How Glaciers Store Water

A glacier is a huge mass of ice that forms on land and moves slowly over time. Glaciers are important because they store the largest share of Earth's freshwater. About 69% of all freshwater on our planet is frozen in glaciers and ice sheets. This means that most of the water we could drink is locked up as ice, which explains why so little freshwater is available for people, animals, and plants to use.

Glaciers form over many years when snow falls and does not melt completely. Each winter, new snow piles on top of old snow. The weight of the new snow presses down on the layers below. Over time, this pressure squeezes the snow together and turns it into solid ice. Think of it like making a snowball—when you pack snow tightly in your hands, it becomes hard and dense. In a glacier, this process happens on a much larger scale and takes hundreds or even thousands of years.

Freshwater is water that contains very little salt and is safe for drinking, farming, and other uses. Most of Earth's water is saltwater in the oceans, which people cannot drink. Only about 3% of Earth's water is freshwater, and most of that freshwater is frozen in glaciers. Ice sheets are the largest type of glacier, covering huge areas of land in polar regions like Antarctica and Greenland. These ice sheets can be several miles thick.

Glaciers are found in two main places: polar regions near the North and South Poles, and high mountains around the world. Even in warmer countries, glaciers exist on tall mountains where temperatures stay below freezing. Mountain glaciers are smaller than ice sheets but still hold large amounts of frozen water.

Understanding where Earth's freshwater is stored helps us see why water is such a precious resource. Since most freshwater is frozen in glaciers, only a small amount is available as liquid water in lakes, rivers, and underground. This is why protecting our water sources matters so much.

Interesting Fact: If all the ice in glaciers and ice sheets melted, sea levels around the world would rise by about 230 feet—that's taller than a 20-story building!