Atmospheric carbon dioxide variations at the South Pole

Duplicate measurements of 749 discrete samples of air collected at the South Pole indicate that the seasonally adjusted concentration of atmospheric carbon dioxide in the polar southern hemisphere rose 3.7% between 1957 and 1971. The rise, mostly attributable to the burning of fossil fuels, has not been steady. In the mid-1960's, possibly as a result of wide-spread cooling of surface ocean water, it slackened for several years; recently it has accelerated. Similar changes in rate have also been observed at Mauna Loa Observatory, Hawaii, in the northern hemisphere and are evidently a global phenomenon.