Toward a universal glacier slip law

Glaciers and ice sheets shape Earth's surface and are important components of the climate system. Among the notable effects of glacier flow are erosion and sedimentation of Earth's surface and variations in sea level as glaciers lose or gain mass. These effects depend on the slip of glaciers along their beds, which is accompanied by drag at ice-bed interfaces. Parameterizations of drag with slip rate are called sliding or slip laws. Recent acceleration in glacier flow and rates of mass loss in Greenland and Antarctica highlight the need to better understand and parameterize glacier sliding (1–4). On page 76 of this issue, Zoet and Iverson (5) present a slip law for deformable sediment that is similar to laws derived for rigid beds, thereby supporting a universal slip law that could improve projections of ice sheet contributions to sea level