A glacier inventory for the last Little Ice Age maximum in mainland France

The Little Ice Age (LIA) represents the latest multi-centennial cold period in the Holocene. In mainland France, the maximum glacier extent was reached around 1820–1850. This study presents the first comprehensive, spatially explicit inventory of glaciers across the French Alps and Pyrenees at the last LIA maximum. The glacier outlines were reconstructed using a combination of glacio-geomorphological, historical, and bibliographic approaches. Our results indicate that, at the last LIA maximum, glaciers covered 632.00 km², 620.93 km² in the French Alps and 11.07 km² in the French Pyrenees. Comparison with most recent glacier inventories (2022/2023) shows a total area loss of 66.52%, with a reduction of 66.03% in the Alps and 93.77% in the Pyrenees. The deglaciated areas are now undergoing rapid postglacial ecosystem development. The resulting geospatial database provides a robust baseline for quantifying glacier changes, assessing ecological and hydrological impacts, and supporting hazard management and conservation strategies.