Evidence for general instability of past climate from a 250-KYR ice-core record

Sigfus Johann Johnsen, Henrik Brink Clausen, Dorthe Dahl-Jensen, Claus Uffe Hammer, Christine Schøtt Hvidberg, Jørgen Peder Steffensen, W. Dansgaard, NS. Gundestrup, AE Sveinbjornsdottir, J. Jouzel, G. Bond

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Abstract

 results1,2 from two ice cores drilled in central Greenland have revealed large, abrupt climate changes of at least regional extent during the late stages of the last glaciation, suggesting that climate in the North Atlantic region is able to reorganize itself rapidly, perhaps even within a few decades. Here we present a detailed stable-isotope record for the full length of the Greenland Ice-core Project Summit ice core, extending over the past 250 kyr according to a calculated timescale. We find that climate instability was not confined to the last glaciation, but appears also to have been marked during the last interglacial (as explored more fully in a companion paper3) and during the previous Saale-Holstein glacial cycle. This is in contrast with the extreme stability of the Holocene, suggesting that recent climate stability may be the exception rather than the rule. The last interglacial seems to have lasted longer than is implied by the deep-sea SPECMAP record4, in agreement with other land-based observations5,6. We suggest that climate instability in the early part of the last interglacial may have delayed the melting of the Saalean ice sheets in America and Eurasia, perhaps accounting for this discrepancy
Udgivelsesdato: 15 juli
Original languageEnglish
JournalNature
Volume364
Pages (from-to)218-220
ISSN0028-0836
DOIs
Publication statusPublished - 1993

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