Impact Webs: a novel conceptual modelling approach for characterising and assessing complex risks

<p>Identifying, characterising, and assessing the complex nature of risks are vital to realise the expected outcome of the Sendai Framework for Disaster Risk Reduction. Over the past two decades, the conceptualisation of risk has evolved from a hazard-centric perspective to one that integrates...

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Main Authors: E. Sparkes, D. Cotti, A. Valdiviezo Ajila, S. E. Werners, M. Hagenlocher
Format: Article
Language:English
Published: Copernicus Publications 2025-07-01
Series:Hydrology and Earth System Sciences
Online Access:https://hess.copernicus.org/articles/29/3297/2025/hess-29-3297-2025.pdf
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author E. Sparkes
D. Cotti
A. Valdiviezo Ajila
S. E. Werners
S. E. Werners
M. Hagenlocher
author_facet E. Sparkes
D. Cotti
A. Valdiviezo Ajila
S. E. Werners
S. E. Werners
M. Hagenlocher
author_sort E. Sparkes
collection DOAJ
description <p>Identifying, characterising, and assessing the complex nature of risks are vital to realise the expected outcome of the Sendai Framework for Disaster Risk Reduction. Over the past two decades, the conceptualisation of risk has evolved from a hazard-centric perspective to one that integrates dynamic interactions between hazards, exposure, system vulnerabilities, and responses. This calls for a need to develop tools and methodologies that can account for such complexity in risk assessments. However, existing risk assessment approaches are hitting limits to tackle such complexity. To this end, we developed a novel complex-risk assessment methodology named Impact Webs, inspired by a conceptual risk modelling approach named Climate Impact Chains that integrates aspects of various other conceptual models used in risk assessments, such as causal loop diagrams and fuzzy cognitive mapping. Impact Webs are developed in a participatory manner with stakeholders and characterise and map interconnections between risks, their underlying hazards, risk drivers, root causes, and responses to risks, as well as direct and cascading impacts across multiple systems and at various scales. In this methodological paper, we show how we developed the Impact Web methodology, including how we derived which elements to include in the model, demonstrating the logic and visual output and listing the steps we followed for construction. As proof of concept, we present the results of a complex-risk assessment in Guayaquil, Ecuador, which investigated how COVID-19, concurrent hazards, and responses propagated risks and impacts across sectors and systems during the pandemic. Reflecting on the utility of Impact Webs, application in case studies demonstrates the methodology's usefulness for understanding complex cause–effect relationships and informing decision-making across different scales. The participatory process of developing Impact Webs with stakeholders uncovers critical elements in systems at risk, and helps to evaluate co-benefits and trade-offs of decisions by uncovering how the outcomes of disaster risk management practices affect people, organisations, and sectors differently. Offering a system-wide perspective for modelling, Impact Webs stand as a valuable methodological contribution for complex-risk assessment.</p>
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spelling doaj-art-821279e755ff4ef0abb257f764fa67042025-08-20T03:56:50ZengCopernicus PublicationsHydrology and Earth System Sciences1027-56061607-79382025-07-01293297331310.5194/hess-29-3297-2025Impact Webs: a novel conceptual modelling approach for characterising and assessing complex risksE. Sparkes0D. Cotti1A. Valdiviezo Ajila2S. E. Werners3S. E. Werners4M. Hagenlocher5Vulnerability Assessment, Risk Management and Adaptive Planning division, United Nations University – Institute for Environment and Human Security, Bonn, GermanyVulnerability Assessment, Risk Management and Adaptive Planning division, United Nations University – Institute for Environment and Human Security, Bonn, GermanyFacultad de Ingeniería en Ciencias de la Tierra, Escuela Superior Politécnica del Litoral, Guayaquil, EcuadorVulnerability Assessment, Risk Management and Adaptive Planning division, United Nations University – Institute for Environment and Human Security, Bonn, GermanyEarth Systems and Global Change group, Wageningen University & Research, Wageningen, the NetherlandsVulnerability Assessment, Risk Management and Adaptive Planning division, United Nations University – Institute for Environment and Human Security, Bonn, Germany<p>Identifying, characterising, and assessing the complex nature of risks are vital to realise the expected outcome of the Sendai Framework for Disaster Risk Reduction. Over the past two decades, the conceptualisation of risk has evolved from a hazard-centric perspective to one that integrates dynamic interactions between hazards, exposure, system vulnerabilities, and responses. This calls for a need to develop tools and methodologies that can account for such complexity in risk assessments. However, existing risk assessment approaches are hitting limits to tackle such complexity. To this end, we developed a novel complex-risk assessment methodology named Impact Webs, inspired by a conceptual risk modelling approach named Climate Impact Chains that integrates aspects of various other conceptual models used in risk assessments, such as causal loop diagrams and fuzzy cognitive mapping. Impact Webs are developed in a participatory manner with stakeholders and characterise and map interconnections between risks, their underlying hazards, risk drivers, root causes, and responses to risks, as well as direct and cascading impacts across multiple systems and at various scales. In this methodological paper, we show how we developed the Impact Web methodology, including how we derived which elements to include in the model, demonstrating the logic and visual output and listing the steps we followed for construction. As proof of concept, we present the results of a complex-risk assessment in Guayaquil, Ecuador, which investigated how COVID-19, concurrent hazards, and responses propagated risks and impacts across sectors and systems during the pandemic. Reflecting on the utility of Impact Webs, application in case studies demonstrates the methodology's usefulness for understanding complex cause–effect relationships and informing decision-making across different scales. The participatory process of developing Impact Webs with stakeholders uncovers critical elements in systems at risk, and helps to evaluate co-benefits and trade-offs of decisions by uncovering how the outcomes of disaster risk management practices affect people, organisations, and sectors differently. Offering a system-wide perspective for modelling, Impact Webs stand as a valuable methodological contribution for complex-risk assessment.</p>https://hess.copernicus.org/articles/29/3297/2025/hess-29-3297-2025.pdf
spellingShingle E. Sparkes
D. Cotti
A. Valdiviezo Ajila
S. E. Werners
S. E. Werners
M. Hagenlocher
Impact Webs: a novel conceptual modelling approach for characterising and assessing complex risks
Hydrology and Earth System Sciences
title Impact Webs: a novel conceptual modelling approach for characterising and assessing complex risks
title_full Impact Webs: a novel conceptual modelling approach for characterising and assessing complex risks
title_fullStr Impact Webs: a novel conceptual modelling approach for characterising and assessing complex risks
title_full_unstemmed Impact Webs: a novel conceptual modelling approach for characterising and assessing complex risks
title_short Impact Webs: a novel conceptual modelling approach for characterising and assessing complex risks
title_sort impact webs a novel conceptual modelling approach for characterising and assessing complex risks
url https://hess.copernicus.org/articles/29/3297/2025/hess-29-3297-2025.pdf
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