EAPS
PAOC Colloquium: Galen McKinley (LDEO)
| Date |
Time |
Location |
| April 2nd, 2018 |
12:00pm-1:00pm |
Ida Green Lounge (9th Floor), Building 54, Cambridge MA, United States |
Title: Diagnosing change in the ocean carbon sink
Abstract: Since preindustrial times, theocean has absorbed an excess of carbon equivalent to 41% of cumulative fossilfuel emissions, and thus has significantly slowed atmospheric CO2growth and the resulting climate change. Ocean carbon uptake is expected to growsubstantially through 2100. Thus, international climate policy efforts requirethe carbon cycle science community to regularly diagnose ocean carbon fluxesand to distinguish changes in atmospheric CO2 due to naturalvariability from changes due to emission cuts. Our analysis of 35 years of surfaceocean pCO2 observations illustrates significant large-scale variabilityon interannual to decadal timescales. If the expected long-term growth in the oceancarbon sink is to be directly detected, the growth signal must emerge from thenoise of this variability. We predict emergence timescales using a large ensembleof the NCAR climate model (NCAR-LENS). The forced trend in carbon uptake islargest and emerges most quickly at the high latitudes. In the subtropics, thesink grows slowly and does not emerge until late in the century. Surface oceanpCO2 observations indicate carbon sink growth consistent with thepredicted emergence only in the North Pacific; elsewhere, variability continuesto dominate.