Coordinated by: CARBOOCEAN Integrated Project Contract No (GOCE) Global Change and Ecosystems The big scientific questions – new answers and new challenges Core Theme 5 Future scenarios for marine carbon sources and sinks

The questions and challenges: What is going to happen? What are the uncertainties associated? What if deliberate ocean storage comes back as a mitigation option? Integration of carbon observations into an integrated prognostic modelling frame-work: Operational goal: Best possible science-based projections of ocean carbon sink behaviour for scenarios of future energy use and climatic change will be developed. The initial conditions for the scenarios will be compiled through a combination of observational data and modelling. The models will include formulations of new biogeochemical feedback mechanisms. Data collection and model simulations will be coordinated in particular with marine carbon cycle research activities in the US Delivery: Assessment of future marine CO2 uptake kinetics based on models and data.

What is going to happen?

MPI IPSL Sabine et al Anthropogenic DIC WP17 Bopp, Segschneider

ECHAM5 T63L31 JSBACH MPI-OM PE 610 GtC CO2 emissions 2200 GtC HAMOCC5 NPZD Interface albedo photosynthesis, stomatal conductance phenology carbon pools 1740 GtC soil, hydrological and energy balance The MPI Climate – Carbon Cycle Model GtC Courtesy Thomas Raddatz Atmosphere Ocean Land- biosphere WP17 Segschneider

Earth System Model forcing WP17 Segschneider et al.

WP17 Segschneider, MPI model system

coex90 WP17 Segschneider, MPI model system

Phosphate AtlanticPacific Simulated Annual Mean Year 100 [  mol / l ] Observed WOA05 [  mol / kg ] Model development, isopycnal HAMOCC/ MICOM, WP17, Karen Assmann, Bergen:

pre-industrial (PI) climate, CO 2 =280ppm pre-industrial (PI) climate, CO 2 =316->367ppm (XX) climate, CO 2 =280ppm (XX) climate, CO 2 =316->367ppm Net ecosystem production for different LPJ runs (blue CO 2 uptake, red CO 2 release) Model development, terrestrial C cycle and Bergen Climate Model, WP17, Kristof Sturm:

Hovmueller diagram showing the global zonal mean evolution of the surface aragonite saturation state at different latitudes. The saturation horizon (thick line) reaches the surface by the year 2050 at high northern latitudes. After the year 2070, high latitude regions will become largely undersaturated. WP17, Joos et al., Bern

Changes in the volume of water with an aragonite saturation state below 1 (undersaturation, green) and between 1 and 2 (red), 2 and 3 (blue), 3 and 4 (grey), and above 4 (orange). By 2100, the saturation is always smaller than 3.

Heinze et al., 2006, GBC Change in 230 Th, equatorial Pacific Change in 230Th, equat. Pacific, after CaCO3 export 1/3, Heinze et al., 2006, GBC

What are the uncertainties associated (with the predictions)?

Friedlingstein et al., 2006, Journal of Climate, C4MIP Why Earth system modelling? year

NCAR WP17

Sabine et al., 2004 Model results CARBOOCEAN C ant water column inventory

Feb 1995 Takahshi, LDEO webside Aug 1995 Model results CARBOOCEAN Feb 1995 surface ocean pCO 2 Aug 1995

What if deliberate ocean storage comes back as a mitigation option? (an option we do not really like…)

SPIEGEL ONLINE Dezember 2006, 10:13 URL: CO2-SPEICHER IM MEER Teures Seegrab für den Klimakiller* Von Gerd F. Michelis Um Kohlendioxid von der Atmosphäre fernzuhalten, kann man es einfach im Meer eingelagern - diese Idee wird inzwischen auch in Deutschland ernsthaft geprüft. Experten warnen vor den Risiken. Und vor immensen Kosten für die Stromkunden. Expensive ”Davy Jones's locker” for the climate killer

Experiments on CO 2 -droplet rise velocity Midwater release option adresses release, rise, and dissolution of liquid CO 2 at intermediate (<2800m) water depth CO 2 droplets dissolve in the process of rising upward due to buoyancy during ascend, hydrate forms at CO 2 -seawater interface, retarding dissolution understanding dissolution characterisitcs of CO 2 droplets in the flow field is therefore essential for assessing the depths distribution of the released CO 2, near injection pH fields etc. First adresses experimentally:Rise Velocity WP18 Rehder, Gust, Allendal et al.

Experimental setup for rise velocities Release of single droplets within pressure lab with free control of p, T measurment of rise velocity by passing through 2 horizons of known distance by cameras in pressure housing size determination by monitoring droplet after focussing its pathway through a funnel to avoid parallax WP18 Rehder, Gust, Allendal et al.

Observed rise velocities of CO 2 droplets in seawater (35PSU) (a vast amount of work for a couple of lines …) WP18 pH change, Model (Enstad et al.)

The questions and challenges: What is going to happen? Spectrum of scenarios needed What are the uncertainties associated? If not reduction, then at least realistic estimate of uncertainties What if deliberate ocean storage comes back as a mitigation option? Have accurate scenarios at hand based on processes

Core Theme 5 talks on Tuesday: 13:00-13:15 Laurent Bopp, Overview on future scenarios 13:15-13:30 Thomas Froelicher, "Results from the NCAR CSM1.4-carbon model at Bern 13:30-13:45 Jochen Segschneider, Climate feedback on the carbon cycle 13:45-14:00 Karen Assmann, First results from the isopycnal HAMOCC model in MICOM/BCM 14:00-14:15 Jim Orr, High resolution tracer modeling 14:15-14:30 Gregor Rehder, Overview on deliberate storage