Younger Dryas

The name internationally used for an abrupt climate change that occurred between 12,900 and 11,700 years before the present (1950, by convention) when the last glaciation was in retreat. This episode marked a sudden return (within a few decades) to glacial conditions in much of the northern hemisphere, according to what can be inferred from paleoclimatic records. It takes its name from an alpine tundra flower ( Dryas octopetala ), as remains of its leaves are frequently found in late glacial sediments.