All About Glaciers

Most people don't get to see them often, but glaciers are one of the most important features of the natural landscape. About ten percent of the world's entire landmass is covered in glaciers, and they store about 75 percent of all the freshwater on Earth! According to scientific estimates, the world's sea level would rise over 200 feet if all the glaciers melted. But what are glaciers? How do they form? Where are they now? The ice sheet in Antarctica alone supplies 70 percent of all fresh water, so it's important to know what role these mammoth masses of ice play in the environment.

All About Glaciers: Glacier facts and galleries from the National Snow and Ice Data Center.

Anatomy of a Glacier: From NOVA Online, a production of PBS.

Glaciers and the Glacier Age: Basic question-and-answer page on glaciers and the Ice Age. Illustrated.

Glaciers and Ice Sheets: A variety of information about glacier formation, the polar ice caps, the Antarctic, and more, provided by the University of Michigan.

The Ice Ages: Detailed explanation of ice ages, the Earth's climate cycle, and glaciers past and present.

Though glaciers are incredibly big and heavy, they all begin as piles of mere snowflakes. In a process lasting thousands of years, glaciers form slowly in areas where the snowfall exceeds any melting that happens in warm weather. Gradually, the weight of the fallen snow compresses the whole thing into a mass of ice. Eventually, if the formation starts on a sloping land mass, the whole thing starts to move downhill. Glaciers can vary tremendously in size. Almost the entire surface of Antarctica, 5.4 million square miles, is covered in glaciers! In the Antarctic region, a single glacier 200 feet high may be considered "small." In other places, such as Greenland and British Columbia, glaciers can be the size of a football field or even less. Glaciers can also be much bigger: the Greenland ice sheet covers over 660,000 square miles. Glaciers vary in shape depending on the terrain in which they form; they can be tall and high, such as in the Antarctic, or long and relatively thin, hedged in by mountains to form a sort of ice river.

Glaciers Online: Includes features like an interactive map of states with glaciers, glacier photography, and more information.

Glaciers and Glaciation: More on glacier movement and the factors that affect the size and shape of glaciers.

Illustrated Glossary of Alpine Glacial Landforms: Identifies the different parts of glaciers and their features. Illustrated.

Virtual Tour: Antarctica: A photographic virtual tour of a journey to Antarctica, including information about polar research stations.

Polar Discovery: Thoroughly illustrated information on polar expeditions and research, including expeditions focused on evaluating the health of Greenland's glaciers.

The oldest glaciers in Antarctica likely began to form tens of millions of years ago. Glaciers are mainly found around the world's polar ice caps, and the Antarctic ice shelf holds 90 percent of the world's ice. But glaciers are found elsewhere on Earth where polar conditions prevail. Glaciers are seen around Greenland, Canada, the Scandinavian countries, Russia, and in the state of Alaska. They can be found in the sea or high in the peaks of mountains like the Himalayas and Kilimanjaro. Smaller glaciers are more likely to undergo partial or complete melting, and they provide the majority of glacial runoff that enters the ocean annually. In recent years, scientists have become concerned that larger glaciers may melt due to changes in global climate. For now, though, researchers believe most of the world's largest glaciers are far from melting temperatures. Glaciers are hard for humans to explore, but research stations have been established in the Arctic, and animals like penguins and polar bears depend on glacial ice for their habitat.

Glacier Bay: Information and pictures from the national park in Alaska.

Gift of the Glaciers: On the role of glaciers in the formation of the Great Lakes.

Glaciers at Risk: Information on the importance of glaciers from the World Wildlife Foundation.

Glacier National Park: Home to protected glaciers and stunning examples of natural features carved out and left behind by glaciers.

All About Antarctica: Information on wildlife, environment, geography and more in this glacier-heavy region, provided by the British Antarctic Survey.

Glaciers are a varied, vast, and majestic part of the world's ecosystem. Though most people may never see a glacier with their own eyes, there's no denying how important they are. The world's supply of fresh water depends on the great glaciers, and the features of Earth bear the imprint of glaciers past and present. By learning more about them, we can help ensure that out of sight doesn't mean out of mind.

Glacial Geology at the University of Cincinnati: Includes a stockpile of glacier images.

A Hypertext in Glacial Geology: A thorough introduction for those interested in the technical details of glacier formation.

Glaciers: Then and Now: An activity for children to learn about glaciers.

Arctic Circle: Information, history, culture, and more information about the Arctic Circle, where many glaciers are found.

Antarctic Animals: Photos and information on animals that live on and around glaciers.