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Arctic freshwater forcing of the Younger Dryas cold reversal


The last deglaciation was abruptly interrupted by a millennial-scale reversal to glacial conditions1, the Younger Dryas cold event. This cold interval has been connected to a decrease in the rate of North Atlantic Deep Water formation and to a resulting weakening of the meridional overturning circulation2,3,4 owing to surface water freshening. In contrast, an earlier input of fresh water (meltwater pulse 1a), whose origin is disputed5,6, apparently did not lead to a reduction of the meridional overturning circulation4. Here we analyse an ensemble of simulations of the drainage chronology of the North American ice sheet in order to identify the geographical release points of freshwater forcing during deglaciation. According to the simulations with our calibrated glacial systems model, the North American ice sheet contributed about half the fresh water of meltwater pulse 1a. During the onset of the Younger Dryas, we find that the largest combined meltwater/iceberg discharge was directed into the Arctic Ocean. Given that the only drainage outlet from the Arctic Ocean was via the Fram Strait into the Greenland–Iceland–Norwegian seas7, where North Atlantic Deep Water is formed today, we hypothesize that it was this Arctic freshwater flux that triggered the Younger Dryas cold reversal.

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Figure 1: Major deglacial drainage outlets for North America, along with approximate positions of proglacial Lake Agassiz and Keewatin dome just before the onset of the YD.
Figure 2: Eustatic sea-level chronologies.
Figure 3: Computed regional drainage chronologies and the inferred regional temperature change chronology.


  1. 1

    Dansgaard, W. et al. Evidence for general instability of past climate from a 250 kyr ice-core record. Nature 264, 218–220 (1993)

    ADS  Article  Google Scholar 

  2. 2

    Keigwin, L. D., Jones, J. A., Lehman, S. J. & Boyle, E. A. Deglacial meltwater discharge, North-Atlantic deep circulation, and abrupt climate change. J. Geophys. Res. 96, 16811–16826 (1991)

    ADS  Article  Google Scholar 

  3. 3

    Muscheler, R., Beer, J., Wagner, G. & Finkel, R. Changes in deep-water formation during the Younger Dryas event inferred from 10Be and 14C records. Nature 408, 567–570 (2000)

    ADS  CAS  Article  Google Scholar 

  4. 4

    McManus, J. F., Francois, R., Gherardi, J.-M., Keigwin, L. D. & Brown-Leger, S. Collapse and rapid resumption of Atlantic meridional circulation linked to deglacial climate changes. Nature 428, 834–837 (2004)

    ADS  CAS  Article  Google Scholar 

  5. 5

    Clark, P. et al. Origin of the first global meltwater pulse following the last glacial maximum. Paleoceanography 11, 563–577 (1996)

    ADS  Article  Google Scholar 

  6. 6

    Peltier, W. R. On the hemispheric origins of meltwater pulse 1-a. Quat. Sci. Rev. (in the press)

  7. 7

    Dyke, A. S. in Quaternary Glaciations—Extent and Chronology, Part II, Vol. 2b (eds Ehlers, J. & Gibbard, P. L.) 373–424 (Elsevier Science and Technology Books, Amsterdam, 2004)

    Book  Google Scholar 

  8. 8

    Stocker, T. F. & Schmittner, A. Influence of carbon dioxide emission rates on the stability of the thermohaline circulation. Nature 388, 862–865 (1997)

    ADS  CAS  Article  Google Scholar 

  9. 9

    Manabe, S. & Stouffer, R. J. Coupled ocean-atmosphere model response to freshwater input: comparison to Younger Dryas event. Paleoceanography 12, 321–336 (1997)

    ADS  Article  Google Scholar 

  10. 10

    de Vernal, A., Hillaire-Marcel, C. & Bilodeau, G. Reduced meltwater outflow from the Laurentide ice margin during the Younger Dryas. Nature 381, 774–777 (1996)

    ADS  CAS  Article  Google Scholar 

  11. 11

    Broecker, W. S. et al. Routing of meltwater from the Laurentide Ice Sheet during the Younger Dryas cold episode. Nature 341, 318–321 (1989)

    ADS  Article  Google Scholar 

  12. 12

    Parsons, J. D., Bush, J. W. & Syvitski, J. P. Hyperpycnal plume formation from riverine outflows with small sediment concentrations. Sedimentology 48, 465–478 (2001)

    ADS  Article  Google Scholar 

  13. 13

    Hemming, S. R. Massive late Pleistocene detritus layers of the North Atlantic and their global climate imprint. Rev. Geophys. 42, doi:10.1029/2003RG000128 (2004)

  14. 14

    Fisher, T. G., Smith, D. G. & Andrews, J. T. Preboreal oscillation caused by a glacial Lake Agassiz flood. Quat. Sci. Rev 21, 873–878 (2002)

    ADS  Article  Google Scholar 

  15. 15

    Bauch, H. A. et al. A multiproxy reconstruction of the evolution of deep and surface waters in the subarctic Nordic seas over the last 30,000 yr. Quat. Sci. Rev. 20, 659–678 (2001)

