Much has changed in our approach to observing, understanding, predicting and protecting the natural systems of the planet since the vision for a Global Climate Observing System (GCOS) was first elaborated at the Second World Climate Conference in 1990. But the fundamental need, for a wide variety of purposes and users, for a comprehensive and coordinated global system to observe the structure and behaviour of climate on all time and space scales and across the physical domains of atmosphere, ocean and land has not changed.

In fact, the need for a sustained, operational GCOS based on the in situ and space-based observing systems of the World Meteorological Organization (WMO) World Weather Watch and the many other purpose- and domain-specific observing systems of WMO, the Intergovernmental Oceanographic Commission (IOC) of UNESCO, the United Nations Environment Programme (UNEP), the International Council for Science (ICSU) and various other international organisations has increased dramatically and extended far into the social science domains needed to study the impacts of climate on human systems and the impacts of humanity on climate and to develop global and national strategies for living with climate change.

The 1995 GCOS Plan set down the broad strategy for the realization of the original vision for GCOS based on the strengthening and enhancement of the various components of its Initial Operational System. With the support of the Conference of the Parties to the UN Framework Convention on Climate Change (UNFCCC) and the UN Development Programme, the joint WMO-IOC-UNEP-ICSU Steering Committee and Secretariat organised a series of Regional Workshops for the development of GCOS Regional Action Plans to strengthen and expand the climate observing capabilities of the component observing systems in the developing countries. Then, in 2004, the GCOS Steering Committee responded to the specific needs of the Convention by the production of an ‘Implementation Plan for the Global Observing System for Climate in support of the UNFCCC' based on the identification of, and assessment of requirements for, a set of ‘Essential Climate Variables' identified through an adequacy assessment and wide consultation with both the provider and user communities.

The progressive development and implementation of GCOS as an integrated system based on the climate-relevant components of existing environmental observing systems provided the essential architectural prototype for proposals, through the late 1990s and early years of the 21st century, for a still broader global earth observation system to meet the full range of user needs for weather, climate, water and other earth system data and information. Following the development, by an ad hoc group of countries (the Group on Earth Observations (GEO)), of a ten-year Implementation Plan for a Global Earth Observation System of Systems (GEOSS), the Steering Committee of GCOS, its Panels and its Secretariat have focussed their efforts on ensuring the coordinated development of GCOS as the climate observing system of the GEOSS system of systems.

This presentation will outline overall strategy for the future development of GCOS within the framework of GEOSS and the guidance provided by the recent sessions of the governing bodies of its four co-sponsoring international organisations.