Glacier – ice mountain
Glaciers are flowing masses of ice, created by years of snowfall and cold local temperatures. Thousands of years ago, large parts of the world were covered with glaciers. Today glaciers exist all over the world. Greenland and Antarctica are covered by thick sheets of glacier ice. There are smaller glaciers in the Rocky Mountains of North America, in the European Alps, in the Andes of South America, and even at mountainous points along the equator.
Glacier ice today stores about three fourths of all the freshwater in the world.
Continental glaciers begin with a decrease in temperature and an accumulation of snow, over tens of thousands of years.
The snow is compacted by its own weight. Eventually, the snow at the deepest level begins to form ice.
Mountain glaciers begin with a cold temperature and an accumulation of precipitation at the highest elevations.
Glaciers have been melting worldwide since the beginning of the Industrial Revolution in the mid-nineteenth century. Water from melting glaciers is a significant input to rising sea levels worldwide. This would result in flooding of every continent’s coastlines. Global average sea level has been rising at about 3 mm per year and the speed is rising.
An iceberg is a large mass of free-floating ice that has broken away from a glacier. Icebergs wander over the ocean surface until they melt. They consist of freshwater ice, pieces of debris, and trapped bubbles of air. They can be blue, green, and white and come in a variety of shapes and sizes. Only a small part of the iceberg is visible above the surface of the sea.
An iceberg struck and sank the Titanic on April 14, 1912, when the great ship was on her maiden voyage. More than 1,500 people lost their lives in that disaster.