How climate is recorded in ice
Glacial ice records the climate of past ages. The composition of the ice itself and of the air bubbles and dust trapped in it record changes in temperature, humidity, atmospheric circulation, volcanic activity, extent of sea ice, and even atmospheric pollution by human activity. The upper layers of ice cores are dated by counting the annual dark and light layers, which reflect seasonal variations in atmospheric dust. Deep layers are compressed and deformed, making the climate record less distinct.
Each year, as snow is buried, it compacts and re-crystallizes into layers of ice. Some of the air between the snowflakes is trapped as bubbles in the ice.
Topic: Earth Science
Subtopic: Climate/Climate Change
Keywords: Climatic changes--Observations, Climatology, Glaciers, Greenland, Ice, Ice cores, Paleoclimatology, Volcanic ash, tuff, etc., Volcanoes
Three 1-meter lengths from a core that penetrated through the entire 3,022-meter-thick Greenland Ice Sheet.
Atop the Greenland Ice Cap, glaciologists have drilled through 3,000 meters of accumulated ice, all the way to bedrock.
The amount of carbon dioxide (CO2) in the atmosphere is related to global temperature: as the Earth warms, CO2 increases, and vice versa.