GOSAC Objective 2

For Objective 2, GOSAC will investigate the ocean's capacity to store additional CO2 injected directly into the deep.
GOSAC will provide an envelope of predictions from at least seven diverse models concerning

1. Work Content

1.1 Methodology

To achieve Objective 2, GOSAC must determine the time scale for eventual loss to the atmosphere of additional CO2 stored in the ocean, which determines the effectiveness of ocean CO2 storage as one means to help mitigate rising levels of atmospheric CO2.

Details of planned simulations:

  1. Initial conditions: present day (1990) state (OCMIP natural + OCMIP anthropogenic CO2 runs);
  2. Post-1990 fossil emissions: injected into each model's 1-box atmosphere
  3. Control run: use GOSAC-IEAGHG emissions scenario (to be determined)
  4. Injection runs: use same scenario minus 0.6 GT C/yr in the atmosphere. Simultaneously, 0.7 GT C/yr (total) will be injected into the ocean. The difference, 0.1 GT C/yr is associated with the cost of sequestering CO2 in the ocean
  5. Seven sites (to be determined as a fnction of practical and oceanographic considerations);
  6. Three depths at each site (e.g., 800, 1500, and 3000 m);
  7. Three injection runs; 2 control runs
  8. Simultaneous injection runs will require that each site have a separate tracer for DIC (total dissolved inorganic carbon) so that both the individual and the total effect of the injected carbon can be identified. A preliminary study by the IEA GHG postdoc, Olivier Aumont, will determine if nonlinearities associated with carbonate chemistry and interaction between plumes) are important. If interactions are substantial, protocols will be modified.
  9. Amount: 0.1 GT C/yr will be injected at each site
  10. Duration of injection: 100 yr
  11. Duration of complete simulation: 1000 yr
  12. Analysis: will focus on the gain (injection run minus control) for associated perturbations in atmospheric CO2, air-sea CO2 fluxes, oceanic CO2, and oceanic pH.

1.2 Milestones

GOSAC milestones given below are offered with respect to the reporting dates at 12-month intervals from the beginning of GOSAC.

Year 1:

Year 2: Year 3:

1.3 Detailed Calendar

The GOSAC-IEAGHG effort is focused on analysis, which is distinguished as that done by the analysis center IPSL/LSCE (Base analysis) and that adopted by other GOSAC participants late in the project (Extended analysis). Base analysis is further broken down into primary, secondary, and tertiary analysis, according to complexity and dependence on results from previous analysis. Examples of each are provided below.

Target dates given below are offered quarterly from the beginning of GOSAC.

Month 3:

Month 6: Month 9: Month 12: Month 15: Month 18: Month 21: Month 24: Month 27: Month 30: Month 33: Month 36:

2. Role of Participants

2.1 Coordination

Dr. James Orr (IPSL/LSCE) Dr. Olivier Aumont (GOSAC-IEAGHG postdoc)

3.2 Other Responsibilities

The responsibility of the other partners is stipulated in the GOSAC Work Programme for the EC Environment and Climate Programme.

3.3 Interdependence between tasks

As shown in the timetable, GOSAC-EC simulations for natural CO2 must be completed before GOSAC-EC simulations for industrial-era anthropogenic CO2 (1765-1995) can begin. Output from these industrial era CO2 runs are the starting point for GOSAC CO2 ocean injection and business-as-usual simulations. GOSAC-IEAGHG analysis relies upon receiving model output, in a timely manner, from all GOSAC participants.