Ice-core evidence of late-holocene reduction in north Atlantic ocean heat transport

Richard B. Alley, Anna Mari Ágústsdóttir, Peter J. Fawcett

Research output: Chapter in Book/Report/Conference proceedingChapter

37 Citations (Scopus)

Abstract

The several-millennial cooling in central Greenland since the middle Holocene probably was caused by a trend to reduced oceanic heat transport as well as by orbital forcing, based on several lines of evidence. The late-Holocene trend is similar in many ways to the older coolings associated with abrupt, millennial climate changes. Climate records from Greenland ice cores indicate that both abrupt and gradual coolings involved: (i) greater temperature decrease in winter than in summer; (ii) greater accumulation-rate decrease in winter than in summer causing normally calibrated ice-isotopic changes to underestimate temperature changes; and (iii) increasing interannual climate variability. Paleoclimatic data and model results show that abrupt coolings have been linked to reduction in North Atlantic oceanic heat transport; we suggest that decreasing North Atlantic oceanic heat transport has also contributed to the Holocene trend. Gradual reductions in ocean heat transport precede abrupt reductions in both paleoclimatic records and model results, so it is likely that the natural trend has been toward the threshold for abrupt change in the late Holocene.

Original languageEnglish (US)
Title of host publicationMechanisms of Global Climate Change at Millennial Time Scales, 1999
EditorsLloyd D. Keigwin, Peter U. Clark, Robert S. Webb
PublisherBlackwell Publishing Ltd
Pages301-312
Number of pages12
ISBN (Electronic)9781118664742
ISBN (Print)9780875900957
DOIs
StatePublished - Jan 1 1999

Publication series

NameGeophysical Monograph Series
Volume112
ISSN (Print)0065-8448
ISSN (Electronic)2328-8779

Fingerprint

Atlantic Ocean
ice core
ice
Holocene
cooling
trends
heat
Greenland
winter
climate
summer
orbital forcing
climate change
accumulation rate
oceans
temperature
orbitals
thresholds
trend
North Atlantic Ocean

All Science Journal Classification (ASJC) codes

  • Geophysics

Cite this

Alley, R. B., Ágústsdóttir, A. M., & Fawcett, P. J. (1999). Ice-core evidence of late-holocene reduction in north Atlantic ocean heat transport. In L. D. Keigwin, P. U. Clark, & R. S. Webb (Eds.), Mechanisms of Global Climate Change at Millennial Time Scales, 1999 (pp. 301-312). (Geophysical Monograph Series; Vol. 112). Blackwell Publishing Ltd. https://doi.org/10.1029/GM112p0301
Alley, Richard B. ; Ágústsdóttir, Anna Mari ; Fawcett, Peter J. / Ice-core evidence of late-holocene reduction in north Atlantic ocean heat transport. Mechanisms of Global Climate Change at Millennial Time Scales, 1999. editor / Lloyd D. Keigwin ; Peter U. Clark ; Robert S. Webb. Blackwell Publishing Ltd, 1999. pp. 301-312 (Geophysical Monograph Series).
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Alley, RB, Ágústsdóttir, AM & Fawcett, PJ 1999, Ice-core evidence of late-holocene reduction in north Atlantic ocean heat transport. in LD Keigwin, PU Clark & RS Webb (eds), Mechanisms of Global Climate Change at Millennial Time Scales, 1999. Geophysical Monograph Series, vol. 112, Blackwell Publishing Ltd, pp. 301-312. https://doi.org/10.1029/GM112p0301

Ice-core evidence of late-holocene reduction in north Atlantic ocean heat transport. / Alley, Richard B.; Ágústsdóttir, Anna Mari; Fawcett, Peter J.

Mechanisms of Global Climate Change at Millennial Time Scales, 1999. ed. / Lloyd D. Keigwin; Peter U. Clark; Robert S. Webb. Blackwell Publishing Ltd, 1999. p. 301-312 (Geophysical Monograph Series; Vol. 112).

Research output: Chapter in Book/Report/Conference proceedingChapter

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Alley RB, Ágústsdóttir AM, Fawcett PJ. Ice-core evidence of late-holocene reduction in north Atlantic ocean heat transport. In Keigwin LD, Clark PU, Webb RS, editors, Mechanisms of Global Climate Change at Millennial Time Scales, 1999. Blackwell Publishing Ltd. 1999. p. 301-312. (Geophysical Monograph Series). https://doi.org/10.1029/GM112p0301