Glacier monitoring within the Global Climate Observing System

The fluctuation of mountain glaciers is recognized as a high-confidence indicator of air-temperature trends and as a valuable element of a strategy for early detection of possible Man-induced climate changes. The Terrestrial Observation Panel for Climate therefore recommended that glacier mass and area be monitored as part of the Global Climate Observing System (GCOS) established in 1992 by the World Meteorological Organization, the Intergovernmental Oceanographic Commission, the United Nations Environment Programme and the International Council of Scientific Unions. A tiered Global Hierarchical Observing Strategy was developed to be used for all GCOS terrestrial variables. According to this system of tiers, the regional to global representativeness in space and time of the records relating to glacier mass and area should be assessed by more numerous observations of glacier length changes as well as by compilation of regional glacier inventories repeated at time intervals of a few decades, the typical dynamic response time of smaller mountain glaciers. During the 1970s, Fritz Muller directed the Permanent Service on the Fluctuations of Glaciers and the Temporary Technical Secretariat for the World Glacier Inventory. These two bodies were combined in 1986 to form the World Glacier Monitoring Service, which is now responsible for internationally coordinated glacier monitoring, working in close collaboration with the World Data Center for Glaciology, Boulder.