Change of topographic control on the extent of cirque glaciers since the Little Ice Age

Abstract

This paper analyses the influence of topography on the extent of cirque glaciers for four different stages since the Little Ice Age (LIA). The study focuses on a Pyrenean massif affected by a marked glacial shrinkage. Modeled distributed probabilities of glacier development during each stage from terrain characteristics enabled us to: (1) quantify the percentage of variance of the glacier distribution explained by topography; (2) assess the influence of individual variables on ice extent at each stage; and (3) identify those areas most vulnerable to ice degradation during the subsequent stage. Results show that topography has a greater influence on ice extent during times of warmer climate. In addition, the relative role of the different topographic variables changed over time. The probabilities of ice existence predicted by the models for subsequent stages are in good agreement with the observed paths of glacier retreat. Thus, topography should be considered a key factor in further research into the impact of climate change on glacier evolution.