A salt oscillator in the glacial Atlantic? 1. The concept

TLDR

Glacial Greenland ice cores reveal millennial‑scale climate oscillations of ~5 °C temperature swings, dust and CO₂ variations, attributed to changes in ocean circulation modes. This study seeks to demonstrate that comparable millennial‑scale surface‑water oscillations are recorded in a deep‑sea core at 50° N. By analyzing the deep‑sea core record at 50° N, the authors identify surface‑water condition oscillations of similar duration. The authors conclude that Greenland climate changes are driven by Atlantic salinity oscillations that modulate the strength of the Atlantic Meridional Overturning Circulation.

Abstract

As shown by the work of Dansgaard and his colleagues, climate oscillations of one or so millennia duration punctuate much of glacial section of the Greenland ice cores. These oscillations are characterized by 5°C air temperature changes, severalfold dust content changes and 50 ppm CO 2 changes. Both the temperature and CO 2 change are best explained by changes in the mode of operation of the ocean. In this paper we provide evidence which suggests that oscillations in surface water conditions of similar duration are present in the record from a deep sea core at 50°N. Based on this finding, we suggest that the Greenland climate changes are driven by oscillations in the salinity of the Atlantic Ocean which modulate the strength of the Atlantic's conveyor circulation.