Since the beginning of internationally-coordinated, systematic observations on glacier variations in 1894, a valuable and increasingly important data basis on glacier changes has been built up. In 1986, the World Glacier Monitoring Service (WGMS) started to maintain and continue the collection of information on ongoing glacier changes, when the two former International Commission on Snow and Ice (ICSI) services Permanent Service on Fluctuations of Glaciers (PSFG) and Temporal Technical Secretary/World Glacier Inventory (TTS/WGI) were combined.

As a contribution to the Global Environment Monitoring System Global Terrestrial Observing System (GEMS/GTOS) of the United Nations Environment Programme (UNEP) and to the International Hydrological Programme (IHP) of the United Nations Educational, Scientific and Cultural Organisation (UNESCO), the WGMS of the ICSI International Association of the Hydrological Sciences (IAHS) and the Federation of Astronomical and Geophysical Data Analysis Services (FAGS)/International Commission on Snow and Ice (ICSU) today collects and publishes worldwide standardized glacier data. At present, the WGMS gets important financial and logistic support from the University of Zürich and the Swiss Federal Institute of Technology, Zürich. The tasks of the WGMS are to continuously upgrade, collect and periodically publish glacier inventory and fluctuation data, as well as to include satellite observations of remote glaciers and to assess ongoing changes. The WGMS database stores two types of data: The World Glacier Inventory (WGI) contains glacier data describing the spatial variability, and the Fluctuations of Glaciers (FoG) contains data documenting changes over time. These data are stored at the ETH on the database system 'Oracle', which allows fast and selective data access. Glacier inventory data are an excellent tool in detecting regional climate-change effects. By applying a parameterization scheme on basic glacier inventory data, it is possible to assess and simulate regional aspects of past and future climate changes. Such a scheme was successfully applied to the European Alps. Long-term mass balance measurements for selected glaciers are a valuable regional climate signal and help with understanding the processes of energy- and mass exchange at the glacier-atmosphere interface. As only a few glaciers can be observed in detail, it is necessary to extend mass-balance information in space. Over time spans which match or exceed the characteristic dynamic response time it is possible to assess mass-balance information using glacier-termini changes. With this method not only secular mass-balance evolutions can be analysed but also information during the whole Holocene glacier-climate history be gained, which is certainly a key issue with respect to the present global-change discussion.

In a time with limited funding possibilities and observation networks being under increasing pressure, cost-saving technologies for long-term glacier observations must be developed and applied. Aerial photogrammetric and satellite imaging and laser-altimeter techniques must become more widely applied to observe glacier length, area changes, and changes in surface elevation at a global scale. It is of fundamental importance to maintain the current mass-balance programmes for assessing the representativity of results from remote sensing and modelling in view of potential acceleration of atmospheric warming.

A recently completed report from a WGMS Review Panel to the ICSI bureau recognizes the importance of a WGMS to the scientific community and notes a 'considerable interest'. The WGMS is expanding its efforts to serve the user community in getting high quality and easy accessible data. This will happen through data exchange with the World Data Center A for Glaciology (WDC-A) and the Global Resources Information Database (GRID) of GEMS as well as the WWW homepage, where the user will have the opportunity to directly access the database of the WGMS (http://www.geo.unizh.ch/wgms). An ICSI working group was established to help improve the funding for WGMS.

Bibliography

Fluctuations of Glaciers:

IAHS(ICSI)/UNEP/UNESCO, 1988, Fluctuations of Glaciers 1980-1985; Haeberli, W., and Müller, P., eds.: Paris.

IAHS(ICSI)/UNEP/UNESCO, 1993a, Fluctuations of Glaciers (1985-1990, Haeberli, W., and Hoelzle, M., eds., Paris.

IAHS(ICSI)/UNESCO, 1977b, Fluctuations of glaciers 1970-1975: Müller, R., ed., Paris.

IAHS(ICSI)/UNESCO, 1985, Fluctuations of glaciers 1975-1980: Haeberli, W., ed., Paris.

UNESCO, 1969, Variations of existing glaciers: UNESCO/IAHS Technical Papers in Hydrology 3.

