Improving hydrological climate impact assessments using multirealizations from a global climate model

Many flood risk assessments account for uncertainties in future anthropogenic emissions by considering multiple representative concentration pathways (RCPs). The imperfect knowledge and representation of the climate system is considered with multiple global climate models (GCMs). Yet, uncertainty introduced by incomplete representation of natural variability is also relevant but not always accounted for. A set of realizations provides improved insights in natural variability presented by the GCM. This study explores the potential of using a set of realizations from a single GCM-RCP combination instead of single realizations. We use (subsets of) 16 realizations from EC-Earth for RCP8.5 and focus on three locations along the Rhine. We use a single GCM-RCP combination to avoid the interference of additional sources of uncertainty. We find that projected changes in future river flows highly depend on the realization chosen. Individual ensemble members provide different changes for annual mean flow, extreme flows, and regime shift. By increasing the number of realizations and combining their annual maxima in extreme value analysis, future projections of flow extremes converge. We conclude that a single ensemble realization gives overconfident and possibly erroneous projections. In climate science, this is well studied; however, in flood risk assessments, it is still often neglected

Living with sea-level rise in North-West Europe: Science-policy challenges across scales

Sea-level rise (SLR) confronts coastal societies and stakeholders with increasing hazards and coastal risks with large uncertainties associated to these changes. Adaptation to SLR requires societal and policy decision-making to consider these changing risks, which are in turn defined by socio-economic development objectives and the local societal context. Here, we review some of the key challenges facing governments, stakeholders and scientists in adapting to SLR, and key aspects of successful adaptation, by exploring different approaches to SLR and coastal adaptation planning in three western European countries, the Netherlands, Germany and the United Kingdom. Several common challenges of SLR adaptation emerge across the different settings, including the inherent uncertainty regarding future conditions, the significant social and socio-economic consequences, the consideration and distribution of (residual) risk over communities, and the long legacy of present-day decisions that affect future risk and management options supporting future generations. These challenges are addressed differently in the three countries, e.g. in the governance level at which adaptation is initiated, although common elements also emerge. One common emerging element is adaptive pathways planning, which entails dynamic decision-making that breaks uncertain decisions into manageable elements or steps over time, while keeping options for the future. Another common element is the development of effective local science-policy interfaces, as engagement of local decision-makers and citizens is essential to manage conflicting interests. Lastly, we find that social and communication sciences have great potential to support effective science-policy interfaces, e.g. though identifying societal tipping points. Yet, in decisions on SLR adaptation, insights from these fields are rarely used to date. We conclude that supporting science-policy interactions for adaptation decision-making at relevant (inter)national to local scales through tailored multi-disciplinary scientific assessments is an important way forward for SLR adaptation in Europe

Climate Impact Storylines for Assessing Socio-Economic Responses to Remote Events

Complex interactions involving climatic features, socio-economic vulnerability or responses, and long impact transmissions are associated with substantial uncertainty. Physical climate storylines are proposed as approach to explore complex impact transmission pathways and possible alternative unfolding of event cascades under future climate conditions. These storylines are particularly useful for climate risk assessment for complex domains, including event cascades crossing multiple disciplinary or geographical borders. For an effective role in climate risks assessments, practical guidelines are needed to consistently develop and interpret the storyline event analyses.This paper elaborates on the suitability of physical climate storyline approaches involving climate event induced shocks propagating into societal impacts. It proposes a set of common elements to construct the event storylines. In addition, criteria for their application for climate risk assessment are given, referring to the need for storylines to be physically plausible, relevant for the specific context, and risk-informative.Six examples of varying scope and complexity are presented, all involving the potential climate change impact on European socio-economic sectors induced by remote climate change features occurring far outside the geographical domain of the European mainland. The storyline examples illustrate the application of the proposed storyline components and evaluates the suitability criteria defined in this paper. It thereby contributes to the standardization of the design and application of event-based climate storyline approaches

D1.2 Handbook of multi-hazard, multi-risk definitions and concepts

This report is the first output of Work Package 1: Diagnosis of the MYRIAD-EU project: Handbook of Multi-hazard, Multi-Risk Definitions and Concepts. The aim of the task was to (i) acknowledge the differences and promote consistency in understanding across subsequent work packages in the MYRIAD-EU project, (ii) improve the accessibility of our work to a broad array of stakeholders and (iii) strengthen consensus across the hazard and risk community through a common understanding of multi-hazard, multi-risk terminology and concepts. The work encompassed a mixed-methods approach, including internal consultations and data-generating exercises; literature reviews; external stakeholder engagement; adopting and building on a rich existing body of established glossaries. 140 terms are included in the glossary, 102 related to multi-hazard, multi-risk, disaster risk management and an additional 38 due to their relevance to the project, acknowledging the need for a common understanding amongst an interdisciplinary project consortium. We also include extended definitions related to concepts particularly of relevance to this project deliverable, including ‘multi-hazard’, ‘hazard interrelationships’, ‘multi-risk’ and ‘direct and indirect loss and risk’. Underpinned by a literature review and internal consultation, we include a specific section on indicators, how these might be applied within a multi-hazard and multi-risk context, and how existing indicators could be adapted to consider multi-risk management. We emphasise that there are a number of established glossaries that the project (and risk community) should make use of to strengthen the impact of the work we do, noting in our literature review a tendency in papers and reports to define words afresh. We conclude the report with a selection of key observations, including terminology matters – for all aspects of disaster risk management, for example communication, data collection, measuring progress and reporting against Sendai Framework targets. At the same time, we discuss when is it helpful to include ‘multi-‘ as a prefix, questioning whether part of the paradigm shift needed to successfully address complex challenges facing an interconnected world is through inherently seeing vulnerability, exposure and disaster risk through the lens of multiple, interrelated hazards. We emphasise that there is likely to be an evolution of the terminology throughout the project lifetime as terms are emerge or shift as the project evolves. Finally, we propose a roadmap for developing and testing draft multi-risk indicators in MYRIAD-EU. The WP1 team would like to acknowledge all the contributions of the consortium on this task and the feedback from the External Advisory Board, in particular the chair of the board Virginia Murray, Head of Global Disaster Risk Reduction at the UK Health Security Agency, and the contribution of Jenty Kirsch-Wood, Head of Global Risk Management and Reporting at UNDRR, for her reflections on the findings of this work

