Calving and Surging Glaciers: Observations, Modelling, Predictions

Calving and surging are both complex dynamic phenomena that exert strong controls of the flux of ice into the oceans. Calving - the breakaway of icebergs from glaciers into the sea - accounts for a large proportion of ice flux from Arctic glaciers and the Greenland and Antarctic ice sheets, and is a major source of uncertainty in projections of future sea-level change. Surges are dramatic, sometimes periodic, speed-ups of glacier flow resulting from switches in conditions at the glacier bed. Svalbard is a n excellent natural laboratory for studying both of these poorly understood phenomena. The archipelago contains one of the richest clusters of surging glaciers on Earth, and recent investigations have revealed a wide variety of dynamic glacier behaviors, including rapid advances and retreats out of synch with climatic and oceanic forcing. Svalbard's glaciers are also more accessible than those in comparable regions, offering exciting opportunities for research that may be difficult or impossible elsewhere . Calving and surging both involve the interactions of several glaciological processes, each of which presents considerable research problems in their own right. These include fracture me-chanics, fast glacier flow by sliding and soft-sediment deformatio n, subglacial hydrology, and the generation and dissipation of heat (thermodynamics). Understanding calving and surging, therefore, requires a multi-disciplinary approach and the convergence of different research groups with a wide variety of experience, expertise and perspectives.