Uncovering the Dynamics of Multi‐Sector Impacts of Hydrological Extremes: A Methods Overview

Abstract

Hydrological extremes, such as droughts and floods, can trigger a complex web of compound and cascading impacts (CCI) due to interdependencies between coupled natural and social systems. However, current decision‐making processes typically only consider one impact and disaster event at a time, ignoring causal chains, feedback loops, and conditional dependencies between impacts. Analyses capturing these complex patterns across space and time are thus needed to inform effective adaptation planning. This perspective paper aims to bridge this critical gap by presenting methods for assessing the dynamics of the multi‐sector CCI of hydrological extremes. We discuss existing challenges, good practices, and potential ways forward. Rather than pursuing a single methodological approach, we advocate for methodological pluralism. We see complementary or even convergent roles for analyses based on quantitative (e.g., data‐mining, systems modeling) and qualitative methods (e.g., mental models, qualitative storylines). The data‐driven and knowledge‐driven methods provided here can serve as a useful starting point for understanding the dynamics of both high‐frequency CCI and low‐likelihood but high‐impact CCI. With this perspective, we hope to foster research on CCI to improve the development of adaptation strategies for reducing the risk of hydrological extremes.

Comment on egusphere-2024-650 from Kelly Helm Smith

“…This analysis opens space for further research in other regions of the world where drought impacts are also monitored, for instance the USA 1 and Central and Eastern Europe 2 . This type of analysis should be conducted to assess policy effectiveness to deal with drought impacts, and that can only be done with continual drought impacts monitoring, which is unfortunately lacking in most of the world (Smith et al, 2023).…”

Comment on egusphere-2024-650, Kelly Smith

“…This analysis opens space for further research in other regions of the world where drought impacts are also monitored, for instance the USA 1 and Central and Eastern Europe 2 . This type of analysis should be conducted to assess policy effectiveness to deal with drought impacts, and that can only be done with continual drought impacts monitoring, which is unfortunately lacking in most of the world (Smith et al, 2023).…”

Characterizing the multisectoral impacts of future global hydrologic variability

“…Conversely, when variance is overestimated like for the Mekong basin (figure 2(c)), the model predicts that the lowest flow years are more severe than the reference and that there is more water available in high flow years than is actually the case. Both types of error in variance can lead to poor understanding of hydrologic extremes, which are linked to some of the most societally consequential outcomes across sectors [37][38][39]. This motivates the need for stochastic models that can better represent uncertainty in the runoff prediction while also correcting for model bias and misrepresentation of variance.…”