Collaborative Research: Refining Long-term Climate Records from the Renland Ice Cap

Researchers on this project will drill, analyze, and interpret a new ice core from the Renland Ice Cap on the north east coast of Greenland. This is a collaborative venture between scientists from the U.S., Denmark's Center for Ice and Climate at the Univ. of Copenhagen and Germany's Alfred Wegner Institute. U.S. efforts will focus on gas concentrations and gas isotopes (Sowers, Penn State) and ice isotopes (White, U. Colorado). Danish partners will also focus on stable isotopes of ice and gas composition, as well as high-resolution chemistry. German partners will focus on physical properties of the ice, line scanning and dielectric properties to investigate the factors driving snow densification and ice core age model development. Ice cores will be retrieved and processed within this international framework. In order to help guide site selection for the 2015 drill project CReSIS will send a surface radar to Renland for a pre-season survey after training a Danish colleague in Kansas on how to operate the radar system. Renland is an important location for an ice core as it is cold (infrequent melt layers), constrained by topography so that it cannot significantly change in elevation, contains ice from the last glacial period (and possibly the Eemian period), and has not been overrun by the main Greenland ice sheet. The lack of elevation change means that Renland's isotopic temperature and total air content records can be used as climate standards against which to compare other Greenland ice cores. The Renland ice cap is about 400 meters thick so it does not contain brittle ice. These properties will allow significant scientific progress to be made in mapping out and constraining Greenland climatic conditions in general, but especially for the Holocene. The occurrence of brittle ice in other Greenland ice cores has limited our ability to reconstruct high-resolution climate records due to poor core quality. The Renland ice core will provide the means of reconstructing greenhouse gas records, volcanic activity, biomass burning events, as well as key feedback mechanisms such as sea ice extent throughout the Holocene. Primary objectives of this project are: 1) link the recent, rapid warming seen in Greenland over the past decade to the baseline record of the past few centuries, as well as the broader Holocene record; 2) provide high-quality gas records throughout the Holocene from a Greenland core to test current theories about the how early human activity may have impacted the greenhouse gas composition; 3) provide an ultra-high resolution isotopic temperature record that is tightly coupled to sea ice near eastern Greenland, as well as a history of climate in this region hopefully extending back into the last interglacial period. This project will provide important data to inform the public, and policy makers, about the earth's climate and what causes changes in that climate. This project proposes to place both the records of sea ice off eastern Greenland, as well as the climate record, into the context of natural variability, and further understanding of recent rapid changes in Arctic temperatures and sea ice. The project will support graduate and undergraduate students.