Increasing the Glen–Nye Power‐Law Exponent Accelerates Ice‐Loss Projections for the Amundsen Sea Embayment, West Antarctica

Abstract Glacier flow is typically modeled using a power‐law rheology known as the Glen–Nye flow law, with the power assumed to be 3. However, recent research and past observations suggest that may better represent ice flow in some locations. We lack a quantitative understanding of how much affects ice‐loss projections, and its significance relative to other sources of uncertainty. Here, we test the effect of versus in a series of 300‐year forward simulations of the Amundsen Sea Embayment, West Antarctica. We find that in periods of rapid grounding line retreat, uncertainty in leads to a larger spread in ice‐loss projections than the spread due to uncertainty in climate forcing. The spatial sensitivity of is generally proportional to change in strain rates, so we expect regions undergoing more moderate dynamic change to be less sensitive to .