Until Now
EnvironmentScience

Dansgaard-Oeschger events

Greenland warms by 10 degrees in a few decades, twenty-five separate times.

When
Duration
103 thousand years
Known to
± 3 thousand years
Era
Late Pleistocene, Quaternary

Greenland ice cores record a series of abrupt warmings in which temperatures jump 8 to 16 degrees Celsius within decades, hold for centuries to millennia, then decline gradually before the next. Twenty-five are counted through the last glacial. They are tied to reorganisations of Atlantic overturning circulation and sea ice, and they show the climate system has modes it can flip between on human timescales — the single most unsettling result to come out of ice core science.

Just before

Just after