What is a Glacier?

A glacier is a thick sheet of compressed snow that moves slowly, due to its own immense size, and generally carves a path through the landscape similar to that of a very slow moving river. Currently about 10% of the worlds surface is made up of glaciers. Most of the glaciers we have today are remnants of the last ice age, when glaciers covered almost 62% of the planet. They are found in the arctic regions and only the highest mountains of the tropics. Glaciers are currently the world's largest fresh water supply.

Glaciers are responsible for many of our natural wonders. The Glacier National Park in Montana, Bryce Canyon in Utah, Yosemite National Park and Lotschental in the Swiss Alps are just a few of the beautiful places that were carved by these massive rivers of ice. Glaciers can also give us hints about the earths past. Scientists excavate "core samples" of the ice. Similar to how scientists can get information from different cross sections of soil and earth these long thin columns of ice are said to show a year by year climate history locked in snow. Scientist slice disks off of the sample and melt the ice, as the ice melts air bubbles frozen inside burst and scientists collect that ancient air. They test it for trace minerals and can get an accurate idea of what the atmosphere was like eons of years ago.

Today glaciers help to illustrate the global climate problems we are experiencing. They are melting at speeds no one has seen before and this causes a rise in ocean levels. At the same time arctic animals are being stranded when winter ice doesn't freeze as solidly or expansively as usual. This is endangered some species while causing a stir in many others. Polar bears for example migrate across a large sheet of ice each winter to find food. Recently the area has been shrinking; this reduces the amount of food available to the bears. Glaciers can show us just how much global warming is affecting our planet.