The World is Changing

by: Robin Cravey

Wed Jan 30, 2008 at 09:48 AM CST

There's an article in the latest Scientific American that suggests that the Antarctic ice sheet could be unstable, threatening to raise sea level worldwide.

It has been known for a while that if the ice sheet melted, it would raise sea level by 200 feet or more. But scientists have predicted that it would take decades or centuries for all that ice to melt. Now, it seems that the ice could simply slide off.

• The land-based ice sheets of Greenland and Antarctica hold enough water to raise global sea level by more than 200 feet.
• A complex "plumbing system" of rivers, lakes and meltwater lies under the ice sheets. That water "greases" the flow of vast streams of ice toward the ocean.
• For millennia, the out going discharge of ice has been balanced by incoming snowfall. But when warming air or surface meltwater further greases the flow or removes its natural impediments, huge quantities of ice lurch seaward.

The rise in sea level that could occur if the ice sheets slide into the sea would create the greatest refugee migration in history. It would make the aftermath of Hurricane Katrina look like a picnic. This is a worldwide emergency, and we in Austin must spare no effort to reduce our impact on the climate.

(crossposted at www.robincravey.com)