The age of glacial ice varies around the world and by glacier. Some of the glaciers in Antarctica may have ice that is around one million years old, which is the oldest ice on the planet. The oldest ice in the glaciers of Greenland is more than 100,000 years old. Some glaciers have ice that isn't nearly as old. The longest glacier in Alaska, the Bering Glacier, doesn't have ice that is more than 400 years old, for example.