Sea level and Antarctic temperature have been closely coupled over the past 520,000 years, according to a study online in Nature Geoscience. The report suggests that it takes several millennia for sea levels to adjust fully to changes in global mean temperature.

Eelco Rohling and colleagues compared reconstructions of global sea level from marine sediment records and Antarctic temperature records from ice cores over the past five glacial cycles. The statistical relationship derived from these records suggests that sea levels between 3 and 3.5 million years ago ― when atmospheric carbon dioxide levels were similar to today ― were between 20 and 30 metres higher than at present. The findings imply a strong response of sea levels to rising concentrations of atmospheric greenhouse gases on timescales of several thousand years.