Lake Effect Snow and Ice Ages

Not by Fire but by Ice


Updated 26 September 06



Here’s a great analogy by Jim Jenness PhD. 
that illustrates how an ice age begins.


Lake Effect Snow and Ice Ages 

Somebody should slowly and gently tell Al Gore we're in the warming phase 
of an ice age cycle. Exchange of water between the Atlantic and Arctic oceans 
is melting the ice. The Kyoto Accords won't stop the Gulf Stream .

Before discussing the ice age cycle, consider lake effect snow. Residents of 
the Great Lakes area are quite familiar with it. Winter gets a head start when 
cold air comes down from Canada and mixes with moist air over the lakes. 
A lot of snow falls on the shore and nearby inland areas, especially Buffalo  
and its suburbs. Later in the winter, when the Great Lakes freeze over, 
lake effect snows stop.

The Ice Age Cycle:

Warm surface water (the Gulf Stream) goes past the coast of Norway into 
the Arctic Ocean and melts ice. It doesn't raise the sea level; the floating ice 
is part of the ocean. After melting some ice, the water cools. Cold water sinks
to the bottom; a deep sea current takes it out of the Arctic Ocean, under the
Gulf Stream
, and back south to warm up again.

When the ice-free part of the Arctic Ocean becomes large enough, The Mother 
Of All Lake Effect Snows begins.  Heavy snow falls on Greenland , Iceland ,
Lapland, and the Arctic shores of Russia , Alaska , and Canada . Eventually it 
piles up so deep the following summer doesn't melt it all. Year-round snow 
cover advances southward. Piled-up snow compresses under its own weight 
and forms glaciers.

White snow reflects sunlight back into space. Eventually the solar Energy 
reflected by the increasing snow cover becomes greater than the energy gain 
by solar heating on land and sea plus the heating of atmospheric carbon 
dioxide and methane by infrared radiation from the Earth. The next ice age 
is upon us.

As more of the Earth's water is transferred to the glaciers, the sea level goes 
down. The depth of water between Greenland and Norway decreases, 
impeding the exchange of water between the Atlantic and Arctic Oceans .
Eventually the reduced Gulf Stream isn't enough to keep the Arctic Ocean  
warm, and it freezes. The Mother Of All Lake Effect Snows ends. Without
replenishing snow, the glaciers start retreating. Global warming begins again. 
(Our present warming began about 11,000 years ago.)

Maybe increased carbon dioxide will make the Arctic ice melt faster. Maybe 
The Mother Of All Lake Effect Snows will begin before the Arctic Ocean is
completely ice-free. 

Anyhow, Al Gore can't stop the ice age cycle. That would require a greater 
effort than inventing the Internet.

Jim Jenness, PhD

P.S. I'm not smart enough to think this up by myself.  It was first described 
by Maurice Ewing and William L. Donn, SCIENCE 123: 1061-1065 
(June 15, 1956).

Thanks to Capt Jeff Nicholas USN for forwarding this to me.





Order Book l E-Mail Robert l Q & A l Book Reviews l Plant Hardiness Zone Maps l Radio Interviews l Table of Contents l Excerpts l Author Photo l Pacemaker of the Ice Ages l Extent of Previous Glaciation l Crane Buried in Antarctic Ice Sheet l Ice Ages and Magnetic Reversals l Expanding Glaciers