Predicted response of Storglaciaren, Sweden, to climatic warming

A time-dependent model of glacier flow was used to predict the response of Storglaciaren, a small valley glacier in northern Sweden, to different warming scenarios by imposing two possible climatic forcings: one in which temperature alone increases (T model), and one in which both temperature and precipitation increase (TP model). A range of possible changes in temperature and/or precipitation was related to changes in glacier mass balance through a multiple linear correlation of mean specific net balance with mean summer temperature and mean specific winter balance. The T model was run with mass-balance perturbations in the form of linear increases from the recent (1980-89) mean summer temperature of 1, 2 and 4 degrees C over the next 100 years. Perturbations for the TP model also used linear increases in precipitation of 10, 20 and 50% over current mean winter values in addition to increases in temperature. Results of the modeling suggest that initial changes in the glacier's profile due to increases in temperature, or in both temperature and precipitation, are of comparable magnitude to those that might be expected as the glacier completes its response under the existing climate. Changes in the glacier's surface profile and terminus position that can, with some certainty, be attributed to climatic warming may only become apparent several decades after warming has begun.