Work

Identifying Energy Balance Drivers of Greenland Ice Sheet Surface Melt Using Causal Discovery

Year: 2026

Type: article

Abstract: Greenland Ice Sheet (GrIS) mass loss has accelerated in recent decades, primarily due to enhanced surface melt. Identifying the causal dependencies of surface melt remains challenging with conventional correlations. Using the causal discovery algorithm applied to CESM2 large‐ensemble simulations and evaluated against two high‐resolution regional climate models, we identify significant contemporaneous positive links from melt to net shortwave radiation (reflecting melt–albedo feedback) and from sensible and latent heat fluxes to melt. These results highlight shortwave radiation and turbulent heating as dominant drivers of GrIS summer melt anomalies over the ablation zone at monthly timescales. Compared with correlations, isolates fewer but more physically interpretable dependencies. By the end of the century (SSP3‐7.0), these links persist but the turbulent heat‐related ones become undirected, indicating reduced statistical identifiability and possible stronger instantaneous surface–atmosphere coupling in a warmer climate.

Source: Geophysical Research Letters

DOI: 10.1029/2025gl119928