Meltwater hypothesis: mainstream explanation for Younger Dryas climate shift. The mainstream explanation involves Lake Agassiz, which was larger than all five modern Great Lakes combined An ice dam failed and drainage re-routed through the Mackenzie River Valley into the Arctic An enormous pulse of cold fresh water flooded into the North Atlantic
The leading mainstream explanation involves Lake Agassiz — an ancient lake larger than all five Great Lakes combined. When an ice dam failed, massive amounts of cold fresh water surged through the Mackenzie River Valley into the North Atlantic. Since fresh water floats atop denser salt water, it essentially stalled the Atlantic conveyor belt, cutting off the hemisphere's primary heat transport. Climate models reproduce the cooling pattern when fed realistic meltwater volumes. However, this mechanism doesn't fully account for the near-total collapse of megafauna and human populations occurring simultaneously — that's where alternative hypotheses come in.
Key Facts
- The mainstream explanation involves Lake Agassiz, which was larger than all five modern Great Lakes combined
- An ice dam failed and drainage re-routed through the Mackenzie River Valley into the Arctic
- An enormous pulse of cold fresh water flooded into the North Atlantic
- Fresh water being lighter than salt water created a lid, stalling the Atlantic conveyor belt
- Without heat transport from ocean circulation, the northern hemisphere lost its main source of warmth
- Ocean sediment cores show the freshwater signal the theory predicts
- Climate models reproduce the cooling pattern when fed realistic meltwater volumes
- However, the hypothesis does not fully explain the near-total collapse of megafauna and Clovis people coincidence
Source: Did a Comet ERASE Human History? by Michael Button