On the global sea level change during the Late Quaternary

Abstract

The study is aimed at identifying the most general patterns of changes in the average global sea level in the Late Quaternary (the last 800 thousand years). The factual material used included recently published most detailed and reliable stacked series of the Global Sea Level (GSL) and Global Mean Surface Temperature (GMST) for the given time interval. On the scale of a 100-ka cycle, a simple linear relationship is observed between the two parameters (lower temperature – lower sea level), but upon closer examination, unusual features are revealed: 1) sea level maxima and minima are delayed relative to temperature maxima and minima by 4.7 ± 1.1 and 7.8 ± 2.1 thousand years, respectively; 2) ocean low stands are observed at approximately the same GMST anomalies (–4.7 ± 0.2 °C relative to the pre-industrial), while there is no correlation with the sea level value itself. The situation with the ocean high stands is similar. According to our hypothesis, the apparent delay in the sea level is explained by the fact that the maximum (minimum) ocean levels are not related to temperature per se, but to the accumulated sum of positive (negative) temperature anomalies over the previous warm (cold) period. In other words, the sea level series is a function of the integral-difference curve (IDC) of temperature. To illustrate this hypothesis, we have constructed a temperature IDC for the time interval between 460 and 360 thousand years ago, which satisfactorily explains the main trends in sea level change during marine isotope stages 12 and 11.