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

The Little Ice Age (LIA) represents the latest multi-centennial cold period in the Holocene. In France, the maximum glacier extent was reached around 1820–1850. This study presents the first comprehensive, spatially explicit inventory of glaciers across metropolitan France - spanning both the 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 625.8 km², including 614.8 km² in the French Alps and 11.0 km² in the Pyrenees. Comparison with most recent glacier inventories (2022/2023) shows a total area loss of 66.2%, with a reduction of 65.7% in the Alps and 93.5% in the Pyrenees. The newly deglaciated areas are now undergoing rapid postglacial ecosystem development. The resulting geospatial database provides a robust baseline for quantifying glacier change, assessing ecological and hydrological impacts, and supporting hazard management and conservation strategies.