when massive continental ice sheets melt what happens to sea level
What is an ice sheet?
Together, the Greenland and Antarctic Ice Sheets contain more than 99 percent of the freshwater ice on Earth. Credit: NSIDC
An ice sheet is a mass of glacial country ice extending more than l,000 square kilometers (twenty,000 square miles). The two ice sheets on World today cover most of Greenland and Antarctica. During the last water ice age, ice sheets likewise covered much of North America and Scandinavia.
Together, the Antarctic and Greenland ice sheets contain more than 99 percent of the freshwater ice on Globe. The Antarctic Water ice Sheet extends nigh 14 1000000 square kilometers (5.4 million foursquare miles), roughly the expanse of the contiguous U.s. and Mexico combined. The Antarctic Ice Sheet contains thirty million cubic kilometers (7.ii million cubic miles) of water ice. The Greenland Water ice Canvas extends nigh 1.vii million square kilometers (656,000 square miles), covering most of the island of Greenland, iii times the size of Texas.
How do ice sheets form?
Ice sheets form in areas where snowfall that falls in winter does non melt entirely over the summer. Over thousands of years, the layers of snowfall pile upwardly into thick masses of ice, growing thicker and denser as the weight of new snow and ice layers compresses the older layers.
Ice sheets are constantly in motility, slowly flowing downhill under their own weight. Nearly the coast, most of the ice moves through relatively fast-moving outlets called ice streams, glaciers, and water ice shelves. Every bit long as an water ice sheet accumulates the same mass of snow as it loses to the sea, it remains stable.
The Antarctic Ice Sheet covers an area larger than the U.South. and Mexico combined. This photo shows Mt. Erebus rising above the water ice-covered continent. Credit: Ted Scambos & Rob Bauer, NSIDC
Why are ice sheets important?
Ice sheets contain enormous quantities of frozen water. If the Greenland Water ice Canvass melted, scientists estimate that bounding main level would rise about half-dozen meters (xx anxiety). If the Antarctic Ice Sheet melted, sea level would rise by virtually sixty meters (200 feet).
The Greenland and Antarctic ice sheets besides influence weather condition and climate. Large high-altitude plateaus on the ice caps modify tempest tracks and create common cold downslope winds close to the ice surface.
In add-on, the layers of ice blanketing Greenland and Antarctica comprise a unique record of Earth's climate history.
Has climatic change started to impact World's ice sheets?
The mass of ice in the Greenland Water ice Sheet has begun to decline. From 1979 to 2006, summertime cook on the ice canvass increased by 30 percent, reaching a new record in 2007. At higher elevations, an increment in winter snowfall accumulation has partially start the melt. However, the decline continues to outpace accumulation because warmer temperatures have led to increased cook and faster glacier movement at the island's edges. To larn more most enquiry on the Greenland Water ice Sheet, visit erstwhile CIRES Managing director Konrad Steffen'southward enquiry Web folio (http://cires1.colorado.edu/scientific discipline/groups/steffen/).
Most of Antarctica has however to see dramatic warming. Notwithstanding, the Antarctic Peninsula, which juts out into warmer waters north of Antarctica, has warmed 2.5 degrees Celsius (4.5 degrees Fahrenheit) since 1950. A big area of the West Antarctic Ice Sheet is besides losing mass, probably because of warmer h2o deep in the bounding main near the Antarctic coast. In East Antarctica, no clear trend has emerged, although some stations appear to be cooling slightly. Overall, scientists believe that Antarctica is starting to lose ice, but so far the process has not become every bit quick or equally widespread every bit in Greenland.
To larn more about how changes in the Antarctic Ice Sheet could touch on sea level, see Country of the Cryosphere: Ice Sheets and State of the Cryosphere: Bounding main Level.
A researcher works with an ice core drill during the 2003 Antarctic Megadunes expedition. Credit: Ted Scambos & Rob Bauer, NSIDC
What can water ice sheets tell united states nigh Earth's climate history?
Scientists excerpt water ice cores from ice sheets and ice caps, studying them to learn virtually past changes in Earth's climate. Ice sheets are made upwardly of layers of snow and water ice that collected over millions of years. Those layers comprise trapped gases, dust, and water molecules that scientists can utilise to study past climates.
How tin can I learn more?
NSIDC Resources
State of the Cryosphere: Ice Sheets. Detect current data on Greenland and Antarctic water ice sheets.
Country of the Cryosphere: Sea Level. Find current data on how ice sheets could touch body of water level.
NSIDC Data
NSIDC distributes scientific data sets related to ice sheets. Come across Avant-garde Data Search to learn more most our data holdings.
Each summer, researchers travel to Swiss Camp on the Greenland Ice Sheet to research climate and water ice sheet dynamics. Credit: John Maurer, NSIDC
Outside Resources
Steffen Research Group: Read about former CIRES Director Konrad Steffen'southward enquiry on the Greenland Water ice Canvass (http://cires1.colorado.edu/science/groups/steffen/).
National Ice Cadre Laboratory: Learn how scientists use ice cores to explore Earth's history (http://icecores.org).
British Antarctic Survey: Find a wide multifariousness of educational and scientific resources almost Antarctica.
Discovering Antarctica: An educational Web site on Antarctica from the British Antarctic Survey and Royal Geographic Society (http://discoveringantarctica.org.uk).
Source: https://nsidc.org/cryosphere/quickfacts/icesheets.html
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