Background: The Global Climate Observing System (GCOS) prepared its first assessment of the Adequacy of the Global Climate Observing System for the 4^th session of the Conference of the Parties (COP-4) of the UNFCCC in 1998. This report investigated the common assumption "that there are more than enough observations being collected to meet these [the Convention's] needs, especially given all the recent improvements in observational technologies. In practice, available observations often have major deficiencies with respect to climate needs." These deficiencies have the potential to lead to inaccurate conclusions concerning the mitigation of climate change.

Decision 5/CP.5 of the 5^th session of the COP invited all Parties to provide detailed reports on systematic observation in accordance with the UNFCCC reporting guidelines on global climate observing systems. Annex I Parties are to report in conjunction with their national communications (Decision 4/CP.5). Non-Annex I Parties are to report on a voluntary basis. Decision 5/CP.5 also invited the ‘Convention secretariat, in conjunction with the Global Climate Observing System secretariat, to develop a process for synthesising and analysing the information submitted’.

The UNFCCC secretariat will prepare a compilation and synthesis report (C&S) drawing together the basic information from national communications (NCs) received by November 2001. This will be prepared as soon as practicable after receipt of national communications as a UNFCCC document following normal Convention practice and should be available for consideration by SBSTA in mid-2002 to provide a preliminary analysis of support by Parties for systematic observation. The GCOS secretariat will assist in this process as requested in Decision 5/CP.5.

At its ninth session in September 2000, the GCOS Steering Committee (SC) requested that the GCOS secretariat extend this process to prepare a second assessment of the adequacy of the global observing systems for climate. The GCOS SC indicated that this should involve international experts in analysing the adequacy of the current global observing systems for climate in light of the national reports and any additional relevant data and information that are available from national, regional and international agencies including the research community. The GCOS SC believes that this analysis would be of significant benefit to the COP and that the proposal is consistent with Decision 14/CP.4.

Adequacy Assessment: The GCOS secretariat proposes that it co-ordinate and guide the preparation of a second assessment of the Adequacy of the Global Climate Observing Systems building on the synthesis and analysis of national reports and in the light of developments since the first adequacy assessment prepared for COP-4. The goal will be to determine what progress has been made since then in defining and implementing climate observing networks and systems and to assess how well current systems and planned improvements will meet the needs of the Convention.

The assessment will draw upon the expertise of scientific experts including members of the GCOS Science Panels, and will utilise data and information on operational and research observing systems from all available sources, such as national, regional and international organisations. The assessment will also address new developments and emerging opportunities such as the increasing capabilities shown by satellite systems to provide long-term, calibrated climate observations, and new techniques for integrating global in situ and satellite observations.

This proposal aims to ensure that the assessment will produce a soundly based scientific Report, with political credibility. It is envisaged that it will be a relatively succinct document, including supporting appendixes as required, totalling about fifty pages including a five-page executive summary.

Responsibility for conduct of the assessment and preparation of its Report will rest with a special task team of about ten to twenty scientists covering the GCOS spectrum. This task team will be guided by a smaller Committee drawn from the GCOS Steering Committee and with further representation nominated by the UNFCCC and such bodies as the IPCC. The assessment will be reviewed at an international scientific workshop of scientists nominated by Parties.

• July-October 2001 - Development of report outline and assessment process 
• November 2001 - Agreement on assessment framework by SBSTA/COP-7
• January-June 2002 - Work with UNFCCC Secretariat on synthesis of reports; Organise assessment team and compile additional information.
• July-December 2002 - Assessment team develops set of analyses of information from reports and other sources, and reaches preliminary conclusions.
• November 2002 - Progress report to COP-8
• April 2003 - International science workshop to review information from all sources and analyses from assessment team. Workshop develops a consensus on the conclusions.
• June 2003 - Preliminary findings to SBSTA
• June-October 2003 - Prepare final Adequacy Report
• November 2003 - Report conclusions to COP-9
• January-June 2004 - Complete final reviews and publish Adequacy Report