The Ocean Uptake of CO2 is an Incredibly Loose Cannon!
Oct 16, 2007
from 09:30 AM to 10:30 AM
|Where||Foothills Laboratory, Room 1022|
|Contact Name||Bill Brown|
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NCAR-EOL Affiliate Scientist
University of Hawaii Professor of Oceanography
While present and past CO2 budgets are very well constrained by observed atmospheric increases, isotopic measurements, and highly accurate O2 measurements, the future CO2 budget is far less certain. Studies of paleo variability are of limited use in forecasting, since we are already at CO2 concentrations far above any the inhabited Earth has experienced.
For predictions of future ocean CO2 uptake we must use F = Vt Δp CO2 where F is the air-sea flux, Vt is an exchange velocity, and Δp CO2 is the concentration (actually, fugacity) difference across the interface. Existing models of Vt are uncertain to at least a factor of two and depend in unknown ways on factors including wind, surfactant films, wave characteristics, and bubbles, among others. Our ignorance of the quantitative controls on Vt propagate to an alarming uncertainty in the future increase rate of atmospheric CO2. Inversion models that rely on wind-only exchange velocity models are similarly uncertain. There are things that could be done to improve on this situation.
The IPCC chose not to examine the role of ocean CO2 uptake uncertainty in its Fourth Assessment.