Ambiguous expert knowledge under increasing hydroclimatic extremes: Lessons from risk perception in an agricultural region in transition

Over the preceding decades the Western French basins of the Sèvre-Niortaise, and the lower Vienne rivers have seen a decrease of summer precipitation and an increase in drought frequency and severity. The region's land use regime is dominated by intensive agricultural production, with a significant number of farmers relying on irrigation to compensate for prolonged periods of summer drought and to reduce economic uncertainty. Due to the complex repercussions of intensifying droughts for all sectors in the region, the uncertainty of the future scale of the problem, and on-going debates revealing ambiguities about the exact nature of the problem, the concept of systemic risk can be applied to understand the issue facing the region.

In such a context, it has yet to be investigated if and how systems thinking is integrated in expert knowledge and how these lessons can help to guide risk governance for emerging hydroclimatic extremes, both in agricultural contexts and beyond. This contribution seeks to fill this gap in understanding by exploring experts’ perceptions and elucidating the different narratives and conceptualizations that exist between sectors and individuals working in expert roles. To gain these insights in the region of interest, participatory modelling and 26 qualitative interviews were leveraged across stakeholder domains. Contributing experts constitute a comprehensive sample from relevant regional actors and institutions, representing agricultural institutions, river management syndicates, environmental protection, as well as water governance actors.

Results indicate that while experts overall identify growing water scarcity as a problem, differences between domains emerge when it comes to possible solutions. The solution of newly-constructed water reservoirs, favored by the dominant agricultural interests, is seen by members from three out of four expert domains as only one strategy among others. Most advocate for a combination of tools as well as strong conditions for future agricultural water use to ensure transformative momentum to achieve a more water-resilient land management across sectors and land uses, safeguard water quality, and to limit over-reliance on irrigation. Others promote irrigation as the single most effective tool to ensure future agricultural production in the region with water storage as the biggest limiting factor, reducing the larger problem to one of agricultural water management. Furthermore, experts expressed different levels of systems thinking regarding problem diagnosis as well as potential adaptation strategies, pointing to competing narratives about the regional hydrological and land systems, despite access to and use of similar sources of information. This can be explained by a selective, conscious or unconscious, use of information, reinforcing the legitimacy of suggested solutions and thus ultimately shaping the trajectory of policy.

The diverging perceptions and conceptualizations of drought risk found between individual experts and sectors in Western France thus demonstrate the central role of ambiguity and provides lessons how to incorporate expert knowledge to guide adaptation and transformation in contexts of emerging risks with complex, and uncertain characteristics.