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Nature 261, 116 - 118 (13 May 1976); doi:10.1038/261116a0

Modulation of atmospheric carbon dioxide by the Southern Oscillation


Scripps Institution of Oceanography, University of California, La Jolla, California 92093

ATMOSPHERIC CO2 records for the South Pole and Mauna Loa Observatory, Hawaii, show a seasonal variation, presumably arising from the uptake and release of CO2 by vegetation, and a long term increase, almost certainly caused by combustion of fossil fuel. The increase is much greater in some years than in others1,2. Changes in the rate of fossil fuel combustion are not likely to be the cause of the variation in yearly increase, as combustion has increased very steadily3. I present here evidence that the variation is connected to the Southern Oscillation, a large scale atmospheric and hydrospheric fluctuation with an irregular period of 1–5 yr (ref. 4). The connection, if present, indicates that a principal cause of the variation may be a change in the rate of removal of CO2 by the oceans.



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