Unravelling the mutual shaping of hydrological extremes and society will contribute to move forward interdisciplinary efforts that cross boundaries between natural and social sciences. In the context of drought and flood research, interdisciplinary studies originated from the natural sciences (e.g. socio-hydrology) have given more emphasis to the complexity and variability of hydrological processes, while interdisciplinary studies originated from the social sciences (e.g. polical ecology) have given more emphasis to the complexity and variability of social processes. The concept of mutual shaping is intentionally used here to treat both hydrological and social processes with the same level of complexity.
This project has combined hazard-based with vulnerability-based methods to assess risk in a changing climate. For instance, while vulnerability-based methods often do account for diverse hydrological extremes, hazard-based methods for quantitative risk assessment focus on either drought or flood risk. The latter approach does not allow exploring some key dynamics of risk. For example, a number of recent studies have shown that socio-economic changes have been the main driver of increasing flood risk in Africa, while climate has (so far) played a smaller role. Yet, by focusing on flood risk alone, these studies did not consider the hypothesis that climate may have led, in some instances, to longer and more severe drought conditions, which in turn may have changed livelihood patterns, e.g. increased human proximity to rivers, and potentially led to greater exposure or vulnerability to flooding. In other words, it is still largely unexplored how sequences of droughts and floods, can make a difference in the dynamics of hydrological risk. Exploring the sequence effect, which has been one of the goals of this project, is crucial because of the clustering or persistence of droughts and floods, and the relationships between hydrological extremes and inter-annual signals of climate variability, such as El Niño Southern Oscillation. Also, climate research suggests that many regions around the world might experience, in the near future, more prolonged drought conditions followed by extreme flood events. This speaks for the relevance of the project results that have increased our understanding of how human response to drought might exacerbate the impact of flood events, and vice versa.
Lastly, the explanatory models developed in this project open up new opportunities for science. They contribute to ongoing efforts to modelling human adaptation to climate change. They have also been linked to global models, which did not account for the dynamic interplay of society and hydrological extremes, and been used to inform agent-based models. As such, this project has contributed to enrich the fundamental science underpinning water management in a rapidly changing environment.
