GCOS does not itself directly make observations nor generate data products. It stimulates, encourages, coordinates and otherwise facilitates the taking of the needed observations by national or international organizations in support of their own requirements as well as of common goals. It provides an operational framework for integrating, and enhancing as needed, observational systems of participating countries and organizations into a comprehensive system focussed on the requirements for climate issues. GCOS builds upon, and works in partnership with, other existing and developing observing systems such as the Global Ocean Observing System, the Global Terrestrial Observing System, and the Global Observing System and Global Atmospheric Watch of the World Meteorological Organization.

GCOS is directed by a Steering Committee which provides guidance, coordination and oversight to the programme. Three science panels, reporting to the Steering Committee, have been established to define the observations needed in each of the main global domains (atmosphere, oceans, and land), to prepare specific programme elements and to make recommendations for implementation. The GCOS Secretariat, located at the WMO headquarters in Geneva, Switzerland, supports the activities of the Steering Committee, the panels and the GCOS programme as a whole.

GCOS Ojectives

GCOS is intended to meet the needs for:

Climate system monitoring, climate change detection and monitoring the impacts of and the response to climate change, especially in terrestrial ecosystems and mean sea-level;

Climate data for application to national economic development;

Research toward improved understanding, modelling and prediction of the climate system.

GCOS Priorities

GCOS priorities are:

Seasonal-to-interannual climate prediction;

The earliest possible detection of climate trends and climate change due to human activities;

Reduction of the major uncertainties in long-term climate prediction;

Improved data for impact analysis.

GCOS will build, to the extent possible, on existing operational and research observing, data management and information distribution systems, and further enhancements of these systems. The GCOS will be based upon, inter alia :

Existing and enhanced World Weather Watch (WWW) systems;

The Global Atmosphere Watch (GAW) and related atmospheric constituent observing systems;

The Global Ocean Observing System (GOOS) for physical, chemical and biological measurements;

The Global Terrestrial Observing System (GTOS) for land surface ecosystem, hydrosphere, and cryosphere measurements;

The maintenance and enhancement of programmes monitoring other key components of the climate system, such as terrestrial ecosystems (including the International Geosphere-Biosphere Programme (IGBP)), as well as clouds and the hydrological cycle, the earth's radiation budget, ice sheets and precipitation over the oceans (including the World Climate Research Programme (WCRP));

Programmes to monitor the key physical, chemical and biological aspects of the impacts of climate change (including the World Climate Impact Assessment and Response Strategies Programme);

Data communication and other infrastructures necessary to support operational climate forecasting (including the World Climate Data and Monitoring Programme (WCDMP) and the Climate Information and Prediction Services (CLIPS)).