The Melting Greenland Ice Sheet

According to a study performed by the National Center for Ecological Analysis and Synthesis (NCEAS) Scientists have warned that by the year 2100, ocean levels may be increasing three times as quickly as they are presently. This may be due to the rapid meltdown of a region of ice known as the Greenland icecap or ice sheet. An ice sheet is an area of land covered with ice.

The ice sheet over Greenland covers an area of 1.8 million square kilometers. It is melting quicker than expected. This is because of surface water finding its way down via fissures to the bedrock. The ice sheet is also less stable.

The melting ice sheet will result in a 9mm sea level rise every year, with a total rise of 1 meter for 100 years. Globally, ocean levels are already rising due to increasing temperatures, as the oceans tend to expand with higher temperatures.

During the ice age, nearly 19,000 years ago, the Laurentide icecap was over much of North America. It was two miles thick in many places but completely melted off 7,000 years ago. This was because the earth had warmed up. Scientists used computer simulations and geological clues to reconstruct this meltdown. They dated fossils and boulders and arrived at the finding that it there were two stages of rapid melting. One was around 8,500 years ago during which time the melting ice sheet caused a sea level rise of 7 meters. The second bout of rapid melting came 7,000 years ago, causing ocean levels to increase by 5 meters.

The ice sheet covering Greenland may also melt off likewise. This may happen in the next 200-300 years. The predicted sea level rise may not be catastrophic, but the increase in sea level will be bigger during the next century. According to a report from the Climate Change UN Intergovernmental Panel, by 2100, the sea level will rise by 10 cm. This may become higher due to the meltdown of the ice sheet covering Greenland.

Scientists do point out that though the Laurentide icecap may have completely vanished, the Greenland icecap remains, suggesting it may be comparatively resistant to warming. They conclude that a sea level rise of 1 meter every 100 years is well within knowledgeable prediction.

It may be noted that if the sea level rises by 1 meter it may submerge up to 2.2 million square km of land area, mainly in Asia. It may also displace 145 million people with a cost of $944 billion.

Source:

http://www.cnn.com/2007/TECH/science/10/23/greenland.melting/index.html