What glaciers are telling us about Earth's changing climate

Abstract. A glacier monitoring system has been developed to systematically observe and document changes in the size and extent of a representative selection of the world's 160 000 mountain glaciers (entitled the PTAAGMB Project). Its purpose is to assess the impact of climate change on human societies by applying an established relationship between glacier ablation and global temperatures. Two sub-systems were developed to accomplish this goal: (1) a mass balance model that produces daily and annual glacier balances using routine meteorological observations, (2) a program that uses Google Maps to display satellite images of glaciers and the graphical results produced by the glacier balance model. The recently developed PTAA glacier balance model is described and applied to eight glaciers to produce detailed mass balance reports. Comparing annual balances produced by the model to traditional manual measurements for 50–60 years yields R² values of 0.50–0.60. The model also reveals an unusual but statistically significant relationship between the average ablation of Wrangell Range glaciers and global temperatures that have been derived from temperature data at 7000 stations in the Northern Hemisphere. This glacier ablation/global temperature relationship provides the means to use worldwide ablation results to anticipate problems caused by climate change.