Ice

When snow falls in Antarctica, it does not melt. Instead, it is buried and compressed into ice by the weight of subsequent snowfalls. The ice sheet that covers Antarctica is built up of hundreds of thousands of years of snowfall. Dust, chemicals, and air bubbles that are trapped during ice formation are like fingerprints that tell us what the earth was like thousands of years ago. Scientists use ice cores to study changes in teh Earth's climate and atmosphere. Most notably, scientists have used data from ice cores to show a correlation helps us to understand global climate change.