"At a site called Dome C on the eastern side of the Antarctic continent, the European Project for Ice Coring in the Antarctic (EPICA) recently removed cylinders of ice from a depth of nearly two miles. When the crew returns in December to finish the five-year project and remove the last 328 feet of ice, they will uncover a bedrock layer that has not been touched by light or air in more than 900,000 years.
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Ice coring began in the 1950s, and since then researchers have been removing samples from the Arctic, Antarctic, and any other location where ice accumulates unhindered by melting. A trove of information about the atmosphere and environment waits inside, gleaned from the physical properties of the ice itself, and from the antique air bubbles within it. “It is a direct link to the atmosphere,” says Mark Twickler, director of the National Ice Core Laboratory. “With all other ways of getting data, you have a water surface in the way. Even tree rings have some mediation.”
Researchers have discovered several things about the planet through ice coring. We know that for the last 800,000 years or so, the Earth’s climate has shifted back and forth between ice age conditions and warm, inter-glacial periods, such as the one we’re in right now. Dust in the ice hints at events that influenced climate, such as volcanic eruption and the circulatory power of the Earth’s winds. Researchers are also able to watch the ebb and flow of elements through the environment. Lead levels in the ice increased measurably in the layers corresponding to the introduction of leaded gasoline, and decreased just as sharply in layers corresponding to its removal from the market.
Ice coring allows scientists to gain perspective on our atmosphere and greenhouse gases. “Maybe the most important thing we can see in respect to human activity,
we can show the atmospheric composition we have now is really unlike anything we’ve had for the last 100,000 years,” says Kurt Cuffey, an earth sciences professor at the University of California, Berkeley. “Fossil-fuel burning and agricultural practices have all had an effect. Right now, atmospheric levels of carbon dioxide (CO2) are about 30 percent higher than their pre-industrial levels.”
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