Glacier Equilibrium‐Line Altitude Change Across Alaska and Adjacent Canada Indicates a Cold, Dry Little Ice Age and Weaker Aleutian Low

Abstract As Arctic warming accelerates, understanding hydroclimate shifts is key to projecting glacier melt and sea‐level rise. We assess the climatic signature of the Little Ice Age (LIA; ∼1250 to 1900) by quantifying changes in equilibrium‐line altitude (ΔELA) for 215 Alaskan glaciers from the LIA maximum to present (2016–2024), using remote sensing and geographic information system methods. ELAs have risen by 170 ± 8 m, equivalent to 1.6 ± 0.3°C summer warming (assuming constant precipitation) or 248 ± 89 mm w.e. annual precipitation increase (assuming 2.3°C warming). The latter is ∼4X the precipitation change observed since 1950. Glacier morphology and topographic setting explain 32% of ΔELA variance, likely reflecting differing sensitivities to climatic shifts and elevation‐dependent warming. Spatially interpolated ΔELA residuals are most strongly correlated to winter precipitation ( r = −0.67). Results suggest the LIA was characterized by (a) colder, drier conditions and (b) a weak, westward‐displaced Aleutian Low that has since strengthened and shifted eastward.