On glaciers and global warming

I just finished reading Bill Bryson's A Walk In the Woods
in preparation for hiking part of the Appalachian Trail next autumn.
It's an excellent book - highly recommended regardless of whether or
not you're planning to hike the AT.
Just wanted to share the following passage with you. I found it
fascinating:

"No one knows much of anything about the earth's many ice
ages - why they came, why they stopped, when they may return. One
interesting theory, given our present-day concerns with global warming,
is that the ice ages were caused not by falling temperatures but by
warming ones. Warm weather would increase precipitation, which would
increase cloud cover, which would lead to less snow melt at higher
elevations. You don't need a great deal of bad weather to get an ice
age. As Gwen Schultz notes in Ice Age Lost, "It is not
necessarily the amount of snow that causes ice sheets, but the fact
that snow, however little, lasts." In terms of precipitation, she
observes, Antarctica "is the driest large area on Earth, drier overall
than any large desert."
Here's another interesting thought. If glaciers started reforming, they
have a great deal more water now to draw on - Hudson Bay, the Great
Lakes, the hundreds of thousands of lakes of Canada, none of which
existed to fuel the last ice sheet - so they would grow very much
quicker. And if they did start to advance again, what exactly would we
do? Blast them with TNT or maybe nuclear warheads? Well, doubtless we
would, but consider this. In 1964, the largest earthquake ever recorded
in North America rocked Alaska with 200,000 megatons of concentrated
might, the equivalent of 2,000 nuclear bombs. Almost 3,000 miles away
in Texas, water sloshed out of swimming pools. A street in Anchorage
fell twenty feet. The quake devastated 24,000 square miles of
wilderness, much of it glaciated. And what effect did all this might
have on Alaska's glaciers? None."

Posted by flow Frazao on December 8, 2003 at 10:11 PM | Permalink