New Publication in the Proceedings of the National Academy of Sciences

Mar 30, 2021 | News, Publications | 0 comments

A Coupled Human-Natural System Analysis of Freshwater Security Under Climate and Population Change

Professor Josue Medellin-Azuara was mentioned in a UC Merced Newsroom article regarding his recent publication.

Josue Medellin-AzuaraThe Paper

Civil and Environmental Engineering Professor Josué Medellín-Azuara is part of an international team of researchers who conducted a systems analysis on water security in Jordan the findings of which were published in Proceedings of the National Academy of Sciences. The paper, titled “A Coupled Human-Natural System Analysis of Freshwater Security Under Climate and Population Change” examines Jordan’s water crisis due to increased water use, population growth, climate change and other factors. The study finds that in the absence of demand management and supply interventions, and major reforms in the water sector, nearly 90 percent of the lower income population water security is under threat.


Limited water availability, population growth, and climate change have resulted in freshwater crises in many countries. Jordan’s situation is emblematic, compounded by conflict-induced population shocks. Integrating knowledge across hydrology, climatology, agriculture, political science, geography, and economics, we present the Jordan Water Model, a nationwide coupled human–natural-engineered systems model that is used to evaluate Jordan’s freshwater security under climate and socioeconomic changes. The complex systems model simulates the trajectory of Jordan’s water system, representing dynamic interactions between a hierarchy of actors and the natural and engineered water environment. A multiagent modeling approach enables the quantification of impacts at the level of thousands of representative agents across sectors, allowing for the evaluation of both systemwide and distributional outcomes translated into a suite of water-security metrics (vulnerability, equity, shortage duration, and economic well-being). Model results indicate severe, potentially destabilizing, declines in freshwater security. Per capita water availability decreases by approximately 50% by the end of the century. Without intervening measures, >90% of the low-income household population experiences critical insecurity by the end of the century, receiving <40 L per capita per day. Widening disparity in freshwater use, lengthening shortage durations, and declining economic welfare are prevalent across narratives. To gain a foothold on its freshwater future, Jordan must enact a sweeping portfolio of ambitious interventions that include large-scale desalinization and comprehensive water sector reform, with model results revealing exponential improvements in water security through the coordination of supply- and demand-side measures.