Global sea level rise due to increased melting of mountain glaciers and ice caps assessed with a gridded glacier-climate model

The sensitivity of global sea level to increased melting of mountain glaciers and ice caps under warmer temperatures is estimated. This involves estimating the temperature sensitivity of glacier mass balance for grid squares containing glaciers, multiplying by the appropriate glacier area, and summing over all grid squares with glacier cover, excluding Greenland and Antarctica. The temperature sensitivity of mass balance for each grid square is calculated from precipitation in a gridded climatology using a relationship based on degree day modelling for 61 individual glaciers. Smaller mass balance sensitivities occur for dry cold (continental) glaciers and larger sensitivities for warm-wet (maritime) glaciers. The globally averaged mass balance sensitivity is -0.41 m a-1 deg-1 in good agreement with the value found earlier by J. Oerlemans. The global sea level sensitivity is 0.62 to 0.81 mm a 1 deg 1, depending on which value is used for global glacier area. Regional contributions to sea level sensitivity agree quite well with earlier values found by M. F. Meier in 1984 and J. Oerlemans in 1993. Glaciers in mainland North America contribute most to sea level sensitivity (33 % of the global total) followed by glaciers in Asia (24 %), Arctic North America (12 %), South America (9 %), Svalbard (8 %), Russian Arctic islands (6%) and Iceland (5 %).