The Global Earth Observation System of Systems (GEOSS) is being built by the Group on Earth Observations (GEO) on the basis of a 10-Year Implementation Plan running from 2005 to 2015. GEOSS seeks to connect the producers of environmental data and decision-support tools with the end users of these products, with the aim of enhancing the relevance of Earth observations to global issues. GEOSS aims to produce a global public infrastructure that generates comprehensive, near-real-time environmental data, information and analyses for a wide range of users. The Secretariat Director of Geoss is Barbara Ryan. The Global Earth Observation System of Systems (GEOSS) is being built by the Group on Earth Observations (GEO) on the basis of a 10-Year Implementation Plan running from 2005 to 2015. GEOSS seeks to connect the producers of environmental data and decision-support tools with the end users of these products, with the aim of enhancing the relevance of Earth observations to global issues. GEOSS aims to produce a global public infrastructure that generates comprehensive, near-real-time environmental data, information and analyses for a wide range of users. The Secretariat Director of Geoss is Barbara Ryan. Earth observation systems consist of instruments and models designed to measure, monitor and predict the physical, chemical and biological aspects of the Earth system. Buoys floating in the oceans monitor temperature and salinity; meteorological stations and balloons record air quality and rainwater trends; sonar and radar systems estimate fish and bird populations; seismic and Global Positioning System (GPS) stations record movements in the Earth’s crust and interior; some 60-plus high-tech environmental satellites scan the planet from space; powerful computerized models generate simulations and forecasts; and early warning systems issue alerts to vulnerable populations.