New study suggest that melting Arctic ice can trigger an ice age

[Tsanten Eywa 'eveng]

For 12,900 years ago, it started a so-called "Big Freeze", which lasted 1,200 years.

http://www.dailymail.co.uk/sciencetech/article-2228714/New-model-shows-unprecedented-glacial-meltwaters-cooled-Earths-oceans-bring-big-freeze.html

The planet's last major cold spell 13,000 years ago was caused by a catastrophic deluge of frigid fresh water from north-west Canada into the Arctic ocean, a new study suggests.
Detailed computer simulations show meltwater from the enormous Laurentide Ice Sheet halted the sinking of very dense, saltier, colder water in the North Atlantic.
That stopped the large scale ocean circulation - the so-called thermohaline circulation - that transports heat to Europe and North America, causing the continents to dramatically freeze.

The findings offer a new explanation for the cause of this last big chill, which scientists had thought was caused by freshwater flowing into the Atlantic through Canada's Gulf of St Lawrence.
It led to a cold spell lasting more than 1,000 years known as the Younger Dryas or 'Big Freeze', during which temperatures in parts of the northern hemisphere fell to about 10 degrees C colder than they are today.

'This episode was the last time the Earth underwent a major cooling, so understanding exactly what caused it is very important for understanding how our modern-day climate might change in the future,' said Alan Condron, of the University of Massachusetts Amherst.

The cooling began after Lake Agassiz, at the southern edge of the Laurentide ice sheet covering much of the Canadian Arctic, broke through an ice dam and dumped thousands of cubic kilometers of cold water into the ocean.
Using a high resolution, global, ocean-ice circulation model 10 to 20 times more powerful than previous ones, the researchers compared how meltwater from the two different drainage outlets affected ocean circulation.
The original hypothesis, proposed 1989 by Wally Broecker of Columbia University, suggested that Lake Aggasiz drained into the North Atlantic down the St Lawrence River.