N. Greenland Eemian Project Hits Bedrock - Ice Core Will Likely Be Best Record Yet Of 130,000 BPE

[hatrack]

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That’s why an announcement out of northern Greenland last week could be so important. Last Tuesday, after three years of careful drilling through the island’s thick layer of ice, a team of scientists working on the North Greenland Eemian Ice Drilling project, or NEEM, hit bedrock, exactly 2537.36 meters (nearly 8,325 ft.) below the surface. The ice they dredged up from that depth dates to the Eemian period, about 130,000 years ago, a time when the planet had emerged from a long period of glaciation into an interglacial period like we’re in today — except that the temperature was two to three degrees Celsius, or up to five degrees Fahrenheit, warmer than it is at present, and sea levels were 13-20 feet higher. The warming during the Eemian was triggered by a shift in the alignment of the Earth and Sun that brought more direct sunshine to the Arctic than we see now. But figuring out how the climate responded to warming, even if the trigger is different now, could prove crucial in projecting what will go on in the next century or so.

With this ancient ice in hand, that’s just what the NEEM researchers are planning to do. The ice was originally laid down as snowflakes, which were eventually compressed into solid ice by later snowfalls, accumulating over the years. Tiny air bubbles trapped inside preserve the atmosphere from the time of the original snowfall, so scientists can measure the amount of CO2 and other gases that were present. The ice itself, meanwhile, contains a mix of different oxygen isotopes that depend on the atmosphere’s temperature at the time. Beyond that, trapped plant material, such as pollen grains, can help the scientists figure out how green Greenland really was.

Here’s how Richard Alley, a Penn State ice core expert, put it to me in an email (I love how he calls the Eemian “Eem”; it’s so familiar to him that he uses a nickname): "The Eem is a time when the orbits brought more summer sunshine to the far north than occurred a few thousand years ago, so the Eem gives us a view of what a warmer climate might be like (how did snowfall, and dust transport, and other things, change as the temperature changed, for example?), and what it might have meant to the Greenland ice sheet (how much melting from the warmth, how big was the ice sheet?). The experiment is not perfect — changing CO2 and changing the summer sunshine are not exactly the same thing — but the experiment is certainly instructive, so we can learn a lot from it."

This isn’t the first Greenland project that has tapped into the Eemian, but Alley says that ice cores from other sites haven’t gotten a clean record; for whatever geological reason, the ice has been disturbed and mixed in with other time periods. At the NEEM location, the ice is relatively pristine, making good information easier to extract.

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http://climatecentral.org/breaking/blog/greenland_ice_core_drilling_project_reaches_milestone

[Hissyspit]

1. 8,325 - three times the length/height of the Burj Dubai