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As the adverse impacts of hydrological extremes increase in many regions of the world, a better understanding of the drivers of changes in risk and impacts is essential for effective flood and drought risk management and climate adaptation. However, there is currently a lack of comprehensive, empirical data about the processes, interactions, and feedbacks in complex human-water systems leading to flood and drought impacts. Here we present a benchmark dataset containing socio-hydrological data of paired events, i.e. two floods or two droughts that occurred in the same area. The 45 paired events occurred in 42 different study areas and cover a wide range of socio-economic and hydro-climatic conditions. The dataset is unique in covering both floods and droughts, in the number of cases assessed and in the quantity of socio-hydrological data. The benchmark dataset comprises (1) detailed review-style reports about the events and key processes between the two events of a pair; (2) the key data table containing variables that assess the indicators which characterize management shortcomings, hazard, exposure, vulnerability, and impacts of all events; and (3) a table of the indicators of change that indicate the differences between the first and second event of a pair. The advantages of the dataset are that it enables comparative analyses across all the paired events based on the indicators of change and allows for detailed context- and location-specific assessments based on the extensive data and reports of the individual study areas. The dataset can be used by the scientific community for exploratory data analyses, e.g. focused on causal links between risk management; changes in hazard, exposure and vulnerability; and flood or drought impacts. The data can also be used for the development, calibration, and validation of socio-hydrological models. The dataset is available to the public through the GFZ Data Services (Kreibich et al., 2023, 10.5880/GFZ.4.4.2023.001).

Recent impactful hydrometeorological events, on both the extreme wet and dry side of the spectrum, remind policymakers and citizens that climate change is a reality and that a shift in water management solutions is required. A selection of policy-shaping events in the Netherlands shows that both floods and droughts have occurred historically and continue to occur, causing significant impacts and challenges for water resources management. For decades, water management in the Netherlands has focused on implementing flood prevention policies, mostly prompted by specific events. The occurrence of droughts did not lead to comparable significant transitions in water management. The bias toward adaptation measures on the wet part of the spectrum (i.e., floods), increases vulnerability to dry extremes (i.e., droughts) as experienced in 2018–2020 and 2022. A required long-term, integral vision to rethink the existing water management system is challenging as droughts and floods act on different time scales. Furthermore, there is a fierce competition for land use and water use functions. ‘Transformation pathways’, applied across the full flood–drought spectrum, could provide a valuable framework in the development toward a sustainable management of water resources, involving stakeholders for just and equitable transitions and translating long-term visions into pathways for action.

Uncertainties in the rate and magnitude of sea-level rise (SLR) complicate decision making on coastal adaptation. Large uncertainty arises from potential ice mass-loss from Antarctica that could rapidly increase SLR in the second half of this century. To deal with uncertain SLR, the Netherlands has adopted an adaptive pathways strategy. Monitoring of new insights on climatic risks and societal developments is an essential ingredient of this strategy. The implications of SLR may be existential for a low-lying country as the Netherlands, and warrant exploration of high- impact low-likelihood scenarios. Therefore, a study was initiated to analyse the implications of storylines leading to extreme SLR for the current adaptive plan. This paper reports on the process and findings of uncertain high SLR consequences on flood, drought, and coastal management in the Netherlands, and discusses implications for coastal adaptation considering timescales of adaptation including lifetime of decisions and their lead-in time for preparation and implementation. We find that for extreme SLR transformative measures are needed, not only because of the unanticipated sea level values that are inconsistent with current strategy boundary conditions, but also because of high SLR rates that challenge adaptation. Anticipating deeply uncertain high SLR helps to enable timely adaptation and to appreciate the value of emission reduction and monitoring of the Antarctica contribution to SLR.

We thank the authors, Brunella Bonaccorso and Karsten Arnbjerg-Nielsen for their constructive contributions to the discussion about the attribution of changes in drought and flood impacts. We appreciate that they support our opinion, but in particular their additional new ideas on how to better understand changes in impacts. It is great that they challenge us to think a step further on how to foster the collection of long time series of data and how to use these to model and project changes. Here, we elaborate on the possibility to collect time series of data on hazard, exposure, vulnerability and impacts and how these could be used to improve e.g. socio-hydrological models for the development of future risk scenarios.

For the development of sustainable, efficient risk management strategies for the hydrological extremes of droughts and floods, it is essential to understand the temporal changes of impacts, and their respective causes and interactions. In particular, little is known about changes in vulnerability and their influence on drought and flood impacts. We present a fictitious dialogue between two experts, one in droughts and the other in floods, showing that the main obstacles to scientific advancement in this area are both a lack of data and a lack of commonly accepted approaches. The drought and flood experts “discuss” available data and methods and we suggest a complementary approach. This approach consists of collecting a large number of single or multiple paired-event case studies from catchments around the world, undertaking detailed analyses of changes in impacts and drivers, and carrying out a comparative analysis. The advantages of this approach are that it allows detailed context- and location-specific assessments based on the paired-event analyses, and reveals general, transferable conclusions based on the comparative analysis of various case studies. Additionally, it is quite flexible in terms of data and can accommodate differences between floods and droughts.

The concept of resilience is used by many in different ways: as a scientific concept, as a guiding principle, as inspirational ‘buzzword’, or as a means to become more sustainable. Next to the academic debate on meaning and notions of resilience, the concept has been widely adopted and interpreted in policy contexts, particularly related to climate change and extreme weather events. In addition to having a positive connotation, resilience may cover aspects that are missed in common disaster risk management approaches. Although the precise definition of resilience may remain subject of discussion, the views on what is important to consider in the management of extreme weather events do not differ significantly. Therefore, this paper identifies the key implications of resilience thinking for the management of extreme weather events and translates these into five practical principles for policy making., Policy Analysis