The future sea-level rise contribution of Greenland's glaciers and ice caps

We calculate the future sea-level rise contribution from the surface mass balance of all of Greenland's glaciers and ice caps (GICs, similar to 90 000 km(2)) using a simplified energy balance model which is driven by three future climate scenarios from the regional climate models HIRHAM5, RACMO2 and MAR. Glacier extent and surface elevation are modified during the mass balance model runs according to a glacier retreat parameterization. Mass balance and glacier surface change are both calculated on a 250 m resolution digital elevation model yielding a high level of detail and ensuring that important feedback mechanisms are considered. The mass loss of all GICs by 2098 is calculated to be 2016 +/- 129 Gt (HIRHAM5 forcing), 2584 +/- 109 Gt (RACMO2) and 3907 +/- 108 Gt (MAR). This corresponds to a total contribution to sea-level rise of 5.8 +/- 0.4, 7.4 +/- 0.3 and 11.2 +/- 0.3 mm, respectively. Sensitivity experiments suggest that mass loss could be higher by 20-30% if a strong lowering of the surface albedo were to take place in the future. It is shown that the sea-level rise contribution from the north-easterly regions of Greenland is reduced by increasing precipitation while mass loss in the southern half of Greenland is dominated by steadily decreasing summer mass balances. In addition we observe glaciers in the north-eastern part of Greenland changing their characteristics towards greater activity and mass turnover.