Is There a Tie between Atmosphere CO2 Content and Ocean Circulation?

  1. James E. Hansen and
  2. Taro Takahashi
  1. Wallace S. Broecker and
  2. Taro Takahashi

Published Online: 19 MAR 2013

DOI: 10.1029/GM029p0314

Climate Processes and Climate Sensitivity

Climate Processes and Climate Sensitivity

How to Cite

Broecker, W. S. and Takahashi, T. (1984) Is There a Tie between Atmosphere CO2 Content and Ocean Circulation?, in Climate Processes and Climate Sensitivity (eds J. E. Hansen and T. Takahashi), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM029p0314

Author Information

  1. Lamont-Doherty Geological Observatory of Columbia University, Palisades, New York 10964

Publication History

  1. Published Online: 19 MAR 2013
  2. Published Print: 1 JAN 1984

ISBN Information

Print ISBN: 9780875904047

Online ISBN: 9781118666036

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Keywords:

  • Climatology—Congresses;
  • Geophysics—Congresses;
  • Ocean-atmosphere interaction—Congresses

Summary

The possibility that the CO2 partial pressure of the surface waters of the ocean (and hence also of the atmosphere) is dependent on the rates of oceanic mixing is explored. The purpose of this exercise is to ascertain whether the abrupt rise in atmospheric CO2 content at the end of the last glacial period could have been caused by a reorganization of deep sea ventilation. We also have our eye on the possibility that future warming of the planet induced by anthropogenic CO2 will lead to a positive feedback (i.e., polar warming, reduced deep sea ventilation rate, increase in the PCO2 of surface ocean water). Our approach is to consider two end member models for the distribution of CO2 in the sea. One is thermodynamic, the other is biological. The surface water PCO2 difference between these end member models is nearly a factor of two. We show that the situation for the real ocean likely lies between these extremes and explore how the ratio of deep sea ventilation rate to air-sea CO2 exchange rate might push the system closer to one extreme or the other. It appears that decreases in the ventilation rate will push the ocean closer to the thermodynamic end member and hence raise the atmosphere's PCO2. Such a decrease in ventilation rate may have occurred at the end of glacial time. A further decrease may be induced during the next hundred or so years by the buildup of CO2 in the atmosphere.