From scarcity to surplus: the water dichotomy affecting global communities

Abstract In this article, we define the concept of water dichotomy as the simultaneous occurrence of water excess (e.g., floods) and scarcity (e.g., droughts) within the same location. This phenomenon poses significant challenges to health, socio-economic stability, and urban resilience. This paper proposes a framework for understanding and managing water dichotomy, drawing on case studies from the Metropolitan Area of São Paulo, Tokyo, Singapore, Cape Town, and Mexico City, each at different stages of this phenomenon. These cases highlight the importance of decision-making in mitigating or adapting to the dual threats of water excess and scarcity. The study also aligns the concept of water dichotomy with the United Nations 2030 Agenda for Sustainable Development, identifying 32 out of 169 Sustainable Development Goal (SDG) targets that address the water dichotomy impacts in urban areas. The identification of the SDG targets was achieved through an evaluation of whether they related to water dichotomy, a expert consensus assessment and validation by an expert-driven literature review. Our findings provide a foundation for strategies aligned mainly with the Sustainable Development Goals 6 (clean water and sanitation), 11 (sustainable cities and communities), and 13 (climate action) and with recommendations directed at researchers, policymakers, and stakeholders to address the complex challenges of water dichotomy, promoting more resilient and sustainable urban environments.