"Records from Greenland ice cored in the early 1990's clearly demonstrate that during glacial time the climate of the northern Atlantic region underwent abrupt jumps from one state of operation to another," Dr. Broecker said. "Climate appears to have remained locked in one such state for a millennium or so and then during a period as short as a few decades jumped to another."
or decades as Broecker's research indicates.
source same as above.