    ADS  Article  Google Scholar 

  16. 16

    Norgaard-Pedersen, N. et al. Arctic Ocean during the Last Glacial Maximum: Atlantic and polar domains of surface water mass distribution and ice cover. Paleoc. 18, doi:10.1029/2002PA000781 (2003)

  17. 17

    Tarasov, L. & Peltier, W. R. A geophysically constrained large ensemble analysis of the deglacial history of the North American ice sheet complex. Quat. Sci. Rev 23, 359–388 (2004)

    ADS  Article  Google Scholar 

  18. 18

    Dyke, A. S., Moore, A. & Robertson, L. Deglaciation of North America (Tech. Rep. Open File 1574, Geological Survey of Canada, Ottawa, 2003)

    Book  Google Scholar 

  19. 19

    Svendsen, J. I. et al. Late Quaternary ice sheet history of northern Eurasia. Quat. Sci. Rev. 23, 1229–1271 (2004)

    ADS  Article  Google Scholar 

  20. 20

    Tarasov, L. & Peltier, W. R. Terminating the 100 kyr ice age cycle. J. Geophys. Res. 102, 21665–21693 (1997)

    ADS  CAS  Article  Google Scholar 

  21. 21

    Aagaard, K. & Carmack, E. C. The role of sea ice and other fresh water in the Arctic circulation. J. Geophys. Res. 94, 14485–14498 (1989)

    ADS  Article  Google Scholar 

  22. 22

    Licciardi, J. M., Teller, J. T. & Clark, P. U. in Mechanisms of Global Climate Change at Millennial Time Scales (eds Clark, P. U., Webb, R. S. & Keigwin, L. D.) 177–201 (AGU Geophysical Monographs Vol. 112, American Geophysical Union, Washington DC, 1999)

    Book  Google Scholar 

  23. 23

    Marshall, S. J. & Clarke, G. K. C. Modeling North American freshwater runoff through the last glacial cycle. Quat. Res 52, 300–315 (1999)

    Article  Google Scholar 

  24. 24

    Peltier, W. R. Global glacial isostatic adjustment: Paleo-geodetic and space-geodetic tests of the ICE-4G (VM2) model. J. Quat. Sci. 17, 491–510 (2002)

    Article  Google Scholar 

  25. 25

    Teller, J. T. & Leverington, D. W. Glacial Lake Agassiz: a 5000 yr history of change and its relationship to the δ18O record of Greenland. Geol. Soc. Am. Bull. 116, 729–742 (2004)

    ADS  CAS  Article  Google Scholar 

  26. 26

    Teller, J. T., Boyd, M., Yang, Z., Kor, P. S. G. & Fard, A. M. Alternative routing of Lake Agassiz overflow during the Younger Dryas: New dates, paleotopography, and a reevaluation. Quat. Sci. Rev. (in the press)

  27. 27

    Dyke, A. S. & Prest, V. K. Late Wisconsinan and Holocene history of the Laurentide ice sheet. Géogr. Phys. Quat. 41, 237–264 (1987)

    Google Scholar 

  28. 28

    Vinje, T., Nordlund, N. & Kvambekk, A. Monitoring ice thickness in Fram Strait. J. Geophys. Res. 103, 10437–10449 (1998)

    ADS  Article  Google Scholar 

  29. 29

    Fairbanks, R. G. A 17,000-year glacio-eustatic sea level record: influence of glacial melting rates on the Younger Dryas event and deep-ocean circulation. Nature 342, 637–641 (1989)

    ADS  Article  Google Scholar 

  30. 30

    Tarasov, L. & Peltier, W. R. Greenland glacial history, borehole constraints and Eemian extent. J. Geophys. Res. 108, 2124–2143 (2003)

    Article  Google Scholar 

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This paper is a contribution to the Polar Climate Stability Research Network, which is funded by the Canadian Foundation for Climate and Atmospheric Sciences and a consortium of Canadian universities. We thank W. Broecker, A. Dyke, T. Fisher, C. Hillaire-Marcel and J. Teller for discussions.

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Correspondence to Lev Tarasov.

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Reprints and permissions information is available at The authors declare no competing financial interests.

Supplementary information

Supplementary Discussion

Two fluid dynamical issues concerning large meltwater discharge into the mid-Altantic or Gulf of Mexico are discussed. It is argued that it is unlikely for a large surface freshwater plume to be formed and/or advected intact to the sites of North Atlantic Deep Water Formation. This file also includes a supplementary discussion concerning the uncertainties pertaining to and the dynamical source of the spike in Arctic discharge during Younger Dryas onset, and Supplementary Figures S1-S3. (PDF 211 kb)

Supplementary_Figures S4-S6

Supplementary Figures S4-S6 detail computed -12.8 kyr drainage basins and surface topography for 3 good-fit ensemble runs. (PDF 366 kb)

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Tarasov, L., Peltier, W. Arctic freshwater forcing of the Younger Dryas cold reversal. Nature 435, 662–665 (2005).

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