A flowline model for Nigardsbreen, Norway: projection of future glacier length based on dynamic calibration with the historic record

Historic glacier-length variations are used to constrain a computer model for Nigardsbreen, Norway. A mass-balance history is derived that, when imposed on the flow model, gives an almost perfect match between observed and simulated glacier length since AD 1748. Being calibrated with past changes, the model predicts an 800 m advance of the glacier snout if mass-balance conditions remain as they were for the period 1962-93. Several greenhouse-warming scenarios are imposed to project the glacier's behaviour into the next century. For a uniform heating rate of 0.02 K a(-1), Nigardsbreen would advance slightly until AD 2020, but then a very rapid retreat would start: in AD 2100 glacier volume would be only 10 % of the 1950 volume.