What do you think of when you hear the word "arctic?" Most likely, a vast sheet of shiny ice comes to mind. Unfortunately, Arctic ice is melting faster than ever before. About 552 billion tons of ice melted in the summer of 2007. This amount of melting ice causes many problems. As one scientist put it, "The Arctic is screaming!"
Scientists use satellites to track the amount of ice that melts each year. One area that they study is called the Greenland Ice Sheet. This area is an enormous body of ice that covers about 80% of Greenland. This ice sheet was created by layers of snow compressing for over one hundred thousand years. It changes color with the seasons. It is a clear, aquamarine color in the winter. When the top ice layer melts, it is pure white in the summer.
The recent increase in the rate of melting ice surprises many scientists. The position of the Greenland Ice Sheet makes it melt more quickly than ice in other areas. The ice sheets and glaciers are melting because of global warming. Global warming is the gradual increase of Earth's surface air temperature. However, even scientists do not agree about the reasons for global warming. It is a big debate in the scientific community.