Earth Observations (EO) systems aim to monitor nearly all aspects of the global Earth environment. Observations of Essential Water Variables (EWVs) together with advanced data assimilation models, could provide the basis for systems that deliver integrated information for operational and policy level decision making that supports the Water-Energy-Food-Nexus (EO4WEF), and concurrently the UN Sustainable Development Goals (SDGs), and UN Framework Convention on Climate Change (UNFCCC). Implementing integrated EO for GEO-WEF (EO4WEF) systems requires resolving key questions regarding the selection and standardization of priority variables, the specification of technologically feasible observational requirements, and a template for integrated data sets. This paper presents a concise summary of EWVs adapted from the GEO Global Water Sustainability (GEOGLOWS) Initiative and consolidated EO observational requirements derived from the GEO Water Strategy Report (WSR). The UN-SDGs implicitly incorporate several other Frameworks and Conventions such as The Sendai Framework for Disaster Risk Reduction; The Ramsar Convention on Wetlands; and the Aichi Convention on Biological Diversity. Primary and Supplemental EWVs that support WEF Nexus & UN-SDGs, and Climate Change are specified. The EO-based decision-making sectors considered include water resources; water quality; water stress and water use efficiency; urban water management; disaster resilience; food security, sustainable agriculture; clean & renewable energy; climate change adaptation & mitigation; biodiversity & ecosystem sustainability; weather and climate extremes (e.g., floods, droughts, and heat waves); transboundary WEF policy.

SARS-CoV-2/COVID-19 propagated rapidly from a local outbreak to global scales with associated multi-trillion $ impact on the international economy and social, economic, and ecological systems. The Pandemic is currently ongoing and key questions have arisen as to what key factors determine its incidence, propagation, and mortality rates. Here, we try to distinguish between concurrent and collocated influences on COVID-19 due to environmental factors (e.g., T, humidity..) compared to policy actions (e.g., lock downs, slowdowns, open/closed businesses, transportation), and social practice (e.g., wearing masks, social distancing). Publicly available data and information from selected countries/regions around the world are used in this initial analysis. Preliminary results suggest that policy actions and social practice have a dominating influence on the propagation and containment (or not) of COVID-19, possibly enabled by or associated with concomitant environmental factors.

The GEOSS Water Strategy–From Observations to Decisions (Lawford et al., 2014) identifies several key water variables as Essential Water Variables (EWVs). This was based on broad meta-surveys (Unninayar et al., 2010) of water-related observational needs for GEO Societal Benefit Aeas (SBAs) that included energy and agriculture among others. This paper summarizes currently defined EWVs required by key research and applications sectors involved in decision support within the Water-Energy-Food (WEF) Nexus. There is a notable overlap between the EWVs and a preliminary assessment of Essential WEF Variables. We also highlight EWVs that are relevant to the indicator monitoring objectives of the UN Sustainable Development Goals (SDGs), and GEOGLOWS priority thematic communities—especially those that overlap with the WEF Nexus. Besides primary EWVs such as precipitation, soil moisture, evapotranspiration and water levels/storage, supplemental EWVs are identified that support the integrated multi-sectoral information needed by WEF decision support applications. Examples of supplemental EWVs include surface meteorology and winds, solar radiation, land use/land cover and vegetation. Both Remote Sensing (RS) platforms and In-Situ observing networks are required to address the broad range of space/time resolutions, accuracies, and data latencies that end-users need. The AGU-2021 is invited to comment on, endorse and/or recommend additional EWVs that should be considered for adoption by GEOGLOWS and the GEO (Group on Earth Observations).

Measuring progress towards achieving the 17 UN Sustainable Development Goals (SDGs) requires the monitoring of indicators developed to assess and quantify changes in the state of natural, social, economic, and environmental systems structures within countries. Aggregated over regions these indicators provide information to decision makers at national, regional and international organizations to support policy actions to ensure the sustainability of available resources. Frequently, the SDG indicators are targeted at specific social or economic subelements; they are not designed to consider the interaction between sectors. Here, we propose an integrated index for the Water-Energy-Food Nexus using a selection of sub-indicators from among the already defined 17 UN Sustainable Development Goals. The use of EO data streams and data assimilation products is proposed as an essential part of the methodology, especially in large parts of the globe where detailed in-situ data are likely to be insufficient or lacking. Once the methodology is validated and tested in a selection of pilot regions, it can be made available to all interested national, regional and international development organizations and programs. Primary Goal: EO/RS WEF-SDG Index to monitor sustainability of natural resources and socio-economic activity.