The 8.2 ka event from Greenland ice cores

Quaternary Science Reviews, Vol. 26, 1-2, doi:10.1016/j.quascirev.2006.07.017, 2007

E.R. Thomas, E.W. Wolff and R. Mulvaney
British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3-0ET, UK.
J.P. Steffensen and S.J. Johnsen
Ice and Climate, The Niels Bohr Institute, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark
C. Arrowsmith
NERC Isotope Geosciences Laboratory, British Geological Survey, Kingsley Dunham Center, Keyworth, Nottingham NG12-5GG, UK.
J.W.C. White, B. Vaughn and T. Popp
Institute of Arctic and Alpine Research and Department of Geological Sciences, Campus Box 450, University of Colorado, Boulder, CO 80309, USA.

We present a collection of high-resolution chemistry and stable isotope records from the plateau of the Greenland ice cap during the cold event 8200 yr ago. Using a composite of four records, the cold event is observed as a 160.5 yr period during which decadal-mean isotopic values were below average, within which there is a central event of 69 yr during which values were consistently more than one standard deviation below the average for the preceding period. Four cores in north, south, and central Greenland show differences at decadal and shorter timescales; it is not yet clear if this represents significant spatial differences in response. The results show clear evidence for colder temperatures and a decrease in snow-accumulation rate. However, the changes in chemical concentrations for the ions looked at here are small, suggesting only minor changes in atmospheric circulation for this event. Apart from the decrease in methane concentration, Greenland ice cores give only weak evidence for effects outside the North Atlantic region.