A low climate threshold for south Greenland Ice Sheet demise during the Late Pleistocene

Nil Irvalı, Eirik V. Galaasen, Ulysses S. Ninnemann, Yair Rosenthal, Andreas Born, Helga F. Kleiven

Research output: Contribution to journalArticle

Abstract

The Greenland Ice Sheet (GIS) has been losing mass at an accelerating rate over the recent decades. Models suggest a possible temperature threshold between 0.8 and 3.2 °C, beyond which GIS decline becomes irreversible. The duration of warmth above a given threshold is also a critical determinant for GIS survival, underlining the role of ocean warming, as its inertia prolongs warmth and triggers longer-term feedbacks. The exact point at which these feedbacks are triggered remains equivocal. Late Pleistocene interglacials provide potential case examples for constraining the past response of the GIS to a range of climate states, including conditions warmer than present. However, little is known about the magnitude and duration of warming near Greenland during these periods. Using high-resolution multiproxy surface ocean climate records off southern Greenland, we show that the previous 4 interglacials over the last ∼450 ka all reached warmer than present climate conditions and exceeded the modeled temperature threshold for GIS collapse but by different magnitudes and durations. Complete deglaciation of the southern GIS in Marine Isotope Stage 11c (MIS 11c; 394.7 to 424.2 ka) occurred under climates only slightly warmer than present (∼0.5 ± 1.6 °C), placing the temperature threshold for major GIS retreat in the lower end of model estimates and within projections for this century.

Original languageEnglish (US)
Pages (from-to)190-195
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume117
Issue number1
DOIs
StatePublished - Jan 7 2020

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All Science Journal Classification (ASJC) codes

  • General

Keywords

  • Climate change
  • Greenland Ice Sheet
  • Late Pleistocene interglacials
  • Thresholds

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