A Joint Research Team from Korea University and Stanford University

Develops the World’s First Quantitative Indicator for Water Resource, ‘WSI’ 

— Published in 「Nature Water」… Enhancing the Precision of ESG Water-Related Disclosures

In corporate ESG disclosures, water resources have long been considered an area that is difficult to compare and verify despite their importance. To address this gap, Korea University, Stanford University, and the International ESG Association have jointly developed the world’s first data-driven index capable of quantitatively evaluating corporate water resource management. The research findings will be published in February 2026 in the prestigious journal Nature Water, and are expected to draw significant attention from both academia and industry.

This achievement is the result of a collaborative study conducted by Professor Yong Sik Ok of the Division of Environmental Science and Ecological Engineering at Korea University (President of the International ESG Association), Dr. Yura Cho (Director of the International ESG Association), Professor Jay Hyuk Rhee of Korea University Business School (Director of the Korea University ESG Research Institute and President of the International ESG Association), and Professor William Mitch of the Stanford Doerr School of Sustainability at Stanford University (Fellow of the International ESG Association). 

The Water Sustainability Index (WSI) proposed by the research team was designed to assess corporate water-related activities based on data rather than qualitative descriptions or general commitments. In the past, differences in the methodologies and assumptions used by rating agencies limited comparability among companies. By clearly defining core indicators, WSI has been recognized for significantly enhancing the transparency, consistency, and reproducibility of ESG disclosures. 

The research team also highlighted imbalances in the current disclosure framework. An analysis of data from the London Stock Exchange Group (LSEG) found that among 3,107 companies that received ESG ratings, approximately 40% disclosed greenhouse gas (GHG) emissions, whereas only 26% disclosed total water withdrawal, the most fundamental indicator of water use. Disclosure of recycled water usage was even more limited, empirically demonstrating that water-related information remains a blind spot in corporate evaluation. 

Professor Yong Sik Ok explained, “While greenhouse gas emissions have relatively similar impacts on a global scale, water is a local issue that varies by watershed.” He added, “Evaluation methods that rely on opaque algorithms can produce different results across institutions and may increase concerns about greenwashing.” 

The Water Sustainability Index (WSI) developed by the research team is calculated based on four key water flow indicators: groundwater and surface water withdrawals, wastewater discharge, water consumption, and water reuse. The index also incorporates the ‘water stress’ criteria of the World Resources Institute (WRI), applying double weighting to facilities located in water-stressed regions. This approach provides a practical mechanism that encourages companies to reassess site selection and operational strategies from a water risk perspective. 

This research represents a synergistic collaboration among Professor Yong Sik Ok and Dr. Yura Cho in environmental and ecological engineering, Professor Jay Hyuk Rhee in ESG management and evaluation, and Professor William Mitch of Stanford University, who contributed engineering expertise to the study. It is being recognized as a successful model of global interdisciplinary research, demonstrating how diverse academic disciplines can create meaningful synergy. 

The study also aligns with Korea University’s broader research trajectory of viewing ESG as a core element of strategic decision-making. Korea University Business School has expanded its research base grounded in issues of sustainability management, while the Korea University ESG Research Institute, directed by Professor Jay Hyuk Rhee, has strengthened collaboration with domestic and international academic institutions and organizations to enhance the rigor of disclosure and evaluation frameworks. The development of WSI is particularly significant in that these efforts have converged with environmental and engineering research teams, as well as international collaborators, to produce tangible outcomes. 

Professor Jay Hyuk Rhee stated, “WSI will serve as a standard that enables companies to demonstrate their water management responsibilities to investors and other stakeholders through data-driven metrics.” He added, “Through follow-up research that quantifies and manages water risks across supply chains, including suppliers, we aim to further develop WSI into a global disclosure standard.” 

By shifting the discussion of water issues from narrative-based explanations to data-driven evaluation, this research is expected to serve as a key framework in the development of future global ESG standards.