This map shows projected sea-level rise for different regions of the ocean. The scale bar is in centimeters.
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Courtesy of NCAR

Sea-level Rise May Pose Greatest Threat to Northeast U.S., Canada
News story originally written on May 27, 2009

Water from Greenland’s melting ice may cause sea level to rise more in the North Atlantic than anywhere else in the world.

Melting ice sheets cause sea level rise because the water is added to the ocean. But in this case, changes in ocean circulation are causing sea level to rise much faster.

Part of the reason ocean water moves around the ocean basins in this pattern is because the water is salty. Melting ice adds fresh water to the ocean, which could make the currents weaker.

Weaker currents could cause the dense layer of cold water that sits in the deep Atlantic to warm. Since warm water takes up more space than cold water, sea level would rise more than in other places if this water warmed.

To figure out how melting Greenland ice may affect sea level, scientists used a climate model. They tested three possibilities for the future.

First, they used to the model to test what would happen if the amount of ice that melts increases each year just as it has over the past few years. They found that this would cause sea level to rise up to 51 centimeters (20 inches) more than in other places.

Second, they tested what would happen if the amount of ice melt continued to increase, but not quite as fast. They found that this would cause sea level to rise about a foot

Third, the team tested what would happen with only a very small increase in the amount of melt each year. They found that, in that case, sea level wouldn’t rise more than 20 centimeters (8 inches) more than in other places.

Last modified July 31, 2009 by Lisa Gardiner.

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