Atmospheric Carbon Dioxide, Orbital Forcing, and Climate

  1. E.T. Sundquist and
  2. W.S. Broecker
  1. N. J. Shackleton1 and
  2. N. G. Pisias2

Published Online: 18 MAR 2013

DOI: 10.1029/GM032p0303

The Carbon Cycle and Atmospheric CO: Natural Variations Archean to Present

The Carbon Cycle and Atmospheric CO: Natural Variations Archean to Present

How to Cite

Shackleton, N. J. and Pisias, N. G. (1985) Atmospheric Carbon Dioxide, Orbital Forcing, and Climate, in The Carbon Cycle and Atmospheric CO: Natural Variations Archean to Present (eds E.T. Sundquist and W.S. Broecker), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM032p0303

Author Information

  1. 1

    Godwin Laboratory for Quaternary Research, University of Cambridge, Cambridge CB2 3RS, England

  2. 2

    College of Oceanography, Oregon State University, Corvallis, Oregon 97331

Publication History

  1. Published Online: 18 MAR 2013
  2. Published Print: 1 JAN 1985

ISBN Information

Print ISBN: 9780875900605

Online ISBN: 9781118664322

SEARCH

Keywords:

  • Carbon cycle (Biogeochemistry)—Congresses;
  • Atmospheric carbon dioxide—Congresses;
  • Geological time—Congresses;
  • Paleothermometry—Congresses;
  • Geology, Stratigraphic—Congresses

Summary

We have analyzed a 340,000-year record of benthic and planktonic oxygen and carbon isotope measurements from an equatorial Pacific deep-sea core. The data provide estimates of both global ice volume and atmospheric carbon dioxide concentration over this period. The frequencies characteristic of changes in the earth-sun orbital geometry dominate all the records. Examination of phase relationships shows that atmospheric carbon dioxide concentration leads ice volume over the orbital bandwidth, and is forced by orbital changes through a mechanism, at present not fully understood, with a short response time. Changes in atmospheric CO2 are not primarily caused by glacial-interglacial sea level changes, which had been hypothesized to affect atmospheric CO2 through the effect on ocean chemistry of changing sedimentation on the continental shelves. Instead, variations in atmospheric CO2 should be regarded as part of the forcing of ice volume changes.