The study investigates the geometric amplification and suppression of basal melt in West Antarctica's ice shelves, focusing on the Amundsen Sea region. The authors use a high-resolution coupled ice-ocean model to simulate the evolution of ice-shelf geometry and basal melt rates over a 200-year period under various ocean-forcing scenarios. Key findings include: 1. **Geometric Feedbacks**: Changes in ice-shelf geometry significantly impact basal melt rates, with reductions ranging from 75% to 75% near the grounding lines, regardless of far-field forcing. 2. **3D Ocean Circulation**: The reconfiguration of 3D ocean circulation in response to changes in cavity geometry leads to sustained and significant changes in basal melt rates. 3. **Net Ice-Shelf Mass Balance**: These feedbacks have a demonstrable impact on the net ice-shelf mass balance, including grounding-line discharge, over multi-decadal timescales. 4. **Future Projections**: The study highlights the importance of considering these geometric feedbacks in future projections of Antarctic mass loss, alongside changes in ice-shelf melt due to anthropogenic trends in ocean temperature and salinity. 5. **Model Setup and Experiments**: The coupled ice-sheet-ocean model Úa-MITgem is used to simulate the evolution of ice shelves and their response to changing ocean conditions. Experiments with fixed and time-varying ocean forcing conditions are conducted to isolate the effects of geometry and natural variability. 6. **Cavity Transfer Coefficients**: The study introduces cavity transfer coefficients to diagnose the feedbacks between changes in basal melt, ocean boundary conditions, and cavity geometry. These coefficients include the thermal transfer coefficient, momentum transfer coefficient, and outer-cavity transfer coefficient. 7. **Results and Analysis**: The results show that while changes in thermal driving at the ice front have a limited impact on melt rates, the geometrically constrained transport of water masses from the ice front to the interior cavity plays a crucial role in amplifying or damping these changes. 8. **Conclusion**: The study emphasizes the need to incorporate these geometric feedbacks into future climate change projections to better understand and predict the dynamics of West Antarctic ice shelves and their contribution to sea level rise.The study investigates the geometric amplification and suppression of basal melt in West Antarctica's ice shelves, focusing on the Amundsen Sea region. The authors use a high-resolution coupled ice-ocean model to simulate the evolution of ice-shelf geometry and basal melt rates over a 200-year period under various ocean-forcing scenarios. Key findings include: 1. **Geometric Feedbacks**: Changes in ice-shelf geometry significantly impact basal melt rates, with reductions ranging from 75% to 75% near the grounding lines, regardless of far-field forcing. 2. **3D Ocean Circulation**: The reconfiguration of 3D ocean circulation in response to changes in cavity geometry leads to sustained and significant changes in basal melt rates. 3. **Net Ice-Shelf Mass Balance**: These feedbacks have a demonstrable impact on the net ice-shelf mass balance, including grounding-line discharge, over multi-decadal timescales. 4. **Future Projections**: The study highlights the importance of considering these geometric feedbacks in future projections of Antarctic mass loss, alongside changes in ice-shelf melt due to anthropogenic trends in ocean temperature and salinity. 5. **Model Setup and Experiments**: The coupled ice-sheet-ocean model Úa-MITgem is used to simulate the evolution of ice shelves and their response to changing ocean conditions. Experiments with fixed and time-varying ocean forcing conditions are conducted to isolate the effects of geometry and natural variability. 6. **Cavity Transfer Coefficients**: The study introduces cavity transfer coefficients to diagnose the feedbacks between changes in basal melt, ocean boundary conditions, and cavity geometry. These coefficients include the thermal transfer coefficient, momentum transfer coefficient, and outer-cavity transfer coefficient. 7. **Results and Analysis**: The results show that while changes in thermal driving at the ice front have a limited impact on melt rates, the geometrically constrained transport of water masses from the ice front to the interior cavity plays a crucial role in amplifying or damping these changes. 8. **Conclusion**: The study emphasizes the need to incorporate these geometric feedbacks into future climate change projections to better understand and predict the dynamics of West Antarctic ice shelves and their contribution to sea level rise.