Glacier-melting debate highlights importance of satellites

The intense public debate on how rapidly the Himalayan glaciers are retreating highlights the necessity for the constant monitoring of glaciers worldwide by satellites. Considering the valuable role satellites can play in determining the state of Earth’s glaciers, the Global Climate Observing System (GCOS) has called for the systematic monitoring of glaciers by satellites in support of the UN Framework Convention on Climate Change.  In 2007, ESA started the GlobGlacier project as a major effort to develop and apply existing methodologies to monitor glaciers and contribute to a global glacier inventory using satellite observations. GlobGlacier, part of ESA’s ‘Data User Element’, is adding about 20,000 of the estimated 160,000 glaciers worldwide to this inventory to allow their histories to be adequately tracked. The inventory combines information on glacier outlines based on archived satellite data from the Landsat Thematic Mapper (TM) and the Enhanced Thematic Mapper Plus (ETM+) instruments with topographic information from the Shuttle Radar Topography Mission and the Global Digital Elevation Model (GDEM) from ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer). When a time series of suitable images are available for a certain region, changes in glacier length and extent can be calculated.  ESA’s new Climate Change Initiative, which will produce robust long-term records of essential climate variables, will build on the results of the GlobGlacier project by further improving the algorithms for glacier monitoring and continually updating the related glacier inventory information.

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