The role of oceanic forcing in mid-Holocene Northern Hemisphere climatic change

Michael W. Kerwin, Jonathan Overpeck, Robert S. Webb, Anne DeVernal, David H. Rind, Richard J. Healy

Research output: Contribution to journalArticle

60 Citations (Scopus)

Abstract

Previous model investigations suggested that changes in orbital forcing and feedbacks associated with northward expansion of the boreal forest were both required to explain the full magnitude of enhanced high-latitude Northern Hemisphere summer warming at 6 ka, thus implying that biospheric feedbacks (decreased planetary albedo associated with forest expansion) may be large in the future [Foley et al., 1994; TEMPO (Testing Earth System Models with Paleo-Observations), 1996]. Before the magnitude of past biospheric and other feedbacks can be estimated with confidence, however, the role of realistic high-latitude oceanic forcing (i.e., sea surface temperature (SST) increases and sea ice reductions) should also be considered. Here we review existing paleoceanographic observations that suggest portions of the North Atlantic were up to 4°C warmer than today at 6 ka. We then combine our estimates of mid-Holocene North Atlantic SST and sea ice conditions with new climate model simulations to suggest that a significant portion of high-latitude summer warming at 6 ka in the Northern Hemisphere can be accounted for by altered orbital forcing, SSTs, and sea ice relative to today. Our results underscore the importance of incorporating realistic boundary conditions when using paleoenvironmental data to evaluate the climate system's sensitivity to altered forcing and suggest that high-latitude oceanic feedbacks were major contributors to enhanced high-latitude summer warming in the Northern Hemisphere at 6 ka.

Original languageEnglish (US)
Pages (from-to)200-210
Number of pages11
JournalPaleoceanography
Volume14
Issue number2
DOIs
StatePublished - Apr 1999
Externally publishedYes

Fingerprint

Northern Hemisphere
Holocene
climate change
sea ice
orbital forcing
sea surface temperature
warming
summer
boreal forest
albedo
climate modeling
boundary condition
climate
simulation

ASJC Scopus subject areas

  • Oceanography
  • Palaeontology

Cite this

Kerwin, M. W., Overpeck, J., Webb, R. S., DeVernal, A., Rind, D. H., & Healy, R. J. (1999). The role of oceanic forcing in mid-Holocene Northern Hemisphere climatic change. Paleoceanography, 14(2), 200-210. https://doi.org/10.1029/1998PA900011

The role of oceanic forcing in mid-Holocene Northern Hemisphere climatic change. / Kerwin, Michael W.; Overpeck, Jonathan; Webb, Robert S.; DeVernal, Anne; Rind, David H.; Healy, Richard J.

In: Paleoceanography, Vol. 14, No. 2, 04.1999, p. 200-210.

Research output: Contribution to journalArticle

Kerwin, MW, Overpeck, J, Webb, RS, DeVernal, A, Rind, DH & Healy, RJ 1999, 'The role of oceanic forcing in mid-Holocene Northern Hemisphere climatic change', Paleoceanography, vol. 14, no. 2, pp. 200-210. https://doi.org/10.1029/1998PA900011
Kerwin, Michael W. ; Overpeck, Jonathan ; Webb, Robert S. ; DeVernal, Anne ; Rind, David H. ; Healy, Richard J. / The role of oceanic forcing in mid-Holocene Northern Hemisphere climatic change. In: Paleoceanography. 1999 ; Vol. 14, No. 2. pp. 200-210.
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