Skip to main content Skip to Search Box

Definition: icebergs from Environmental History and Global Change: A Dictionary of Environmental History

Large pieces of floating glacier ice (not sea ice) rising more than 5 m above sea level with 80-90% of their mass below water. The Antarctic ice shelves produce large flat icebergs: ones from Greenland are more jagged. Antarctic icebergs rarely get into the shipping lanes to cause hazards to navigation as they lie too far to the N but the Greenland and Alaskan ones do, most famously in the case of the Titanic in 1912.


Summary Article: Iceberg from The Encyclopedia of Tourism and Recreation in Marine Environments

An iceberg is a very large piece of freshwater ice floating in a body of water. Icebergs are formed through the process of calving, when the front edge of a glacier or ice sheet is weakened by wind, water and sun, and a large piece of ice breaks off into the water. The density of an iceberg that has calved from a glacier is determined by the age of the glacial ice from which it came. Older glacial ice is formed from snow under greater pressure, creating denser ice. The density of the ice determines the weight of the iceberg and how much of the iceberg floats above and below the water’s surface.

As an iceberg floats in the ocean, melting occurs above and below the surface of the water. As the iceberg melts it changes in both shape and its centre of gravity. Icebergs are known to roll, flip and break apart, which can be dangerous to any boats nearby because of the resulting wake and/or falling ice. Arctic icebergs vary in size, icebergs larger than a small house being considered true icebergs, while icebergs smaller than a house are called ‘bergy bits’ and icebergs smaller still are called ‘growlers’. In the Antarctic, icebergs can be even larger when they break off the Antarctic Ice Sheet. The average iceberg has a lifespan lasting 2-3 years from the time when it calved from its source.

The bottom of an iceberg is larger than the portion above the water, approximately five-sixths of the volume of an iceberg being below the surface. Icebergs drift on deep water currents, and can be directed by strong winds. Icebergs are common in many countries, normally near the polar regions. In the northern hemisphere, glaciers float from the Arctic Ocean south into the North Atlantic Ocean. There are approximately 15,000 icebergs calving each year in the Arctic, some float south to the area east of Newfoundland, Canada, called Iceberg Alley because of the large numbers of icebergs located there. Icebergs can be a serious hazard to ships travelling within shipping lanes throughout the oceans. Therefore, icebergs are tracked by the Canadian Coast Guard, the US Coast Guard and the International Ice Patrol. The International Ice Patrol was established after the Titanic sunk after hitting a large iceberg in the Atlantic Ocean, in 1912.

Various industries have taken an interest in icebergs over the years, from vodka and glacier water-bottling companies to tour operators. ‘Iceberg cowboys’ is the name given to individuals who travel in small boats to capture icebergs for the beverage producers and other industries. These people are usually former fishermen from Newfoundland who no longer fish the Grand Banks. Icebergs have been noted as an attraction for tourists who enjoy photographing their different shapes and sizes.

Related internet sources

Canadian Ice Service: http://ice-glaces.ec.gc.ca

International Ice Patrol: http://www.uscg.mil/lantarea/iip/home.html

Cory Kulczycki
© CAB International 2008.

Related Credo Articles

Full text Article ICEBERGS
Encyclopedia of the Arctic

An iceberg is a large floating fragment of glacier ice. According to the US Coast Guard, icebergs are at least 15 m in length at the waterline...

Full text Article iceberg
The Macmillan Encyclopedia

A large mass of ice in the sea that has originated on land. Many result from the breaking off, or calving, of ice from glaciers. In the N...

Full text Article Iceberg properties
Ocean

Icebergs consist principally of frozen fresh water, with no salt content. This is because they originate not from seawater but from...

See more from Credo