What is the meaning of Rip Van Winkle?
Definition of 'Rip Van Winkle'
1. a person who is oblivious to changes, esp in social attitudes or thought. 2. a person who sleeps a lot. Collins EnglishDictionary.
At the height of the recent glaciation, the ice grew to more than 12,000 feet thick as sheets spread across Canada, Scandinavia, Russia and South America. Corresponding sea levels plunged more than 400 feet, while global temperatures dipped around 10 degrees Fahrenheit on average and up to 40 degrees in some areas ...
How thick was the ice that covered North America?
3 kilometres
Today, about one-tenth of the Earth's land is covered by glacial ice. The Laurentide Ice Sheet was almost 3 kilometers (2 miles) thick and covered North America from the Canadian Arctic all the way to the modern U.S. state of Missouri...
Ice ages: Why North America is key to their coming and goingScientists have long tried to figure out what causes the ebb and flow of ice ages. New data suggests a novel explanation for why the mile-thick blankets of ice retreat so quickly: They become too heavy.
For the last 900,000 years, mile-thick ice sheets have waxed and waned in the Northern Hemisphere with remarkable regularity – building over periods of about 100,000 years and retreating in the space of only a few thousand years, only to repeat the cycle. Now, a team of scientists from Japan, the US, and Switzerland suggests that the North American continent is the breeding ground for these cycles. It's a region where climate and the ice's effect on the Earth's crust play off each other to draw out the length of a glacial cycle triggered by changes in solar radiation that come with changes in Earth's orbit. This feedback between climate and ice becomes most dramatic at the end of the cycle, when an ice sheet that has bulldozed its way too far south and gotten too heavy for its own good meets up with a warming climate. "When the ice sheets get to this huge state, they are very hard to keep that way," says Maureen Raymo, a paleo climatologist at Columbia University's Lamont-Doherty Geophysical Observatory in Palisades, N.Y., and a member of the team conducting the study. Once a change in Earth's orbital characteristics brings on the next warming event, "the whole system just goes into catastrophic collapse,” she explains. “It melts back a little, seas start to flow into the depressed crust, this floats the ice and melts it from below.”LINK
