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

When a frozen glacier meets ocean water, often the two interact in ways that cause the terminusthe end point of the glacierto calve, or shed, huge chunks of ice directly into the ocean as icebergs.

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

Glacier 101

I soon learned that there are a lot of glaciers to study! Today, there are hundreds of thousands of glaciers worldwide.

Some glaciers are huge. We have ice sheets that are roughly the size of the U.S. states of Delaware, Maryland, and New Jersey combined! Today, only two ice sheets exist in the world—in Greenland and Antarctica. Here are some of my favorite icy landforms.

There are many other types of glaciers. Valley glaciers wind through mountains and erode rocks, carving out steep, U‑shaped valleys. There are tidewater glaciers. These are glaciers that flow into the ocean.

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

Piedmont glaciers flow from steep mountain areas onto flat areas. When the ice moves into the flat area, it stretches out into huge crescent shapes. There are tiny glaciers called glacierets. There are mysterious glaciers called rock glaciers that are made out of 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—in North and South America, Asia, Antarctica, Europe, in the Middle East, Africa, and all along the Equator. Glaciers affect global climate. They make local weather. They build and shape vast landscapes. They provide water and other essential resources. They act as early indicators of environmental imbalances. They also connect cultures to landscapes and even provide spiritual fulfillment.

To me, that’s what’s so powerful about glaciers and why I have dedicated my life to understanding them. They make things that can feel abstract, like climate change, visible.

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

This winter ice cave formed within an Icelandic glacier.

Now, due to climate change, glaciers are melting. This will have a profound affect 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 or their cultural identity.

Every time I explore a glacier, I am reminded that 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.