Workshop Report - U.S. Scientific Traverses on the Greenland Ice Sheet: Community Planning Workshop

The Greenland Ice Sheet (GrIS) melt rate, and hence its contribution to sea level rise, are accelerating under ongoing climate change, and the ice sheet and its geologic record hold the clues to modern and future climate and to the evolution of GrIS. Understanding this nexus is an urgent challenge for geoscience and society. However, access to the ice sheet for a broad range of scientific investigations by aircraft has become severely limited, and establishing ground-based access requires significant advance planning. On June 10 and 11, 2021, we led a U.S. science community planning workshop that was co- sponsored by the US Ice Drilling Program and the Summit Science Coordination Office. The goal was to identify and articulate compelling scientific priorities of the U.S. scientific community that would drive long-term planning of potential future scientific traverses on the Greenland Ice Sheet.

In total, 49 scientists registered for the Workshop, 42 from a wide spectrum of US Geoscience institutions, the NSF, the USGS and Polar Field Services, and 7 international colleagues from Australia, China, Denmark, Japan and Norway. The meeting agenda and presentations made by the participants are available on https://icedrill.org/meetings/us-scientific-traverses-gris-planning-workshop . The invited opening remarks by Jen Mercer (NSF) set the tone for a workshop full of excitement, outside- the-box thinking and visionary discussion about future research programs to address Arctic change in a timely way. With the upcoming limited traverses operating in North Greenland related to the NSF- funded ‘GreenDrill’ project in 2023 and 2024 as motivation, the participants engaged in discussions to identify important regions of the ice sheet where a ground-based mobile research traverse platform could enable future national and international science and education projects. After presentations by meeting participants, discussion converged on two regions, the Northwest and the Northeast areas of the Greenland Ice Sheet. The participants were then charged to synthesize the workshop discussions and emerging visions for White Papers on two future Greenland Ice Sheet Scientific Traverse programs, one for the Northwest and one for the Northeast. The two community White Papers that follow articulate community consensus on the most burning questions, forming the core of this report.