Climate Through Human History

The Younger Dryas Event

The end of the Ice Age world started about 15,000 B.C. and brought great changes to the landscape, including sea-level rise.

Temperatures of the Last 18,000 years

Warmer climate was short lived. Between 12,800 and 11,500 years ago a short but severe cold spell occurred. This period was named the "Younger Dryas" event after a arctic/alpine flower Dryas Octopetald which had returned to Britain during this period.

During the Younger Dryas period temperatures dropped by 7°C ( ~ 10°F) to near-glacial conditions in under 50 years.

Rapid ice melt

large amounts of of cold fresh water spreading into the North Atlantic

(Ocean circulation controlled by temperature and salinity)

Flow of the warm Gulf Stream into Europe stopped

Heat no longer carried into the area

Sudden and drastic drop in temperatures in the North Atlantic

Ice pack spread rapidly

Further cooling

The circulation of the ocean.

After about 800 years, the volume of cold fresh water decreased -> flow of tropical waters began again -> rapid warming continued.

This event is important for a number of reasons:

1. illustrates interrelationships between the different elements of the climate system.
2. demonstrates that major natural fluctuations in climate have occurred within the current interglacial period.
3. shows how sensitive climate can be (change can occur quickly, in a matter of decades rather than centuries).