CARBOOCEAN Annual Meeting – Solstrand, Norway 5-9 October 2009 WP17 Highlights: Future Scenarios with coupled carbon-climate models - 5 european modelling groups : IPSL, MPIM, Bern, Bergen, Hadley - Strong link with Euroceans (FP6-NoE) and EPOCA (FP7-LP) - Ocean part of C4MIP (Coupled Carbon Cycle - Climate Model Intercomparison Project : an IGBP/AIMES project, Lead : Pierre Friedlingstein)

CARBOOCEAN Annual Meeting – Solstrand, Norway 5-9 October We developed new complex tools -2- We ran similar long-term experiments (A2 scenario, , and behind) and archived model output in a common database -3- We evaluated our models against observations (WP11) -4- We predicted global-warming induced changes in marine productivity and air-sea CO2 fluxes / anthropogenic carbon storage -5- We assessed the role of other forcing factors: other GHGs, aerosols, ozone hole, dust deposition, … -6- We analysed long-term commitments of carbon 21st century emissions

-1- New Complex Tools … 4 (almost) existing models: IPSL-CM4-LOOP, MPIM-ESM, NCAR-CSM, HadCM3 …1 new coupled climate-carbon model BCM-C: ARPEGE – MICOM – LPJ – HAMOCC5.1 C ant (1994): Model (Tjiputra, Assmann, Bentsen et al. 2009) & Observations (Sabine et al. 2004) Assman et al. Geosci. Model Dev. Discuss 2009 Tjiputra et al. Geosci. Model Dev. Discuss 2009 (  the ocean carbon cycle in a isopycnic ocean model) [mole C / m 2 ]

-2- Experiments & Model Archive In FP6-CARBOCEAN: 5 models : NCAR, MPIM, IPSL, BCCR, Hadley So far in C4MIP, only global CO 2, ocean/land C-fluxes, … as in Friedlingstein et al All 2D, 3D variables, same format, on a web server Model_Name Simulation_Name DIC Alk Fe NO3 Phy, Phy2, … Zoo, Zoo2, … ….. (annual mean from 1860 to 2100, monthly means for , , ) - Will also be used by EPOCA, and used to prepare IPCC-AR5 - New tools to access the data (plot, extraction…)

-3- Evaluation of models (see WP11 talks) - Nutrients & primary productivity (bulk, seasonal cycle, interannual variability) Schneider et al. Biogeosci Air-Sea  pCO2, air-sea carbon fluxes (link with SOCAT) Modern annual-mean CO 2 air-sea Fluxes - Atmospheric pCO 2 Cadule et al. GBC in rev Schneider et al. in prep Roy et al. in prep

-4(a)- Changes in marine productivity (Steinacher et al. Biogeosci. Discuss. 2009) Changes in marine productivity simulated by 3 coupled climate-carbon models in 2100

-4(a)- Changes in marine productivity (Steinacher et al. Biogeosci. Discuss. 2009) Model mean weigthed by skill scores Common features of the models:  Large decrease in the tropics / North Atlantic  Increase in the Southern Ocean

-4(a)- Changes in marine productivity (Steinacher et al. Biogeosci. Discuss Schneider et al. Biogeosci. 2008)) Relationship bewteen bulk PP and sea surface temperature: interannual variability vs long term changes

-4(b)- Changes in air-sea carbon fluxes (Friedlingstein et al. JClim 2006 Roy et al. in prep) All models predict a positive climate carbon feedback (i.e. climate change reduces ocean and land carbon sinks) Simulated atm. CO 2 Additional CO 2 due to CO 2 -Climate feedback +20 ppm +220 ppm

-4(b)- Changes in air-sea carbon fluxes (Friedlingstein et al. JClim 2006 Roy et al. in prep) CARBOOCEAN Models simulate very different feedback gain (g)  CO 2 = 1/(1-g)  CO 2 without feedback NCAR: 4% IPSL: 6% BCCR: 18% MPIM: 20% Hadley: 31% very low to very high… But have a similar effect of climate on ocean carbon uptake… (  o ) From -16 to -24 PgC/°C First order differences are due to the land carbon cycle…

-4(b)- Changes in air-sea carbon fluxes (Friedlingstein et al. JClim 2006 Roy et al. in prep) At the regional level,… consistent features among the different models (for details see T. Roy presentation on Friday) Model mean Impact of climate change on regional carbon uptake (gC/m2/°C) Climate-change reduces the cumulated oceanic CO 2 uptake by: 35–95% in the North Atlantic (North of 36°N) 1–25% % in the Southern Ocean (South of 44°S) But amplify uptake at higher latitudes (arctic ? Antartcic ?)

-5(a)- Impact of other forcing factors - Other Greenhouse gases and aerosols (Cadule et al. GRL 2009) … other GHGs amplify warming and the positive climate-carbon feedback … aerosols cool the climate but increase the gain of the feedback… because of their regional signature on the land carbon cycle (largely mid to high latitudes)

-5(b)- Impact of other forcing factors - Ozone hole (Lenton et al. GRL 2009) …ozone hole amplifies wind stress, increases upwelling of DIC-rich waters and reduces anthropogenic carbon uptake… Air-Sea C Flux (PgC y -1 ) (40°S-90°S) In agreement with inversions (Le Quéré et al. 2007) and  pCO 2 observations (Metzl 2009)

-5(c)- Impact of other forcing factors -Dust deposition changes (Tagliabue et al. Biogeosci Impact of a reduction in dust deposition in 2100… Changes in NPP Changes in air-sea CO2 flux (see also Segschneider talk in WP16)

-6- Long-term commitments Irreversible impacts of 21st century CO 2 emissions on centennial to millennial timescales, Whereas regional perturbations in temperature and precipitation by historical emissions and by non-CO 2 agents are largely reversible within centuries. In the High case, CO 2 remains above 580 ppm and 30% of carbon emissions are still airborne by (Froelicher et al. ClimDyn sub)