Deep core complete
WAIS Divide project finishes five-year effort to retrieve 3,331 meters of ice
Posted January 31, 2011
More than 20 years in the planning.
Storms often prevented planes from arriving for days or more at a time.
In the final weeks, mechanical breakdowns of the drill and the usual weather delays appeared to derail any hopes of reaching the final depth goal for the season of 3,330 meters.
But it happened. It is done. The U.S. Antarctic Program (USAP) has drilled and recovered its longest ice core to date from the polar regions, officially hitting 3,331 meters. It took five years working from a lonely field camp in one of the stormiest regions of the West Antarctic Ice Sheet (WAIS) to extract the ice, which contains clues about Earth’s past climate from the last 100,000 years.
The core — drilled at a location dubbed WAIS Divide, a high point on the ice sheet where the ice begins to flow in different directions, akin to the Continental Divide in the United States — is the second-longest ice core ever recovered anywhere. The Russians have the record for the deepest ice core, which they drilled in the 1990s at Vostok Station in East Antarctica, to a depth of 3,701 meters. The previous U.S. record was in Greenland, when scientists reached 3,053 meters on July 1, 1993.
“Not only is this the deepest ice core ever drilled by the U.S., but the fact that we have reached our target depth for this season means that the project is on track to be able to complete the entire … project schedule,” said Julie Palais, program manager for Antarctic Glaciology in the National Science Foundation’s Office of Polar Programs .
“It is wonderful to see everything coming together so nicely. ... It is gratifying for me as the program manager, but also for everyone who has been involved because I know how much work has gone into making it happen,” Palais added.
For scientists who will spend the next years, if not decades, analyzing various properties of the ice to understand past climatic and environmental conditions, depth is less important than the timescale represented by the core.
“We did not come here to study the climate of Antarctica — we are here because this is where the information is stored,” said Kendrick Taylor , chief scientist of the WAIS Divide program from the Desert Research Institute in Nevada, shortly before the last core came to the surface on Jan. 28, 2011 at 12:24 p.m. (local time).
The last 100,000 years covers the most recent glacial period, when the Earth was cooler, and large ice sheets covered the northern and southern hemispheres. Concentrations of the main greenhouse gas carbon dioxide (CO2) were much lower than today’s high of 390 parts per million.
In fact, based on other ice cores from Antarctica and Greenland, scientists are convinced CO2 levels are the highest they’ve been in at least the last 800,000 years.
Climate scientists are particularly excited about the WAIS Divide ice core because it promises to offer a particularly “high-resolution” record of the past 40,000 years, with thick annual layers akin to tree rings.
“It is the most detailed record from Antarctica covering a long time period,” said Ed Brook , a professor of geosciences at Oregon State University who has several NSF-funded projects for studying the greenhouse gas concentrations in the WAIS Divide core.
Thanks to the region’s high snowfall rate, there is more ice and more air per year in the core than any other previously collected core. That means scientists can analyze the core in detail, in some cases seeing how year-to-year climate changes unfold.