Abstract
Water scarcity has become a major constraint to socio-economic development and a threat to the achievement of the Sustainable Development Goals. Since Marlin Falkenmark first proposed the concept and assessment method of water scarcity in the 1980s, water scarcity assessment has evolved for some 40 years. Most of the progress made in the last few decades has been on the quantification of water availability and use by applying spatially explicit models.
In recent years, water scarcity assessment has experienced an evolutionary advance from a one-dimensional model emphasizing only quantity-induced water scarcity to a two-dimensional model (considering both quantity-induced and quality-induced water scarcity), and towards a three-dimensional (3D) model (or 3D water scarcity theory) that considers water quantity, water quality, and environmental flow requirements simultaneous.
In this presentation, I will demonstrate the 3D water scarcity theory and elaborate its concepts, principles, and core methods. The quantity-induced water scarcity is assessed based on the ratio of blue water footprint to water availability, and the quality-induced water scarcity is quantified by comparing gray water footprint (the amount of water required to dilute pollutants in wastewater sufficiently to meet environmental water quality standards) with locally available water resources. Environmental flow requirements are integrated in the assessment of water availability based on the characteristics of climatic and hydrological conditions. Hence, the 3D water scarcity theory can incorporate water quantity, water quality, and ecosystem water requirements comprehensively in the assessment.
The 3D water scarcity assessment requires advanced methods to quantify water footprint, water resources and nutrient cycles, and sustainable water use. I will show the methods, tools and approaches developed to support such an assessment. They include but are not limited to the GEPIC model for water footprint assessment, the WAYS model for water resources assessment, the economic input-output model to investigate the role of virtual water in re-shaping the spatial patterns of water scarcity. I will also demonstrate how to apply the knowledge gained from the 3D water scarcity assessment for successful restorations of degraded rivers.
Bio
Junguo Liu is a Chair Professor and Associate Dean at the Southern University of Science and Technology in China, and a Senior Guest Research Scholar at the International Institute for Applied Systems Analysis (IIASA) in Austria. Recognized as a highly cited researcher and elected member of Academia Europaea (The Academy of Europe), he serves as the President of the Society for Ecological Rehabilitation of Beijing, the Vice President of the Chinese National Commission for the International Association of Hydrological Sciences (IAHS), and the Chair of the Union of Societies for Ecological Restoration and Environmental Protection. As author of over 260 scholarly publications (including articles in Science, Nature and PNAS) and 7 books, his research involves several areas including hydrology and water resources, global environmental change, and ecological restoration. He is/was an editor-in-chief, editor, associate editor or board member of 10 scientific journals. Liu is a Lead Author of the Intergovenmental Panel on Climate Change (IPCC) Sixth Assessment Report, and an expert consultant for UN-Water, UNEP, FAO, Alliance for Global Water Adaptation, and the Water Footprint Network. He is a Highly Cited Researcher from Clarivate for Cross-Field performance, and was listed in the Reuters Hot List of the World’s 1,000 Top Climate Scientists, Stanford University's World's Top 2% Scientists, and Elsevier Highly Cited Chinese Researchers. His awards include: AGU’s Paul A. Witherspoon Lecture, the World Academy of Sciences (TWAS) Award, the Communication Award of the International Society for Ecological Restoration (SER), and EGU’s Outstanding Young Scientist Award, and National Distinguished Young Scientist Award of China by the National Natural Science Foundation of China. He is a fellow of the American Association for the Advancement of Science (AAAS), the Royal Meteorological Society (UK) and the Royal Geographical Society (UK).
