Accelerating future mass loss of Svalbard glaciers from a multi-model ensemble

Abstract Projected climate warming and wettening will have a major impact on the state of glaciers seasonal snow in High Arctic regions. Following up historical simulation (1957–2018) for Svalbard, we make future projections glacier climatic mass balance (CMB), conditions land, runoff, under Representative Concentration Pathways (RCP) 4.5 8.5 emission scenarios 2019–60. We find that average CMB Svalbard glaciers, which was weakly positive during 1957–2018, becomes negative at an accelerating rate 2019–60 both RCP scenarios. Modelled loss is most pronounced southern where equilibrium line altitude predicted to rise well above hypsometry peak, leading first occurrences zero accumulation-area ratio already by 2030s. In parallel with firn retreat, total pore volume drops as much 70–80% 2060, compared 2018. Total refreezing remains largely unchanged, despite marked change pattern towards increased winter. Finally, shortening season, while combined runoff from land more than doubles 1957–2018 2019–60,