Abstract

Global sea-level rise is, in part, caused by more rapid ice discharge from Antarctica to the ocean, following the removal of the restraining forces of floating ice shelves after their break-up. A trigger of ice-shelf disintegration is thought to be surface-stress variations associated with surface meltwater ponding and draining, causing weakness and fracture. For example, the explosive disintegration of the Larsen B ice shelf in 2002 is thought to have been caused by the widespread drainage of >2500 surface lakes observed in the days prior to break up event. This talk will first describe the results of a modelling study that demonstrated that the collapse of the Larsen B ice shelf may have been triggered by a chain-reaction style lake drainage process. Second, field data from the austral summer of 2016/2017 will be presented to show that the filling and draining of surface lakes on the McMurdo ice shelf in Antarctica does indeed cause significant (and simultaneous) ice-shelf flexure. Until now, no study has provided field-based data to either demonstrate this process, or to improve and constrain the physical representation of ice shelves in current ice-sheet models.