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N2O-Climate feedback

N2O-Climate feedback. P.Friedlingstein, L. Bopp, S. Zaehle, P. Cadule and A. Friend IPSL/LSCE. Climate carbon cycle feedback. 11 coupled climate carbon cycle models, same forcing in emissions, two simulations. Positive feedback. Larger climate change.

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N2O-Climate feedback

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  1. N2O-Climate feedback P.Friedlingstein, L. Bopp, S. Zaehle, P. Cadule and A. Friend IPSL/LSCE

  2. Climate carbon cycle feedback 11 coupled climate carbon cycle models, same forcing in emissions, two simulations. Positive feedback Larger climate change

  3. : Anthropogenic but also Natural sources/sinks Radiative forcing Climate - Biogeochemical cycle feedback ?

  4. Feedback estimate • What are the feedbacks between climate and other major radiatively active BGCs • Which ones have to be calculated online Climate-BGC gain

  5. Atmospheric [N2O] * (*) In the following, whenever I say CO2, I mean N2O IPCC, TAR, 2001

  6. N2O Emissions IPCC, TAR, 2001

  7. N2O • What are the potential changes in natural N2O emissions due to climate change

  8. Methodology • Estimate land and ocean N2O emissions • Historical and Future evolution (SRES-A2) • Use of IPSL AOGCM climate fields to drive • ORCHIDEE land BGC model • PISCES ocean BGC model • Estimate atmospheric change due to climate-N2O emission feedback

  9. Experimental design • Land • CO2 forcing only • CO2 and climate change forcing No changes in land-use, fertilizer use, Nitrogen deposition,… Ocean CO2 and climate change forcing

  10. Climate forcing

  11. ORCHIDEE Zaehle et al., 2006 Krinner et al., 2005

  12. Some validation PS Sönke will buy more validation data at any price !

  13. PISCES PO43- Diatoms NH4+ Si Nano-phyto NO3- Fe MicroZoo D.O.M Meso Zoo P.O.M. Small Large N2O Parametrization from Suntharalingham et al., 2002 J_N2O = f(O2 consumption, O2 concentration) Aumont et al., 2003

  14. Ocean validation Observations Nevison et al. 2005 : PISCES Model N2O Flux mgN/m2/yr

  15. Ocean validation Atlantic East Pacific West Pacific Indian

  16. Ocean story Atmospheric pCO2 (ppm) Primary Productivity (GtC/yr) N2O Flux (TgN/yr)

  17. Ocean story 2100 - 1860 Change in O2 concentration (mmol/l) Change in N2O flux (mgN/m2/yr)

  18. Land story N2O Flux (TgN/yr)

  19. Land story Grassland and cropland Grassland and cropland Change in N2O flux (gN/m2/yr) 2100 - 1860 Forests Forests Most of the change occurs in temperate grasslands and croplands

  20. Land story Grassland and cropland Relative change in N2O flux (%) 2100 - 1860 Worldwide increase Forests

  21. Atmospheric N2O Budget Where is the change in atmosphericN2O concentration since PI. is the change in natural emissions since PI is the life-time of N2O in the atmosphere

  22. Atmospheric N2O Budget Emissions ocean 5.5 3.5 1.5 land TgN/yr Atm. Source/Sink 0. -0.2 sink ppb source 10 ppb decrease -0.03 W/m2 Atm. Concentration 275 270 265 ppb

  23. But… key role of N inputs

  24. Conclusions • Climate change alone may induces • decrease of oceanic emissions • increase of continental emissions • Overall effect : negative feedback • Small (10 ppb decrease) relative to future anthropogenic scenarios (+ 200 ppb) • Future continental emissions largely driven by N dep, Nfert. • However …

  25. N2O G-IG changes Positive feedback !!!

  26. Last slide Did we just prove the ice core wrong ?

  27. SRESA2 – IPSLCM2 - NPZD SRESA2 – IPSLCM4 -PISCES

  28. 02 distribution Observations from Levitus (mmol/l) PISCES Model (mmol/l)

  29. Climate forcing

  30. Land story Climate and CO2 Change in N2O flux (gN/m2/yr) 2100 - 1860 CO2 alone Most of the change occurs in temperate grasslands and croplands Climate effect

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