Geochemical and climate impact on CO2 fluxes

1
Geochemical and climate impact on CO2 fluxes
Air-sea CO2 exchanges are driven by
thermodynamics, biological activity and ocean
mixing. But theses processes are affected on
short term by climate variability (see El-Niño in
Equatorial Pacific or waves in Austral ocean) and
on long term by increasing atmospheric CO2 (see
how Austral ocean will be converted in a major
sink in mid XXI century). Simulation had been
made with the coupled climate carbon model
IPSL-CC1. Pre-industrial state had been perturbed
by the historical emissions followed by the IPCC
SRES98-A2 scenario since 1995. After Bopp et
al., 2000
2
Potential climate impacton marine production
A warming climate (see SST) could significantly
stratify the ocean. This will reduce upwelling of
deep nutrients (see Phosphates), except near
Antarctica where deep convection cells could
shift after sea-ice melting. Consequently, marine
activity (see Export Production) could be reduced
by nutrients changes at low and mid latitudes,
but also enhanced at high latitudes by light
availability along a longer growing season.
Simulation had been made with the coupled climate
carbon model IPSL-CC1. Pre-industrial state had
been perturbed by the historical emissions
followed by the IPCC SRES98-A2 scenario since
1995. After Bopp et al., 2000
Anomalies only are displayed
3
Austral storage of CFC-11
Penetration of anthropogenic CFC-11 could trace
deep convection areas around Antarctica. Here are
presented the evolution of water column inventory
along the last two decades. The results are from
simulations made by 11 OGCMs, participating in
the second phase of the Ocean Carbon-cycle Model
Intercomparison Project (OCMIP-II). Models that
exhibit 3 convection areas (Weddell, Ross and off
Adelie Land) are more coherent with recent WOCE
datasets. After Dutay et al., 2000