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|
However, the 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.
At the beginning of the Younger Dryas, the global average temperature fell rapidly by about 2°C in under 50 years. In Northern Europe, average surface temperatures dropped by some 5°C. The much larger cooling in Northern Europe has been attributed to a change in the Atlantic Ocean circulation as outlined below.
|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|
After about 1000 years, the volume of cold fresh water decreased -> flow of tropical waters began again -> and rapid warming of global temperatures began. Over a period of 50 years or less the global averatge temperature increased by about 3°C, while temperatures over Northern Europe increased by 7°C.
This event is important for a number of reasons: