Freeze Frames

Test your knowledge of the many varieties of frozen water and how these icy realms are connected to climate change.

More Info / References

National Snow and Ice Data Center

Extreme Ice Survey

United States Geological Survey

World Glacier Monitoring Service

"Closing the sea level rise budget with altimetry, Argo, and GRACE," Eric W. Leuliette & Laury Miller, Geophys. Res. Lett., Vol. 36, L04608 (2009).

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1. GLOBAL SHRINKING

During the last ice age, glaciers covered almost one-third of all the land. What percentage of the land is covered by glacial ice today?

Ten to 11 percent of the land is covered by ice today. The vast majority of Earth's ice is found in Antarctica. It has an ice sheet more than 1.8 kilometers (1.1 miles) thick on average, and can be more than 4 kilometers (2.5 miles) thick in some places.
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2. ALONE IN THE ZONE

Which is the only continent on Earth with currently no glaciers?

There are no glaciers on mainland Australia today. However, during the last glacial ice age, which ended 10,000 years ago, Mount Kosciuszko had a small glacier and Tasmania had many glaciers. The South Island of New Zealand still has thousands of glaciers.
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3. COLD STORAGE

Roughly what proportion of the world's fresh water is stored in glaciers and ice caps?

The salty ocean contains more than 97 percent of all the water on Earth, which means that fresh water is relatively scarce. About 70 percent of Earth's fresh water is held in ice caps and glaciers. The rest of the planet's fresh water resides in lakes (27 percent), swamps (3 percent) and rivers (less than 1 percent).
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4. THE BIG PICTURE

Where do the really massive icebergs come from?

Antarctica is a continental land mass surrounded by ice shelves that flow into the ocean. Although icebergs around the world come in different shapes and sizes, tabular icebergs (large flat-topped ice masses) calve off Antarctic ice shelves in the Southern Ocean and are carried away by winds and currents. Many of these are massive in size, up to 80 kilometers (50 miles) long.
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5. TROPICAL CHILL

Today glaciers exist only in the higher latitudes; there are no glaciers in Earth's tropics.

Because glaciers are made of ice, they are normally associated with cold regions such as Iceland, Canada and Alaska, but tropical glaciers also exist in Earth's equatorial mountain ranges where the elevation is high enough and cold enough for ice accumulation. Tropical glaciers can be found at the tops of mountains in Colombia, Venezuela, Ecuador, Peru, Bolivia, East Africa and Indonesia.
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6. MELTDOWN

Which of the following is losing the most ice every year?

Ice sheets are large glaciers that cover much of Greenland and Antarctica. Mountain glaciers, smaller than ice sheets, flow from high alpine areas. Even though Antarctica holds the majority of Earth's ice, Greenland, which contains only 10 percent, loses the most ice every year. If all 2.9 million cubic kilometers (0.7 million cubic miles) of Greenland's ice sheet were to melt, it would cause sea level to rise by 7.2 meters (23.6 feet).
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7. LAND OF PLENTY

There are no glaciers in the lower 48 United States.

California, Colorado, Montana, Oregon, Utah, Wyoming and Washington State all have glaciers. Emmons Glacier in Washington State is the largest, with an area of 11 square kilometers (4.2 square miles). Glacier National Park in Montana has 26 named glaciers, which are all shrinking in size. Alaska, not part of the lower 48, has tens of thousands of glaciers.
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8. COLD COMPANY

Do icebergs contribute to sea level rise?

No, sea level does not rise when sea ice melts. Icebergs and frozen seawater do melt with warming temperatures but do not cause sea level to rise because they are already in the water. The volume of water they displace as ice is the same as the volume of water they add to the ocean when they melt.
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9. GRAND TOTAL

In the last 24 years of data, roughly how much ice has been lost from all of the mountain glaciers in the world plus the Greenland and Antarctic ice sheets combined?

Roughly 12.4 trillion tons of land-based ice has been lost over the most recent 24 years of data, worldwide (1994-2017). Including all forms of ice everywhere, Earth has lost 28 trillion tons of ice during that same period. If all of the world's land-based ice melted, global sea levels would rise by about 66 meters (216 feet).
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10. ON THE RETREAT

How much ice, on average, is being lost each year from all the mountain glaciers around the world combined?

At high elevations, snow builds up to form glaciers, which flow downhill, extend into warm areas and melt. An "equilibrium line" separates areas that experience melt in summer from areas that stay ice-covered all year. If more ice melts than accumulates, the glacier retreats. Over the period 2006-2016, seventy-three billion tons of ice from Alaska and 197 billion tons from other mountain glaciers around the world were lost, annually.