Statement of Need
All societies and ecological systems are affected by climate change (including long-term climate change, natural climate variability and extreme weather and climate events). Improved knowledge of climate change underpins many other societal benefit areas. As the state of the ‘climate system’ is described by statistical properties, usually with a 30 year base period, obtained from sufficiently long observations of the state of the atmospheric, oceanic, and terrestrial domains, there is a need, firstly, to have long and homogeneous time series of the required observations in each of these domains. Furthermore, it is necessary to identify the underlying dynamic processes to improve our knowledge of the changing climate. Risks associated with the observed trend of global warming and other changes, including extreme events, are often poorly known or not fully recognized when planning for socio-economic development. For adaptation to be effective, governments as well as the private sector need information about past and current climate conditions, and their variability and extremes. In addition, they need sound projections of future conditions, not only on a year-on-year basis, but also for many decades into the future.
Vision and How GEOSS will Help
The vision is to establish a climate observation system of systems that will allow us to improve our understanding of the Earth’s climate system and the ability to predict climate change, and to mitigate and adapt to climate change and variability. This will enable economic and societal development in a sustainable way, with minimum perturbations on the climate system.
Existing Situation and Gaps
The IPCC Third Assessment Report (IPCC, 2001) highlighted scientific uncertainties that need additional research as well as new observational data. The Essential Climate Variables (ECVs) required for climate monitoring are identified in the Global Climate Observing System (GCOS) Second Report on the Adequacy of the Global Observing Systems for Climate in Support of the UNFCCC, GCOS-82 (GCOS, 2003), hereinafter “GCOS Second Adequacy Report,” and in the IGOS-P Theme Reports. Research activities aimed at improving our capability to predict climate variability and change are coordinated by the World Climate Research Programme (WCRP) and include observation, modeling, data assimilation, re-analysis and process studies programmes. The WMO World Climate Data and Monitoring Programme (WCDMP) coordinates data and monitoring activities, including the development of climate indices. The observational networks, especially the terrestrial and ocean networks, are incomplete and are still to be fully implemented. The Global Terrestrial Networks (e.g. for glaciers, for hydrology, and for permafrost) should be fully implemented, gaps in the measurement networks that they have highlighted should be filled, and data should be provided to the designated international data centres. The ocean networks lack global and full depth coverage and commitment to sustained operation. There is a need to complete the deployment and subsequent maintenance of the global Argo float array and the global tropical moored buoy array, and to enhance these platforms with measurement capabilities for physical and chemical parameters presently only provided by research ships. The atmospheric networks are not operating with the required global coverage and quality, and both the GCOS Surface Network and the GCOS Upper Air Network stations still need to be fully implemented. Surface-based atmospheric composition monitoring is currently mainly served by a sparse surface network for the long-lived gases and an inhomogeneous ozone sonde network. Space-based observations are an essential part of the global observing systems for climate. Their contributions have not yet realized their full potential because the mission design parameters have not considered the long-term climate monitoring requirements.