Frigid mountain glaciers prevent erosion
Glaciers are well known shapers of the landscape as they advance and recede through the ice ages. In the U.S. we even have Glacier National Park named after the work of glaciers, which carved out huge valleys and lakes and sculpted the dramatic mountains, which have exposed the finest fossilized examples of extremely early life found anywhere on Earth.
As we all know, glaciers are in trouble. At the Montana Park, only 25 glaciers remain in 2010 of an estimated 150 that existed in the mid 1800s, and scientists believe all will disappear by 2030 under current climate change scenarios.
Scientists are now finding that glaciers not only mold the landscape, but can protect it as well from the forces of erosion. In a paper published int he journal Nature this week, University of Arizona geologist Stuart Thomson and colleagues compared two regions of Patagonia, the southernmost range of the South American Andes.
By collecting rock samples from the northern and southern Patagonian regions, they were able to determine that the southern mountain belt had been eroding more slowly over the past 5 million years (the most recent spate of global ice ages), and incidentally, had been growing in width, a tell-tale sign of lowered erosion. Why would this be?
The researchers determined that the major difference in the southern belt was its temperature. It’s a whole lot colder down there, closer to Antarctica. The mountain glaciers have been literally frozen in a block of ice.
As temperatures climb due to global warming, what happens to these glaciers and the landscape they have encapsulated? Will they be suddenly subject to the forces of erosion and change forevermore? What life will be lost, and what new life will adapt to these warmer mountain climes?