NSFPLR-NERC: THwaites Offshore Research (THOR)

There is a consensus that incursion of warm water across the continental shelf is the main driver of contemporary retreat of Thwaites Glacier, which presents the greatest risk of future rapid global sea-level rise. Uncertainty in model projections of the future of Thwaites Glacier can be significantly reduced by a range of investigations seaward of the current grounding line, including extracting a record of decadal to millennial variations in warm water incursion and the history of pre-satellite era grounding line migration, and constraining the bathymetric pathways that control the flow of warm water to the grounding line. Sedimentary records and glacial landforms preserved on the seafloor will allow reconstruction of changes in drivers and the glacier's response to them over a range of timescales, thus providing reference data that can be used to initiate and evaluate the reliability of models. Such data will also provide insights on the influence of poorly understood processes on marine ice sheet dynamics. The proposed project includes an integrated suite of marine and sub-ice shelf research activities aimed at
establishing boundary conditions seaward of the Thwaites Glacier grounding line, obtaining records of the external drivers of change, improving knowledge of processes leading to collapse of Thwaites Glacier, and determining the history of past change in grounding line migration and conditions at the glacier base. These objectives will be achieved through high-resolution geophysical surveys of the seafloor and analysis of sediments collected in sediment cores from the inner shelf seaward of the Thwaites Glacier grounding line using ship-based equipment, and also from beneath the ice shelf using a corer deployed through the ice shelf via hot water drill holes.

This project will use a suite of marine geological and geophysical data from seaward of the modern grounding line, to derive records of drivers and pre-satellite era retreat history, and determine key boundary conditions that control Thwaites Glacier retreat. The data will be used to address three pairs of hypotheses about the behavior of Thwaites Glacier. The first pair of hypotheses address the impact of warm-water incursions on glacial stability, both the modern pathways for such incursions and the 20th century history of warm-water initiated retreats. The second pair of hypotheses address the role of subglacial meltwater on Thwaites Glacier stability, using a comparison of modern sediment flux rates to those recorded in cores to test the episodic nature of subglacial meltwater output, and of its influence on glacial stability. Finally, the third pair of hypotheses address the role the nature and topography of the bed and ice shelf pinning points have on stabilizing the grounding line.

We will apply for a PolarTrek teacher to participate on cruise 1 (2018/19), who will link up with several schools in the UK and the US and the general public using blogs, e-mail question and answer sessions, curriculum development, and other activities before, during, and after the cruise. Several of our team members have successfully hosted such teachers in the past. Additional K-12 outreach will include visits to schools by individual PIs and an Earth2class (https://earth2class.org) teacher training workshop at LDEO-Columbia University with Co-PI Nitsche's involvement, where K-12 science teachers will be updated on project results and develop curriculum materials. Co-PI Minzoni will build static displays on Antarctic climate change for the Alabama Museum of Natural History, and participate in the "Natural Science with an Expert" program, which reaches hundreds of K-12 students from local schools each semester. UK Co-PIs Hogan and Smith and the BAS post-doc will work with the BAS Comms team to promote the shipborne research and outcomes, as part of their educational strategy, with local schools and national schools through BAS's digital channels. Examples would include blogs, images of 'science in action', video clips and on the BAS website (on average 65,000 unique visitors per month) and social media via Facebook (16,000 followers) and Twitter (19,000 followers).

The UK component of the project will fund development of "Ice Flows," a computer game about ice flow in Antarctica underpinned by real data and ice-sheet physics (http://www.iceflowsgame.com). Together with Dr. A. Le Brocq, and in collaboration with professional game developers (Inhouse Visuals), we will build upon a successful existing app (>10,000 individual players in 2016) to construct new gaming elements related to our proposal's science objectives. Specifically, players will learn, through play, about the techniques of under-ice survey in Antarctica, and the forcing that leads to TG change. Linked online content and further development of a teacher mode will allow the app to be used as an educational aid in classrooms at a variety of educational levels.

Public Engagement with Science: Field activities are rich opportunities to engage, excite and educate the public about real-time science discoveries. In support of advancing understanding of Thwaites Glacier through field activities, we will provide a variety of real-time outreach communications to inform and directly engage stakeholders, educators, media, and the general public about Thwaites Glacier change, specifically how the paleo-record helps us understand the future of Thwaites Glacier. Rice University science writer L. Welzenbach will participate onboard cruise 2 to provide direct public outreach throughout the project timeline. As part of cruise 2, the science writer will, for example, write a daily blog, broadcast video of field and laboratory research if sufficient internet bandwidth is available, and conduct media interviews with the scientists. These blogs and videos will be re-packaged by BAS for posting simultaneously on UK digital channels (BAS website, Facebook, Twitter and YouTube). Videos could also be shared with trusted journalists like BBC Online who frequently package up Antarctic footage into digital stories, reaching millions of viewers. Post-field deployment activities will utilize undergraduate students from local institutions (Rice U. and the U. Houston) associated with the grant to work with PIs and the science writer in developing content captured from field activities that can be used for a variety of education and outreach products, for example, museum special exhibit programs, documentary films, and science briefs to help students develop skills in science communication. PI Wellner will continue to give talks to local societies and organizations as well as continue her new column at Forbes.com about energy use and the environment.