The GreenDrill project is motivated by a need to understand past and future change in the extent of the Greenland Ice Sheet. The Greenland Ice Sheet (GrIS) holds about 24 feet (7.4 m) of sea level equivalent, yet it remains difficult to predict the rate of melt and possible tipping points in the stability of the ice sheet. In GreenDrill, the team of investigators will sample bedrock from under ice at sites in northern Greenland, analyzing cosmogenic nuclides to determine past periods of ice free conditions. These data will provide better understanding of how this region of the GrIS has responded to warm periods in the past. The team will also use these data in computer models to place results in the context of the entire ice sheet to explore mechanisms and climate forcing driving past periods of ice sheet disintegration, which in turn will inform projections of future ice sheet behavior and sea level rise. In addition to the high relevance of this research to society, the GreenDrill project includes broader impacts such as development of a new television episode called Adventures in Science, educational programs for middle and high school students via the Scientists are Superheroes program, and training for early career postdoctoral scientists, graduate students, and undergraduates. In this project, the investigators will gather new data to test the sensitivity of the northern Greenland Ice Sheet (GrIS) and its potential to contribute to sea level rise in the future. Specifically, data from the GreenDrill project will better constrain the response of the GrIS to past periods of warmth and address the hypothesis that the northern GrIS is more sensitive to Arctic warming than the southern GrIS. The team will drill through the ice at sites in northern Greenland, sample bedrock obtained from those cores, and analyze a suite of cosmogenic nuclides (Beryllium-10, Aluminum-26, Chlorine-36, Carbon-14, and Neon-21) that can act as signatures of changes to the GrIS margin. These data will deliver direct observations of periods when the GrIS was substantially smaller than today and ice sheet margins retreated inland. Results will be incorporated into a numerical ice sheet model with a built-in cosmogenic nuclide module to identify plausible ice sheet histories. The modeling experiments will help understand the mechanisms and climate forcing underlying past periods of ice sheet retreat and help inform predictions of the future. Based on the melting scenarios, a first-order map of sea level rise fingerprints and inundation scenarios for major port cities will be produced.

This collaboration between Schaefer (1933927, lead, Columbia University), Briner (1933938, University at Buffalo), Anandakrishnan (1933802, Pennsylvania State University), and DeConto (1934477, University of Massachusetts) will study the response of the Greenland Ice Sheet (GrIS) to a past period of warmth by testing the hypothesis that the northern part of the GrIS is more sensitive to Arctic warmth than the southern portion of GrIS, and under the potential that GrIS has to contribute to sea-level rise in the future. Researchers will sample bedrock near and under the ice sheet throughout northern Greenland in 2022 - 2025. They plan a transect of drill locations at each of these four sites: Prudhoe Land, Hiawatha Glacier, Victoria Fjord, and Dronning Louise Land. Each transect includes several drill cores and other surface samples from non-ice-covered terrain near the coast toward the ice margin. All samples will be sent back to the home institution for cosmogenic nuclide measurements. The project had planned to start in 2021 but was delayed due to travel restrictions related to COVID-19. In 2022, they conducted a three-week geophysical site survey campaign including reflection seismic imaging and radar reflection imaging to provide further confidence in bed properties and aid in final site selection for larger drilling efforts to take place in 2023 and 2024. In mid-summer 2022, the research team returned to Prudhoe Land sites to perform initial pro-GrIS sample collection using a small Shaw drill. In April of 2023, a team of 12 participants (including a Battelle ARO camp manager and Battelle ARO contracted field guide / bear guard) accessed field sites from Pituffik Space Base using a ski-equiped Basler and a helicopter. After they set up camp, the science team drilled through the ice sheet to sample the underlying bedrock at the Prudhoe Land sites. Participants used the ski-equipped Basler to remove the camp from the ice sheet and return cargo and people to Pituffik SB in mid-June 2023. In May, a research team of two plus a contracted field guide and bear guard will conducted an approximately three-week geophysical site survey campaign including reflection seismic imaging and radar reflection imaging to provide further confidence in bed properties and aid in final site selection for larger drilling efforts to take place at Northeast Greenland sites in 2024. In August 2023, a research team of four performed initial pro-GrIS sample collection using a small Shaw drill at the Dronning Louise Land site. The research team leveraged resource and personnel sharing with the Briner project (NSF grant 2106971). In early April 2024, a team of five individuals consisting of (1) PFS mountaineer (2) ANG officers, (1) CRREL personnel, and (1) licensed science team blaster traveled via Norland Air Twin Otter from Akureyri, Iceland to Danmarkshavn, Greenland. From Danmarkshavn. the team traveled to the NE ASIG site on three different day trips to perform a landing area ground truth (SLACO), to use ground-penetrating radar (GPR) to assess the ski landing area, and to detonate explosives that were left in the field in 2023 as a disposal mechanism. Due to logistical constraints, the GreenDrill team was not able access the NE ASIG Drill site and a new plan was developed. In mid-May 2024, a team of 10 participants (including a Battelle ARO camp manager/mechanic, a Battelle ARO-contracted bear guard and a Battelle-ARO-contracted field guide, three Ice Core Drilling Program (IDP) staff members, two research-team members, one CRREL member and one media personnel) traveled from Kangerlussuaq to EGRIP via NY Air National Guard LC130 aircraft. From EGRIP the team was transported via Kenn Borek Air Twin Otter to the NE Winkie Drill site in Dronning Louise Land. After they set up the camp, the science team was able to complete two weeks of drilling at the NE Winkie Drill site. The CRREL participant used GPR to identify a safe camp area and redeployed after completing the tasking at the end of the camp put in. In mid-June a Kenn Borek Air Basler was contracted to take the Winkie Drill camp personnel and equipment to EGRIP. Once all team members were back at EGRIP an LC130 was used to return all participants and everything back to Kangerlussuaq. In August, a team of four participants traveled to Victoria Fjords, Greenland for additional fieldwork. In late April/early May 2025, a Norland Air Twin Otter will be staged out of Pittufik Space Base. Three to four Inussuk personnel will be provided from Pittufik for day trips to the Prudhoe Land ASIG site to retrieve a cache of gear that was left in the field in 2023. Once at Pittufik, the drums, fuel, and plywood will be absorbed into Battelle ARO inventory or arrangements made for appropriate disposal. Survival bags and shovels will be provided by Inussuk for the day trips.Survival bags and shovels will be provided by Inussuk for the day trips.

Battelle ARO will provide ANG coordination for passengers and cargo (from NY and within Greenland), lodging, shared vehicle use in Kangerlussuaq, aircraft charters, Arctic Truck, PistenBully, traverse equipment, snowmachines and sleds, fuel, ethanol and drilling fluid, camp and safety equipment, Arctic Field Training, mechanic and camp manager staffing, and a contracted field guide and bear guard. the U.S. Ice Drilling Program (IDP) will provide drilling equipment and drillers. All other logistics will be arranged and paid for by the PI from the research grant budget.