CCSM Biogeochemistry WG Plans CCSM1-carbon Interactive land (CASA’) and ocean (OCMIP’) C cycles; prognostic CO2 for atmospheric radiation Planned submission to IPCC 4th Assessment CCSM3-carbon Port CASA’/OCMIP’ to CCSM3 physics Thornton’s new land model (C-N coupling, disturbance) More advanced ocean (marine ecosystem dynamics) CCSM3-carbon+ Dust  marine productivity  C Land atmosphere coupling and active chemistry

Predicting Co-evolution of CO2 and Climate Atmosphere CO2 = 280 ppmv (560 PgC) + … Ocean Circ. + BGC Biophysics 37400 Pg C 2000 Pg C 90± 60± Turnover Time of C 102-103 yr time of C 101 yr Fossil Fuel ~6 PgC/yr

} Land BGC Module CO2 NPP R_h GPP R_a H2O Energy LAI Sfc Metab Soil Struc Coarse Wdy Debris Microb Slow Passive NPP R_h Leaf Root Wood GPP R_a allocation H2O Energy LAI Based on coupling of CASA BGC & Land Biogeophysics dynamic allocation prognostic LAI and phenolgy

Marine BGC Module OCMIP Biotic Model + prognostic export production iron limitation and cycling

Coupling and Spin-up Strategy CCSM 1.4 physics (with some changes) at T31/x3 CTracer=prog CBGC=280 CRad=280 CTracer=prog CBGC=prog CRad=280 CTracer=prog CBGC=prog CRad=prog land BGC spin-up active land/atm clim. or coupled model SSTs O(102)y coupled physics land/ocn BGC adjustment coupled physics land/ocn/atm BGC adjustment coupled physics fully coupled carbon-climate ocean BGC spin-up active ocean O(103)y c4.11 100 yr c4.14 50 yr c4.15 ~100 yr (11/5/03) start from y=25 of c4.14 280 ppm

Carbon/Climate Control Simulation (~100y) +1.0 14.1 -1.0 Net CO2 Flux 13.7 Surface Temp. 284 283 “Stable” carbon cycle and climate over O(100y) with fully prognostic land/ocn BGC and carbon/radiation coupling 282 Surface Atm. CO2

Time-evolving, 3-D Atmospheric CO2 fields

CCSM1-carbon Control and Fossil Fuel Experiments Control (c4.15) 300 yr 1000 yr 1) Prescribed CO2 Emissions CO2/Radiation Coupling Run ensembles when feasible 2) Prescribed CO2 Emissions No CO2/Radiation Coupling 3) Prescribed CO2 Concentrations CO2/Radiation Coupling

CCSM Carbon-Climate GCM’s for IPCC 2007 CASA’ OCMIP’+Fe NCAR Origin (LANL) Doney, Fung, John, Lindsay CCSM 3.? IBM SP’s NCAR (ORNL, NERSC) Fung, Doney, John, Lindsay, Wehner, others? CLM3 Ocean Eco Thornton, Mahowald, Lindsay, Moore, Fung, Doney

New Land BGC model -Nitrogen/Carbon Coupling -Disturbance N-limited NEE response to +1° C step change (decid broadleaf) N-limited Illustration of the influence of nitrogen cycle dynamics on the carbon cycle response to forced climate variation. The same model has been run with (solid line) and without (dashed line) nitrogen cycle dynamics. Results shown for a single grid cell in the temperate deciduous broadleaf forest region of eastern U.S. summary: N cycle dynamics change both the sign and the time constant for sensitivity of terrestrial NEE to temperature. non N-limited

Model GPP, Conterminous U.S. 18-year mean from coupled carbon-nitrogen cycle model Summary: We are developing global and high-resolution regional modeling frameworks in parallel, to improve our ability to address science questions at policy-relevant spatial and temporal scales.

New Marine Ecosystem Model Physical Framework -global POP-CCSM 2.0 (x3 grid) -multi-decade solutions OCMIP-Fe BGC Model -ballast-model particle sinking and remineralization -Fe scavenging as function of particle flux -coastal sediment Fe source Multi-element, multi-functional group (Moore et al. 2002) -fixed C/N/P elemental ratios (21 vs. 46 tracers) -variable Fe/C & Si/C Moore, Doney & Lindsay (in prep.)

Future/ongoing work Upper Ocean Ecosystem Model -global seasonal evaluation (draft manuscript) -historical and JGOFS time-series/process study sites -interannual variability (climate & dust flux) Eco-BGC Coupling -quasi-equilibrium solutions (w/ LANL) -particle flux/ballast model -sediments (w/ U. Chicago)

A less dusty future? Mahowald and Luo, 2003 Simulations using CSM 1for the first time make estimates of future dust emissions. Use 6 different scenarios Estimates suggest 20-60% lower emissions/deposition in the future (sensitive to model). Estimates in pre-industrial sensitive to case (ice core data does not constrain). Important implications: ‘natural’ aerosols such as mineral aerosols are HIGHLY sensitive to human activities. Important impacts on climate and ocean uptake of CO2 suggest significant feedbacks due to ‘natural’ aerosol changes

Future Natural Aerosol Work Online coupled simulations with other aerosols Online coupled simulations with ocean biogeochemistry Plans to include sea salts and ‘natural’ biomass burning aerosol impacts Paleoclimate simulations to test model sensitivity and important feedbacks

N forcing Summary for Policymakers, IPCC 2001

Putting the pieces together: The GLOBAL C CYCLE The GLOBAL N CYCLE

Summary: Including new sunlit vs Summary: Including new sunlit vs. shaded canopy integration increases global GPP by 50%. Including realistic treatment of specific leaf area increases global GPP by an additional 15%. Global target value is around 120 PgC/yr.

Harvest loss: 11278 gC m-2 Summary: Continuing to quantify the dominant factors affecting net terrestrial carbon exchange on decadal and longer timescales. Shown here are the relative effects of a 50% harvest, a 1 degree C temperature increase, an 80 ppmv increase in CO2, and a doubling of atmospheric N deposition, at Duke Forest. Top plots shown without harvest to resolve dynamics in the other factors. Bottom plots show that harvest dominates the other factors across timescales.

What are the implications of N deposition for the global carbon cycle with a simple perturbation approach? from Holland et al 1997, JGR Atmospheres 102:15,849-15,866).