Climate change is one of the big news stories and world concerns, with scientists working to understand how much and how fast the world is changing. One of the key tools turns out to be the world's largest collection of ice samples, housed in giant freezers in Copenhagen.
The Ice Core Archive, managed by the University of Copenhagen, has over 25 kilometers of ice cores, drilled primarily in Greenland. That amounts to about 40,000 blocks of ice. The core samples are important because they're not frozen water; they are composed of compressed snow, with air trapped in them—air that can be as old as 10,000 years.
The ancient samples allow scientists to estimate air quality, temperatures and trends over long periods of time to help them understand the more recent changes that can be measured more directly.
The archive was first started in the 1960s with ice cores drilled from a then-secret U.S. military base, Camp Century, on Greenland. The most recent, and deepest, cores were collected last summer at a depth of 2.6 kilometers, where the drills reached bedrock under the ice. They are stored at -30° Celsius.
Image: Prof. Jørgen Peder Steffensen, manager of the Ice Core Archive