Rapid coupling between ice volume and polar temperature over the past 150,000 years

• Published in: Nature (London) 2012-11, Vol.491 (7426), p.744-747
• Main Authors: Grant, K. M., Rohling, E. J., Bar-Matthews, M., Ayalon, A., Medina-Elizalde, M., Ramsey, C. Bronk, Satow, C., Roberts, A. P.
• Format: Article
• Language: English
• Subjects: 704/106/125; Age; Animals; Antarctic Regions; Anthozoa; Archives & records; Atmospheric temperature; Climate; Climate change; Climate Change - history; Climate Change - statistics & numerical data; Climatic changes; Confidence intervals; Earth sciences; Earth, ocean, space; Environmental aspects; Exact sciences and technology; Feedback; Foraminifera - isolation & purification; Geologic Sediments - analysis; Global warming; Greenland; History, Ancient; Humanities and Social Sciences; Ice; Ice Cover - chemistry; Indian Ocean; letter; Marine and continental quaternary; Mediterranean Sea; Methods; multidisciplinary; Plankton - isolation & purification; Science; Sea ice; Sea level; Seawater - analysis; Seawater - chemistry; Surficial geology; Temperature; Time Factors
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature11593

A new approach to dating a continuous sea-level record, using speleothem U–Th ages, shows that past variations in global ice volume occurred within centuries of polar climate change, with rates of sea-level rise reaching at least 1 metre per century. A 150,000-year sea-level record Global sea level and the extent of the Greenland and Antarctic ice sheets are inextricably linked, but the precise timing of their changes has been unclear because it is difficult to obtain consistently and accurately dated long-term sea-level records. Here, the authors provide a markedly improved chronology of sea-level changes in the Red Sea during the past 150,000 years by cross-referencing to a more easily dateable record in the eastern Mediterranean. They find that sea level is linked to climate variation in both the Greenland and Antarctic ice sheets on a centennial scale, but more so to Antarctica. Sea level seems to lag the Antarctic climate by a few hundred years; it is tied more contemporaneously to Greenland's climate. Current global warming necessitates a detailed understanding of the relationships between climate and global ice volume. Highly resolved and continuous sea-level records are essential for quantifying ice-volume changes. However, an unbiased study of the timing of past ice-volume changes, relative to polar climate change, has so far been impossible because available sea-level records either were dated by using orbital tuning or ice-core timescales, or were discontinuous in time. Here we present an independent dating of a continuous, high-resolution sea-level record 1 , 2 in millennial-scale detail throughout the past 150,000 years. We find that the timing of ice-volume fluctuations agrees well with that of variations in Antarctic climate and especially Greenland climate. Amplitudes of ice-volume fluctuations more closely match Antarctic (rather than Greenland) climate changes. Polar climate and ice-volume changes, and their rates of change, are found to covary within centennial response times. Finally, rates of sea-level rise reached at least 1.2 m per century during all major episodes of ice-volume reduction.