Melting Ice Sheets

It's widely known all throughout the world that ice sheets, or large masses of ice that cover areas of ice over 50,000 square kilometers, are rapidly melting. There are currently only two technically classified ice sheets, known as the Antarctic and Greenland Ice Sheets. The Antarctic Ice Sheet is the single largest mass of ice on the planet, covering around 14 million square kilometers. To put this into perspective, about 90% of the freshwater on Earth's surface is in the Antarctic Ice Sheet. The Greenland Ice Sheet covers roughly 82% of the surface of Greenland. If the Greenland Ice Sheet melted completely it would cause sea levels to rise about twenty three feet. As you can see, the melting of either one or both of these ice sheets would cause massive amounts of freshwater to mix with saltwater. Steps need to be taken to help slow down the melting of these ice sheets. The inevitable fact of having more freshwater in oceans, will cause changes in climate and in the levels of oceans.

In the past few years, people thought the major cause of ice melting was due to the warming temperatures on Earth. More recent studies show that the leading cause of ice melting is due to the warming of water temperatures in oceans. Warmer waters, caused by global warming, trigger the breakup of ice shelves and faster flow of ice shelves. In Greenland there

is an ice shelf known as the Jakobshavn Glacier that has retreated more than five miles since the early 90's. To your right is a picture showing the change in the Jakobshavn Glacier. This flow of ice has increased the rate of sea level rise by 0.06 millimeters per year. It is important to realize that what seems to be a small change, can effect the entire world by raising the whole sea level. Since the melting of ice is caused by global warming, it would definitely be useful to reduce the amount of green house gases that we emit. One of the most common ways known to reduce green house gases is to reduce carbon dioxide emissions and a good way to do this is reduce your use of cars.

It wasn't until about six years ago that there was even a way to accurately measure the size of ice sheets. Through advances in remote sensing, instruments on aircraft, and instruments on satellites, scientists can make accurate assumptions about how much and how fast ice sheets are melting. Most recently, satellite lasers have been used to produce the most comprehensive picture of melting ice sheets, shown at left. This picture shows us that the most severe melting is occurring in the western Antarctic sheet and southern Greenland sheet. It is apparent, by looking at the picture, that we need to slow or stop ice melting in the ice sheets. If ice melting continues to occur, the rise in sea levels could potentially wipe out coastal cities. Also a rise in sea levels means a rise in the amount of freshwater in the oceans. With less of a concentration of saltwater, oceans could be altered forever. The salt in oceans plays a key role in how the gulf stream works and alters the climate. With less salt in the water, the gulf stream would change and wouldn't warm the area around the gulf stream. It is important to slow ice melting so this does not occur.

By viewing the picture made by satellite images, one can tell that a significantly large amount of the Antarctica ice sheet is melting and basically all of the Greenland ice sheet has some melting. In a recent study, scientists tried to find out why most of the Greenland Ice Sheet was melting. They found that ice sheet melting is caused by more than warmer air and water temperature. The scientists found that melt water that flows through the ice causes the interior of the ice to melt. Melt water not only causes ice to melt, it causes ice to melt at rates close to a decade instead of a century. With the knowledge of all the ways ice melting can effect the planet, I hope you believe in the fact that it needs to be slowed or stopped.