Understanding the likely mass balance of the Antarctic Ice Sheet in coming decades is critical to sea-level rise forecasting and the needed societal adaptions. As the ice sheet loses mass at accelerating rates, sections grounded deep beneath sea level are poised to enter a regime of irreversible rapid retreat. Most important of these is the Amundsen Sea Embayment where ocean forcing has triggered widespread changes. To project the ice sheet losses in the future we need to integrate knowledge of past ice sheet changes (marine geoscience methods) with observations (multiple geophysical observations). In turn, this better understanding leads to better modeling and projections of future changes. We welcome observational studies from both onshore and offshore realms, in present and recent past timeframes, that explore and constrain the processes affecting change.