Linear-viscous flow of temperate ice

This is the authors' abstract. We don't add key points for this paper.

Accurately modeling the deformation of temperate glacier ice, which is at its pressure-melting temperature and contains liquid water at grain boundaries, is essential for predicting ice sheet discharge to the ocean and associated sea-level rise. Central to such modeling is Glen’s flow law, in which strain rate depends on stress raised to a power of n = 3 to 4. In sharp contrast to this nonlinearity, we found by conducting large-scale, shear-deformation experiments that temperate ice is linear-viscous ( n ≈ 1.0) over common ranges of liquid water content and stress expected near glacier beds and in ice-stream margins. This linearity is likely caused by diffusive pressure melting and refreezing at grain boundaries and could help to stabilize modeled responses of ice sheets to shrinkage-induced stress increases.