Sediment cores from the Polar North Atlantic provide evidence of six p
eriods of sea-ice breakup during isotope stages 4, 3, and 2, probably
caused by inflow of North Atlantic surface water into the Polar North
Atlantic, These periods are characterized by having a high number of f
oraminifera/g; they last from 2000 to > 10 000 yr, and constitute simi
lar to 50% of the total time span. These periods of sea-ice breakup co
rrelate temporarily to the Heinrich events and the early temperature m
aximum in the Bond cycles of the North Atlantic and Greenland ice reco
rd, Our hypothesis is that massive iceberg discharges that flooded the
North Atlantic during each Heinrich event probably triggered an ocean
ographic regime that gave a much more vigorous surface circulation pat
tern in the Polar North Atlantic, which contributed to the breakup of
the sea-ice cover, Open-water conditions in the Polar North Atlantic a
re inversely related to terrestrial interstadials of coastal Norway, s
uggesting ice-sheet starvation during the cold periods and ice-sheet g
rowth when an open-water surface circulation existed in the Polar Nort
h Atlantic, Our data document synchronous variations on a 1000 yr time
scale between Arctic oceanic climate, Northern Hemisphere ice-sheet d
ynamics, and ocean-atmosphere temperature changes.