Freeze Frames
Test your knowledge of the many varieties of frozen water and how these icy realms are connected to climate change.
Congratulations!
You're !
You scored
out of
10.
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.
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.
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).
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.
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.
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).
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.
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.
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).
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.