Glacier Inventory:

IAHS, 1980, World Glacier Inventory - Proceedings of the workshop at Riederalp, Switzerland, 17-22 September 1978: IAHS Publication 126.

IAHS(ICSI)/UNEP/UNESCO, 1977a, Instructions for the compilation and assemblage of data for a world glacier inventory; Supplement: Identification/glacier number, Müller, F., ed., Temporal Technical Secretariat for the World Glacier Inventory (TTS/WGI), ETH Zürich.

IAHS(ICSI)/UNEP/UNESCO, 1983, Guidelines for preliminary glacier inventories, Scherler, K., ed., Temporal Technical Secretariat for the World Glacier Inventory (TTS/WGI), ETH Zürich.

IAHS(ICSI)/UNEP/UNESCO, 1989, World glacier inventory - status 1988, Haeberli, W., Bösch, H., Scherler, K., Østrem, G., and Wallén, C.C., eds., Nairobi.

Haeberli, W., and Hoelzle, M., 1995, Application of inventory data for estimating characteristics of and regional climate change effects on mountain glaciers -- a pilot study with the European Alps. Annals of Glaciology, v. 21, p. 206-212.

UNESCO, 1970, Perennnial ice and snow masses. A guide for compilation and assemblage of data for a World Glacier Inventory: UNESCO/IAHS Technical Papers in Hydrology 1.

UNESCO, 1970/73, Combined heat, ice and water balances at selected glacier basins. Part I: A guide for compilation and assemblage of data for glacier mass balance measurements. Part II: Specifications, standards and data exchange: UNESCO/IAHS Technical Papers in Hydrology 5.

Glacier Mass Balance Bulletin:

IAHS(ICSI)/UNEP/UNESCO, 1991, Glacier mass balance bulletin no. 1, Haberli, W., and Herren, E., eds.: World Glacier Monitoring Service, ETH Zürich.

IAHS(ICSI)/UNEP/UNESCO, 1993, Glacier mass balance bulletin no. 2, Haeberli, W., Herren, E., and Hoelzle, M., eds., World Glacier Monitoring Service, ETH Zürich.

IAHS(ICSI)/UNEP/UNESCO, 1994, Glacier mass balance bulletin no. 3, Haeberli, W. Hoelzle, M, and Bösch, H., eds., World Glacier Monitoring Service, ETH Zürich.

IAHS(ICSI)/UNEP/UNESCO, 1996, Glacier mass balance bulletin no. 4, Haeberli, W. Hoelzle, M, and Bösch, H., eds., World Glacier Monitoring Service, ETH Zürich.

Global Glacier Monitoring:

Haeberli, W., in press, Historical evolution and operational aspects of worldwide glacier

monitoring, in Haeberli, W., Hoelzle, M. and Suter, S., eds., Into the Second Century of World Glacier Monitoring - Prospects and Strategies: Paris, UNESCO publishing.

Hoelzle, M. And Trindler, M., in press, Data management and application, in Haeberli,

W., Hoelzle, M. and Suter, S., eds., Into the Second Century of World Glacier Monitoring - Prospects and Strategies: Paris, UNESCO publishing.

General/Overviews:

Haeberli, W.,1995, Glacier fluctuations and climate change detection--operational elements of a worldwide monitoring strategy: WMO Bulletin 44, v. 1, p. 23-31.

Haeberli, W., 1996, glacier fluctuations and climate change detection: Geografia Fisica e Dinamica Quaternaria, v. 18, p. 191-199.

Haeberli, W., Müller, P., Alean, P., and Bösch, H., 1989, Glacier changes following the Little Ice Age--a survey of the international data basis and its perspectives, in Oerlemans, J., ed., Glacier Fluctuations and Climatic Change: Kluwer, p. 77-101.

UNEP, 1991, Environmental data report: Third edition 1991-92, Oxford, Blackwell.

UNEP, 1992, Glaciers and the environment: UNEP/GEMS Environment Library 9.

UNEP, 1994, Environmental data report: Fourth Edition 1993-94, Oxford, Blackwell.