Bridging the gap between the modern and historical: Extending the mass balance reconstruction of the Greenland Ice Sheet from 1421 to 2024 AD

Bridging the knowledge gap between the recent decades and the preceding centuries of Greenland Ice Sheet (GrIS) history is essential for improving projections of its contribution to future sea-level rise. Evidence from relative sea-level reconstructions from salt marshes in southern Greenland suggests that GrIS mass loss began around 1850, well before significant anthropogenic warming—a pattern not yet captured in existing simulations of late Holocene GrIS evolution. Extending reconstructions of GrIS surface mass balance (SMB) as far back as possible, by leveraging newly available climate datasets from ~AD 1400 is critical to understanding its sensitivity to climate forcings during key periods such as the Little Ice Age. 

By addressing the underrepresentation of dynamic components and calculation of pre-20th century mass changes, this project aims to provide critical insights into GrIS-climate interactions and refine predictions of GrIS contributions to global sea-level rise. To achieve this aim, we will first  develop a 1x1-km resolution monthly SMB dataset using ModE-RA, a new palaeoclimate reanalysis product spanning 1421-2024.  This new SMB dataset will be used as input to ice sheet model simulations to assess the  spatial and temporal interplay between climate, SMB and ice dynamics.

Here we will present initial results of (1) GrIS temperature, precipitation and SMB fields for 1421 to 2024 AD and (2) historical simulations using the ice sheet model Úa to reconstruct ice thickness and margin changes outside of the observational period.