Suspended sediment export from land-terminating glaciers of the Greenland Ice Sheet (2016 – 2024), calculated from Sentinel-2 near infrared reflectance measurements, processed in Google Earth Engine

The Greenland Ice Sheet (GrIS) is a hotspot for sediment transport, where glaciers and their meltwaters deliver sediment and associated nutrients to proglacial outwash plains and the ocean. This outflux supports proglacial and marine ecosystems, where enhanced primary production can contribute to atmospheric CO₂ drawdown and negative carbon feedback loops. As field measurements of sediment export from the GrIS are limited both spatially and temporally, we use Google Earth Engine to extract suspended sediment concentrations from Sentinel-2 near infrared reflectance measurements of meltwater flows exiting land terminating glacier systems in Greenland (ground truthed by field data from Watson River, Kangerlussuaq), where sediment export analysis is facilitated by meltwater estimates from the Regional Atmospheric Climate Model (RACMO). Over the summer meltwater seasons of 2016 – 2024 we estimate a combined mean annual sediment flux of ~0.44 Gt yr^-1, where we note that export has increased at an average rate of ~0.001 Gtyr^-1 over the study period. Land terminating glaciers of the GrIS exported the greatest suspended sediment flux of 0.51 Gtyr^-1 in 2022 and the lowest export of 0.24 Gtyr^-1 in 2018. Regionally, southwest Greenland provides the greatest suspended sediment export per area, accounting for ~41% of total export over the study period. Our analysis provides the first estimate of proglacial sediment export from all land-terminating glacier systems in Greenland using Sentinel-2 imagery, allowing us to examine drivers of change and establish a baseline for assessing future changes in sediment delivery, as a result of climate warming. These changes will alter land systems in front of glaciers and impact sediment-derived nutrient delivery/ ecosystem response, with resultant implications for CO₂ drawdown.