Frozen Library Stores Ancient Ice Blocks, Holds the Secrets of Prehistoric Climate Change

How does the air breathed by ancient people differ from the one we have today? In Copenhagen, Denmark, a giant freezer holds the answers as it stores blocks of ice with memories of the atmosphere thousands of years ago.

Coolest Library on Earth

The Ice Core Repository is a vast archive finished in January 2020 which houses 15 miles (25 kilometers) of ice blocks. The materials were gathered from the polar region, mainly from Greenland, including the six deep ice cores from EGRIP, NEEM, NGRIP, GRIP, DYE-3, and Camp Century.

The repository is one of the biggest in the world, holding 40,000 blocks of ice stacked in large boxes on long rows of shelves. According to glaciology professor Jorgen Peder Steffensen from the University of Copenhagen, this archive stores prehistoric climate change, a collection of man's activities in the past 10,000 years.

The frozen samples inside the facility are unique since they comprise compressed snow instead of icy water. All the airspace between the snowflakes is trapped as bubbles inside, while the air inside these bubbles is the same age as the ice.

The antechamber of the repository is the same as the library's reading room. It is where scientists examine the ice withdrawn from the main library or storage room. However, this must be done very quickly. The temperature in the antechamber is maintained at -0.4 degrees Fahrenheit (-18 degrees Celsius), while the storage room is kept at -22 degrees Fahrenheit (-30 degrees Celsius).

In the 1960s, experts brought the first ice cores to Denmark from Camp Century, a secret US military base on Greenland. Last summer, the most recent samples were obtained from the bedrock in eastern Greenland at a depth of 1.6 miles (2.6 kilometers). They contain extracts from 120,000 years ago during the most recent interglacial era when air temperatures in Greenland were 5C higher than today.

Copenhagen's Ice Core Repository is separate from the Ice Memory Foundation, which has gathered ice cores from 20 regions worldwide. The foundation preserves the ice cores for future researchers at the French-Italian Concordia research station in Antarctica before they get lost forever due to climate change.

Secrets from the Past

The Earth has been much warmer than today, but that was before humans existed. The recently acquired ice helps the experts understand the rising sea levels, which can only be partially explained by the shrinking ice cap.

The atmospheric changes can also be explained by ice streams or the fast-moving ice on the ice sheet, which melts alarmingly. Understanding ice streams allows researchers to have better insights into the amount of contribution to rising sea levels in the future. Scientists hope to predict rising sea levels in 100 years with a smaller margin of error.

Ice cores were an essential tool in determining the state of the Earth's atmosphere before humans introduced air pollution. With these ice cores, experts can map out how greenhouse gases, carbon dioxide, and methane change over time. They also show the impact of the burning of fossil fuels in the modern era.