A copula-based sensitivity analysis method and its application to a North Sea sediment transport model

This paper describes a novel sensitivity analysis method, able to handle dependency relationships between model parameters. The starting point is the popular Morris (1991) algorithm, which was initially devised under the assumption of parameter independence. This important limitation is tackled by allowing the user to incorporate dependency information through a copula. The set of model runs obtained using latin hypercube sampling, are then used for deriving appropriate sensitivity measures. Delft3D-WAQ (Deltares, 2010) is a sediment transport model with strong correlations between input parameters. Despite this, the parameter ranking obtained with the newly proposed method is in accordance with the knowledge obtained from expert judgment. However, under the same conditions, the classic Morris method elicits its results from model runs which break the assumptions of the underlying physical processes. This leads to the conclusion that the proposed extension is superior to the classic Morris algorithm and can accommodate a wide range of use cases.Petroleum EngineeringApplied Probabilit

Tailored flood risk management: Accounting for socio-economic and cultural differences when designing strategies

Climate change and socio-economic development result in increasing flood risk which challenges flood risk management policy making and practice. Each situation, however, is different and calls for not only understanding the natural context, but also the socio-economic and cultural context. Only then Flood Risk Management strategies can be designed that are not only 1) fit for purpose but also 2) feasible for local implementation and 3) sustainable into the future. Flood consequences that are accepted in some cultures (fatalist), may not be acceptable in other cultures (controlist). This calls for considering the local normative context in order to understand current differences in policy and practice. More importantly, the design of strategic alternatives for Flood Risk Management into the future should consider this socio-economic and cultural context as well because not every society aims for the same goals in the same proportion, nor is equally willing or capable to implement and maintain sophisticated infrastructure and dedicated institutions. Based on literature on cultural theory and national cultures, we hypothesized that acknowledging socio-economic and cultural differences would allow to better appreciate the rationale of current flood risk management policies and practices in different parts of the world. By analysing cases related to Deltares projects abroad, we explored whether these factors explain the main differences observed. Based on this preliminary exploration, we propose a shortlist of factors to consider when designing future flood risk management strategies tailored to local socio-economic and cultural contexts.Policy Analysi

Toward a framework for systemic multi-hazard and multi-risk assessment and management

Summary: In our increasingly interconnected world, natural hazards and their impacts spread across geographical, administrative, and sectoral boundaries. Owing to the interrelationships between multi-hazards and socio-economic dimensions, the impacts of these types of events can surmount those of multiple single hazards. The complexities involved in tackling multi-hazards and multi-risks hinder a more holistic and integrative perspective and make it difficult to identify overarching dimensions important for assessment and management purposes. We contribute to this discussion by building on systemic risk research, especially the focus on interconnectedness, and suggest ways forward for an integrated multi-hazard and multi-risk framework that should be beneficial in real-world applications. In this article, we propose a six-step framework for analyzing and managing risk across a spectrum ranging from single-to multi- and systemic risk

What can COVID-19 teach us about preparing for climate risks in Europe?

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Lessons from COVID-19 for managing transboundary climate risks and building resilience

COVID-19 has revealed how challenging it is to manage global, systemic and compounding crises. Like COVID-19, climate change impacts, and maladaptive responses to them, have potential to disrupt societies at multiple scales via networks of trade, finance, mobility and communication, and to impact hardest on the most vulnerable. However, these complex systems can also facilitate resilience if managed effectively. This review aims to distil lessons related to the transboundary management of systemic risks from the COVID-19 experience, to inform climate change policy and resilience building. Evidence from diverse fields is synthesised to illustrate the nature of systemic risks and our evolving understanding of resilience. We describe research methods that aim to capture systemic complexity to inform better management practices and increase resilience to crises. Finally, we recommend specific, practical actions for improving transboundary climate risk management and resilience building. These include mapping the direct, cross-border and cross-sectoral impacts of potential climate extremes, adopting adaptive risk management strategies that embrace heterogenous decision-making and uncertainty, and taking a broader approach to resilience which elevates human wellbeing, including societal and ecological resilience

Lessons from COVID-19 for managing transboundary climate risks and building resilience

COVID-19 has revealed how challenging it is to manage global, systemic and compounding crises. Like COVID-19, climate change impacts, and maladaptive responses to them, have potential to disrupt societies at multiple scales via networks of trade, finance, mobility and communication, and to impact hardest on the most vulnerable. However, these complex systems can also facilitate resilience if managed effectively. This review aims to distil lessons related to the transboundary management of systemic risks from the COVID-19 experience, to inform climate change policy and resilience building. Evidence from diverse fields is synthesised to illustrate the nature of systemic risks and our evolving understanding of resilience. We describe research methods that aim to capture systemic complexity to inform better management practices and increase resilience to crises. Finally, we recommend specific, practical actions for improving transboundary climate risk management and resilience building. These include mapping the direct, cross-border and cross-sectoral impacts of potential climate extremes, adopting adaptive risk management strategies that embrace heterogenous decision-making and uncertainty, and taking a broader approach to resilience which elevates human wellbeing, including societal and ecological resilience