Mountain glaciers are sensitive indicators of climate change and an important hydrological resource. Estimating the decline of mountain glaciers is important for better understanding spatio-temporal patterns of climate change and for better predicting future availability of glacial melt water for the one-sixth of the human population that depends on it for subsistence. The need for worldwide monitoring of mountain glaciers is evidenced by the existence of large international efforts devoted to this purpose, such as the Global Land Ice Measurements from Space (GLIMS) and the World Glacier Monitoring Service (WGMS) databases. Ground measurements are invaluable where they exist, but less than 5% of all mountain glaciers have been continuously monitored.

The key to effective evaluation of mountain glaciers is to use time sequences of imagery data from geosurveillance satellites such as Landsat, which have been photographing the Earth for the last 40 years. We created a processing and analysis pipeline to quantify and map the temporal trends in the area and terminus position of mountain valley glaciers worldwide, using satellite imagery data and accessory information from the GLIMS and WGMS databases. This entailed the development of statistical methodology for analysis of sequences of images over time, as well as development of a web application for data access and visualization of results.

A more spatially complete estimate of changes in glacier position will permit for global documentation of changes in mountain valley glacier lengths as well as exploration of regional patterns of variability.

bolivia The Laguna glacier in Bolivia.

water supply One-sixth of the human population rely on glacier runoff for subsistence.