The Hot Zone

Hitting bedrock

Posted by Alison Hawkes on August 4, 2010
Category : Climates of the Past

Ever heard of the Eemian period? It was the previous interglacial period, starting about 130,000 years ago, and was marked by a climate similar to what we might expect under today’s climate change. The sea level was 16 feet higher and the temperatures about 5 degrees F warmer than today.

That’s why scientists like the Eemian. So much so that they’ve put five years effort into drilling a 8,300 foot hole in Greenland’s thick glacial ice to study the Eemian climate. Last week a jubilant North Greeland Eemian Ice Drilling project (NEEM) hit bedrock, in so doing reaching material that has not seen the light of day in hundreds of thousands of years.

Professor Dorthe Dahl-Jensen with the last ice core drilled. Photo courtesy of the Center for Ice and Climate.

Core samples of ice will be analyzed for DNA, dust, and pollen residues to help scientists reconstruct the plant communities and atmospheric conditions of the time, including air moisture content and the concentrations of greenhouse gases. Previous ice cores from Greenland have revealed information about the last ice age into today’s warming period, but this project went much deeper.

Scientists picked the site on Greenland for the project because radar measurements showed the Eemian ice layers below to be thicker and more intact, a boon towards obtaining accurate information. At the time of the Eemian, the ice sheet was much smaller and spots like this were open to the air.

Some 300 ice core researchers from 14 nations, including the U.S., camped out on the frigid site under a main dom with ancillary tents. Laboratories were stationed in deep trenches covered with wooden roofs and topped with snow — a kind of modern day igloo construction.

The NEEM camp in Greeland

Incidentally, Denmark’s  Center for Ice and Climate, which hosted the NEEM project, came up with the idea of studying past climates through ice drilling in the early 1950s. Scientist Willi Dansgaard connected the dots between measuring heavy oxygen isotopes in precipitation with localized temperature.

The discovery went on to launch an entire branch of climate physics where climate change from hundreds of thousands of years ago could be reconstructed. Good news that ice core drilling is getting deeper — we need it now more than ever.

For some cool videos of the drilling, check this out.

-Alison Hawkes

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