| 11 Nov 2025
21st century change in precipitation on the Greenland Ice Sheet using high resolution regional climate models
Abstract. An ensemble of regional climate model simulations downscaling global climate models within Coupled Model Intercomparison Project Phase 6 (CMIP6) is used to estimate future precipitation changes for the Greenland ice sheet under a range of climate change pathways. The regional climate models are HIRHAM5, MAR3.12 and RACMO2.3p2 contributing a total of eleven simulations for the SSP5-8.5 scenario, five simulations for the SSP2-4.5 scenario and four simulations for the SSP1-2.6 scenario. The Greenland ice sheet is divided into six drainage basins to evaluate the change in total (snow plus rain) precipitation in regions with different precipitation characteristics. Compared with the reference period 1971–2000, the ensemble median change in precipitation for the full Greenland ice sheet for the SSP5-8.5 scenario is estimated to be about +60 Gt (+8 %) per year during the 2031–2060 period and +170 Gt (+24 %) per year during the 2071–2100 period. We see similar ensemble median change for the 2031–2060 period for the SSP1-2.6 and SSP2-4.5 scenarios while the 2071–2100 change is +40 and +80 Gt (+6 and +11 %) per year for SSP1-2.6 and SSP2-4.5, respectively. In contrast to this, recent studies show that runoff is projected to increase by a much larger amount (around 2,000 Gt per year for the end of this century). Using linear regression on the annual mean change in near-surface (2 m) air temperature and precipitation over the ice sheet, we estimate an increase of about 35 Gt per year in precipitation (equal to about 5 %) for every degree of warming during the 21st century. We also study the change in phase of the total precipitation, showing a relative increase in rainfall, particularly along the outer edge and the southern part of the ice sheet. The regional climate model output is compared with an ensemble of global climate models within CMIP6 showing similar patterns in precipitation change but with overall larger changes in the CMIP6 ensemble median compared with the regional climate model ensemble median.
Competing interests: At least one of the (co-)authors is a member of the editorial board of The Cryosphere.
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