climate variability and human trends be separated?

17. Open issues and future directions Update of the European C budget –Missing regions: Eastern Europe –Missing fluxes: Spatio-temporally expicit anthropogenic fluxes of CO 2, CH4, CO, VOC „Small ecosystem C fluxes“ (DOC/DIC; VOC, CH4) Lateral C displacement (harvest, leaching, erosion, rivers,...) –Full use of multiple atmospheric constraints –Data assimilation of remote sensing and in situ observations –Nutrient and water constraints Attribution of trends and variability, process understanding –Full radiative forcing –Land management –Vulnerability of soil C –Future trends in NPP in response to climate extremes Verification –Regional fossil fuel emission reductions –Knowledge and tools for full C accounting of land management