During the last ice age, the Barents Sea ice sheet began to grow 22 ky
r ago(1), only 8 kyr before it began to disintegrate(2). This implies
that the ice must have grown very rapidly from the coast to the edge o
f the continental shelf. Such rapid growth of a large ice sheet requir
es significant amounts of moisture; but the origin of this moisture ha
s been unclear, particularly as the CLIMAP climate reconstruction sugg
ests(4,5) that the Greenland-Iceland-Norwegian (GIN) seas were perenni
ally ice-covered during this period. Here we present data from deep-se
a sediment cores from the Fram Strait, which suggest that relatively w
arm water from the North Atlantic Ocean was advected into the GIN seas
in two short-term events (27-22.5 and 19.5-14.5 kyr ago). We suggest
that the resulting seasonally ice-free waters were an important region
al moisture source for the Barents Sea ice sheet, and that the GIN sea
s played a much more active role in climate during the last glaciation
than has previously been supposed.