An iceberg in East Greenland breaks from the end of this tidewater glacier.

There are many other types of glaciers. Valley glaciers erode rocks, carving out steep, U‑shaped valleys. Tidewater glaciers flow into the ocean. What happens when a frozen glacier meets ocean water? It can crack and pieces can fall into the ocean. Huge chunks of ice from the glacier then form icebergs.

Piedmont glaciers, like this one in Canada, form wide, round shapes as they spill out onto flat areas.

Glacier 101

Today, there are hundreds of thousands of glaciers worldwide. Some are huge. There are ice sheets that are roughly the size of the U.S. states of Delaware, Maryland, and New Jersey combined! Only two ice sheets exist in the world—in Greenland and in Antarctica.

A lake forms at the terminus of this Icelandic valley glacier.

Piedmont glaciers flow from steep mountain areas onto flat areas. The ice then stretches out into huge crescent shapes. There are tiny glaciers called glacierets. There are mysterious glaciers called rock glaciers. They are made from rock and ice fused together. There are so many other types of glaciers, and no two are alike.

Global Glaciers

Glaciers are found all over the world, and they affect the environment. They make local weather. They build and shape vast landscapes. They provide water and other essential resources. They reveal environmental imbalances. They connect cultures to landscapes. They even provide spiritual fulfillment. To me, that’s what is so powerful about glaciers.

Now, due to climate change, glaciers are melting. This will have a profound effect on Earth. Sea levels will rise. Other water sources may dry up. And many people who live with glaciers may lose part of their way of life.

Muir Glacier, Alaska: August 13, 1941 and August 31, 2004

This winter ice cave formed within an Icelandic glacier.

Every time I explore a glacier, I keep one thing in mind. Ice influences people just as much as we influence ice. And that means, what happens to glaciers, happens to us.

Life at the Extremes

By exploring our planet’s most extreme places, National Geographic is discovering new information about Earth’s climate.