Ice core drilling effort should help assess abrupt climate change risks

University of Colorado at Boulder: An international science team involving the University of Colorado at Boulder that is working on the North Greenland Eemian Ice Drilling project hit bedrock July 27 after two summers of work, drilling down more than 1.5 miles in an effort to help assess the risks of abrupt future climate change on Earth.

Led by Denmark and the United States, the team recovered ice from the Eemian interglacial period from about 115,000 to 130,000 years ago, a time when temperatures were 3.6 to 5.4 degrees Fahrenheit above today's temperatures. During the Eemian -- the most recent interglacial period on Earth -- there was substantially less ice on Greenland, and sea levels were more than 15 feet higher than today.

While three previous ice cores drilled in Greenland in the last 20 years recovered ice from the Eemian, the deepest layers were compressed and folded, making the data difficult to interpret. The new effort, known as NEEM, has allowed researchers to obtain thicker, more intact annual ice layers near the bottom of the core that are expected to contain crucial information about how Earth's climate functions, said CU-Boulder Professor Jim White, lead U.S. investigator on the project.

…Annual ice layers formed over millennia in Greenland by compressed snow reveal information on past temperatures and precipitation levels, as well as the contents of ancient atmospheres, said White. Ice cores from previous drilling efforts revealed temperature spikes of more than 20 degrees Fahrenheit in just 50 years in the Northern Hemisphere.

White said the new NEEM ice cores will more accurately portray past changes in temperatures and greenhouse gas concentrations in the Eemian, making it the best analogue for future climate change on Earth. An international study released by the National Oceanic and Atmospheric Administration last week showed the first decade of the 21st century was the warmest on record for the planet….

An international drilling team involving CU-Boulder has hit bedrock 1.5 miles below the icy surface of Greenland, pulling up deep ice cores from the last interglacial period that should help climate scientists assess the risks of abrupt climate change on a warming Earth. Image courtesy NEEM ice core drilling project