Greenland Ice Sheet under climate change: Perspective from a high-resolution modelling simulation from 1421-2024

The Greenland Ice Sheet (GrIS), a major driver of global sea-level rise, holds approximately 7 meters of sea-level equivalent. Despite its critical role, significant uncertainties remain about its mass balance and response to climate forcing over the past few centuries, particularly before the satellite era. This study aims to address these gaps by reconstructing a high-resolution (1x1 km) monthly surface mass balance (SMB) dataset spanning AD 1421–2024 and quantifying its contributions to historical and contemporary sea-level changes using the Positive Degree Day (PDD) modelling approach. 

The novel SMB dataset integrates long-term climate reanalysis inputs (ERA5 and ModE-RA). They are then validated and corrected against available ice-core records and weather station observations using a Bayesian approach to formally constrain the uncertainties. Preliminary analysis indicates signidficant SMB-driven mass loss due to climatic forcing during recent past, potentially offering new insights into the relative contributions of SMB and ice dynamics to GrIS total mass changes during latter half of the last millennium. 

These results represent a significant advancement in understanding the GrIS’s historical behaviour and links with climate change and can form a valuable baseline for improving the accuracy of future SMB and sea-level rise projections. By addressing critical knowledge gaps, this work enhances our ability to predict the long-term impacts of climate change on the GrIS and global sea levels.