The effect of global warming on polar ice caps

The effect of global warming on polar ice caps and sea level 

Overview: Earth's temperature increased half a degree celsius over the last 100 years. It might not seem like much but according to the U.S. Environmental Protection Agency, the sea level has risen 6 to 8 inches (15-20 cm) in the last 100 years. 

Overview of Iceberg: Icebergs are chunks of frozen glaciers that break off from landmasses and fall into the ocean. The rising temperature may cause more icebergs to form by weakening the glaciers, causing more cracks and making ice more likely to break off-as soon as the ice falls into the ocean, the ocean rises a little. 

Polar ice caps: 

The main ice covered landmass is Antarctica at the South Pole and it is about 90 percent of the world's ice. Antarctica is covered with ice an average of 7,000 feet (2,133 meters) thick. If polar ice caps melted, the sea levels around. If all of the Antarctic ice melted, sea levels around the world would rise about 61 meters (200 feet). But the average temperature in Antarctica is -37°C, so the ice there is in no danger of melting. In fact in most parts of the continent it never gets above freezing.

There is a significant amount of ice covering Greenland, which would add another 7 meters (20 feet) to the oceans if it melted. Because Greenland is closer to the equator than Antarctica, the temperatures there are higher, so the ice is more likely to melt.

But there might be a less dramatic reason than polar ice melting for the higher ocean level -- the higher temperature of the water. Water is most dense at 4 degrees Celsius. Above and below this temperature, the density of water decreases (the same weight of water occupies a bigger space). So as the overall temperature of the water increases it naturally expands a little bit making the oceans rise.

In 1995 the Intergovernmental Panel on Climate Change issued a report which contained various projections of the sea level change by the year 2100. They estimate that the sea will rise 50 centimeters (20 inches) with the lowest estimates at 15 centimeters (6 inches) and the highest at 95 centimeters (37 inches). The rise will come from thermal expansion of the ocean and from melting glaciers and ice sheets. Twenty inches is no small amount -- it could have a big effect on coastal cities, especially during storms.