Challenges to Developing a Global Satellite Climate Monitoring System
Satellites are critical to the ability to understand and address climate change, due to their unique ability to provide comprehensive global monitoring of the environment. More than 30 nations have been involved in satellite Earth observations, with more than 200 satellite instruments operating in 2014 alone. However, gaps remain in the ability to adequately monitor global climate change, due in part to a lack of international consensus on the definition of an adequate monitoring system. This paper examines ongoing international efforts to identify the requirements of a global satellite climate monitoring system, including high-level efforts by the Global Climate Observing System (GCOS), the World Meteorological Organization (WMO), and the Committee on Earth Observing Satellites (CEOS), as well as efforts to define more detailed technical requirements being undertaken by GCOS, WMO, and the European Space Agency (ESA). Comparing the distinct processes and interim results of these groups highlights the lack of international consensus on the definition of an adequate global climate monitoring system. Developing such a system is a complex, multifaceted challenge, which requires expert technical knowledge of climate science and satellite capabilities as well as attention to political concerns for sovereignty and long-term international cooperation. The paper examines the adequacy of the current satellite monitoring capabilities by developing a comprehensive dataset including all unclassified Earth observation satellites operating or planned between 1990 and 2020. This analysis shows that within each international effort, gaps in the type of data collected are present. Even when some data is collected on a particular variable, it is not necessarily done in a way that meets technical requirements for climate assessment and forecasting. A lack of free and open data sharing compounds this challenge, further decreasing the amount of data contributing to international climate monitoring efforts. The lack of consensus on the requirements of a global climate monitoring system makes it difficult for nations to use international coordination mechanisms to plan and prioritize future satellite systems. The paper concludes by providing a series of recommended steps to improve harmonization among international efforts. This includes coordinating the bottom-up method used within GCOS with the top-down method used at WMO to identify concrete recommendations that will allow nations to prioritize investments that improve climate monitoring and/or improve the efficiency of the existing system. It recommends consolidating international efforts to define technical requirements to avoid duplication and facilitate prioritization among user groups with regard to which variables should be collected and what technical requirements must be met. A more systematic and integrated approach to system definition will make it possible for nations to shift and/or increase investments in satellite technology to better address agreed-upon needs and priorities.