Hydrological Extremes and Human Society

Abstract:

Economic losses caused by hydrological extremes, i.e. droughts and floods, are dramatically increasing in many regions of the world. In the Anthropocene, humans significantly impact (deliberately or not) the frequency, magnitude and spatial distribution of hydrological extremes. Meanwhile, humans also respond (formally or informally) to droughts and floods, as shown by demographic, policy and institutional changes often associated with the occurrence of extreme events. Hydrological studies have widely investigated human impacts on droughts and floods, while conversely social studies have broadly explored human responses to extreme events. Yet, the complex dynamics of risk resulting from their interplay, i.e. both impacts and responses, have remained poorly understood. As a result, strategies, policies and measures of water management (and disaster risk reduction) often lead to unintended consequences in the long-term or uneven distributions of costs and benefits.

Here I show recent research about the mutual shaping of hydrological extremes and society. This interdisciplinary work is based on the development and testing of sociohydrological models as competing hypotheses about the way in which humans impact, and respond to, droughts and floods. These models are developed and tested through empirical analyses of specific case studies as well as global investigations across multiple sites, taking advantage of the current proliferation of worldwide datasets. By integrating theoretical and empirical methods, we are starting to address the gap of fundamental knowledge about undesired dynamics of risk generated by the interplay between floods, droughts and humans. This unravelling of sociohydrological phenomena has an important role to play in informing policy processes and assisting communities, governments and private actors to reduce hydrological risk while meeting the Sustainable Development Goals, the societal grand challenge of our time.