Drilling Back to the Future: Climate Clues from Ancient Ice on Greenland

In July of 2009, Climate Central senior research scientist Heidi Cullen traveled to Greenland with a production team from StormCenter Communications to visit the North Greenland Eemian Ice Drilling Project, or NEEM. Scientists from 14 nations gather together each summer in northern Greenland, where they work to drill a core of solid ice, looking into the past for clues to future climate change.

The NEEM scientists are focused on a period known as the Eemian, which began about 130,000 years ago and lasted about 10,000 years. During the Eemian, temperatures were between 5 and 9 degrees F warmer than today, and global sea level was 13 to 20 feet higher. Under many climate change scenarios, global temperatures are projected to warm a similar amount this century, so understanding the climate of the Eemian could teach us more about the potential effects of warming today.

To study past climate, the scientists rely, in part, on information trapped inside tiny bubbles in the ice. These bubbles contain traces of the ancient atmosphere. In an underground trench carved from the snow, the scientists work in a makeshift laboratory to extract information from the ice. To do so, they use an analytical system called "continuous flow analysis", where they take a section of the ice core, and melt it on a hot plate millimeter by millimeter. As the bubbles pop, the data is retrieved.

Other ice core samples are cut, bagged, and shipped to research centers all over the world directly from the NEEM camp. This creates a difficult logistical effort that is made possible by the 109th Airlift Wing of the New York Air Force National Guard. Pilots from the 109th fly specialized planes, called LC-130s, essentially a C-130 aircraft equipped with skis.

The ice cores provide the NEEM scientists with priceless information about past climate history. The data from the cores show a strong correlation between carbon dioxide levels and temperature, reinforcing an important theme from climate science: that carbon dioxide causes warming.

Learning about these ancient climates can also tell us more about future sea level rise. The Greenland ice sheet contains enough ice to raise global sea level by 23 feet. By using Satellite data from the NASA Grace Mission, scientists have been able to measure Greenland's current ice loss. In 2007, Greenland shed 340 billion tons of ice — a loss roughly the same as draining an extra San Francisco Bay's worth of water into the ocean every week for a year.

By the end of the 2010 season, when the scientists drill down to the Eemian period, they will get a much better sense of just how much Greenland's ice melted during the last major warm period, when global sea level rose 13 to 20 feet higher than it is today.

For more about NEEM and the stories of the people who make it possible, watch Ice Cores and Climate, The Pilots of the 109th Airlift Wing, or Life on the Greenland Ice Sheet, three short videos originally broadcast on The Weather Channel.