85 years of snowfall-driven ice sheet change in East Antarctica

Abstract Large-scale observational time series of pre-satellite era glacier changes in Antarctica are rare. In order to determine if recent trends are independent of natural variability, long-term observations are vital. Here we rediscover and explore the earliest, large-scale, aerial image archive of Antarctica to provide a unique record of 21 outlet glaciers along the coastline of East Antarctica since the 1930s. We combine the imagery with more recent Australian aerial photographs (1956-1973) to provide historical glacier reconstructions through multiple epochs. The historical reconstructions are compared to modern satellite observations to study glacier elevation changes over 85 years, allowing us to distinguish long-term trends from shorter-term variability. The aerial images reveal two distinct regional patterns: In Lützow-Holm Bay, Dronning Maud Land, the ice elevations remained stable, however with a concurrent frontal retreat of all glaciers in the 1980s and indications of a weakening of the localized land-fast sea-ice conditions. Along the coastline of Kemp, Mac Robertson, and Ingrid Christensen Coast, we observe a general thickening of the glaciers. We find that the regional differences in observed ice thickness are consistent with the overall trends in snowfall since 1940. Additionally, our results demonstrate that the stability and growth observed in terrestrial basins over the past few decades are part of a longer-term trend spanning at least a century.