Glacial ice preserves a record of seasonal temperature variations as each yearly layer of snow accumulates and then partially erodes. The accumulating ice also preserves particles from the atmosphere such as pollen. Ice cores extracted so far from Greenland extend at least 100,000 years and from Antarctica more than 800,000.
Glacial ice preserves a record of seasonal temperature variations as each yearly layer of snow accumulates and then partially erodes. The accumulating ice also preserves particles from the atmosphere such as pollen. Ice cores extracted so far from Greenland extend at least 100,000 years and from Antarctica more than 800,000.