The Greenland Ice-Marginal Lake Inventory Series from 2016 to 2023

Abstract

Ice-marginal lakes form at the edge of the Greenland Ice Sheet and its surrounding peripheral glaciers and ice caps (PGIC), where outflowing glacial meltwater is trapped by a moraine, or by the ice itself, and create a reservoir that is in contact with the adjacent ice. While glacial meltwater is typically assumed to flow directly into the ocean, ice-marginal lakes temporarily store a portion of this runoff, influencing glacier dynamics and ablation, ecosystems, and downstream hydrology. Their presence, and change in abundance and size, remain under-represented in projections of sea level change and glacier mass loss. Here, we present an eight-year (2016-2023) inventory of 2918 automatically classified ice-marginal lakes (ĝ‰§0.05 km2) across Greenland, tracking changes in lake abundance, surface extent, and summer surface temperature over time. Fluctuations in lake abundance were most pronounced at the north (22 %) and northeast (14 %) PGIC margins and the southwest Ice Sheet margin (8 %). Over the study period, an increase in surface lake area was evident at 283 lakes, a decreasing trend was evident at 240 lakes, and 1373 remained stable (±0.05 km2). The northeast region contained the largest lakes, with a median size of 0.40 km2 at the ice sheet margin and 0.24 km2 at PGIC margins. Average summer surface temperatures fluctuated between 3.8 °C (2018) and 5.3 °C (2023), with spatial and temporal trends identified with possible links to lake setting and size. Validation against manually identified lakes showed 64 % agreement, yielding an error estimate of-809 lakes (36 %), while lake area uncertainty was ±5 %. Surface temperature estimates showed strong agreement with in situ measurements (r2Combining double low line0.87, RMSE Combining double low line1.68 °C, error ±1.2 °C). This dataset provides a crucial foundation for quantifying meltwater storage at ice margins and refining sea level contribution projections while supporting research on glacier-lake interactions, Arctic ecology, and environmental management. The inventory series is openly accessible on the GEUS Dataverse (10.22008/FK2/MBKW9N, ) with full metadata and documentation, and a reproducible processing workflow.