Have you ever heard the term glacier? A glacier is a huge mass or river of ice that forms when snow falls and compresses into thick layers of ice. They usually form on or near mountains or at the North or South Pole. Glaciers move at different rates with some moving about 10.5 miles per year, which is equivalent to more than 150 feet per day.
Ice Sheets, Mountain Glaciers, and Other Types of Glaciers
There are many different types of glaciers. Here are a few of the types of glaciers you should know:
Ice sheets are the largest type of glacier on earth.
In the past there were many more ice sheetson our planet, but today they are only found in Antarctica and Greenland. Ice sheets can be over 19,000 square miles in size. That would be about the equivalent of the states of New Jersey and Massachusetts combined! Ice sheets can be very thick as well. The ice sheet on Antarctica is up to 3 miles thick in some areas!
Mountain glaciers form in very cold areas with very high mountains.
The largest mountain glaciers are found in places like Canada, Alaska, the Andes mountains in South America, and the Himalayan mountains in Asia. There are quite a few different types of mountain glaciers. Cirque glaciers form on the sides of mountains and are generally circular in shape. They are usually wider than they are long. As you probably could've guessed, valley glaciers form in the valleys of mountains. They flow down the valley and, unlike cirque glaciers, they are usually longer than they are wide .
Tidewater glaciers are larger valley glaciers that flow all the way down to the sea without melting.
When they arrive at the sea, pieces of the tidewater glaciers break off and these pieces float in the ocean as icebergs.
Glaciers are Important Because They Provide Water and Hydroelectricity
Glaciers are important for life on earth because they provide us with a large source of fresh water for drinking and for watering our crops. Without glaciers, we would not have enough water to drink or grow food. Glaciers also help produce electricity through hydroelectric dams.
Glaciers are Threatened By Increases in Global Climate
We have seen changes in the composition of glaciers over the centuries. In recent centuries, with the Industrial Revolution and increases in the burning of fossil fuels, we have seen a rise in the global temperature. This has contributed to the melting of many glaciers. When glaciers melt more rapidly than expected, it is problematic for human and animal life because the water flows into the oceans and raises the sea level. When the sea levels rise, it covers land on the coasts and we lose important parts of that terrain. When the fresh water that once formed glaciers empties into the sea, it dilutes the concentration of salt in the ocean and this is harmful for many species of sea creatures. These animals are then threatened with extinction.