Panel 19 – Multiple hazards and compound/cascading effects

Conveners: Maurizio Mazzoleni and Johanna Mård (Department of Earth Sciences, Uppsala University)

Abstract: Different natural hazards (e.g. floods, droughts, earthquakes, wildfire, etc.), caused by the interaction of multiple hazard drivers in space or time, have a multiplier effect on the risk to society, infrastructure, and the environment, leading to a significant impact is referred to as a ‘compound event’. Recently, they were identified as an important challenge by the World Climate Research Programme (WCRP) ‘Grand Challenge’ on Extremes. For this reason, this panel aims at providing a platform for first understanding current state-of-the-art and recent research findings on compound, cascading, and concurrent events and then discussing reduction and management of compound disaster risks depending on our improved understanding of these causal connections and mechanisms.

Long Abstract: This session focuses on the compound and cascading events, and their impacts on natural hazard risk. Traditionally, risk assessment methods only consider one driver and/or hazard at a time, potentially leading to uncertainty risk evaluation as the processes that cause extreme events often interact and are spatially and/or temporally dependent. However, different natural hazards (e.g. floods, droughts, earthquakes, wildfire, etc.), caused by the interaction of multiple hazard drivers in space or time, have a multiplier effect on the risk to society, infrastructure, and the environment, leading to a significant impact is referred to as a ‘compound event’. For example, recent studies indicate that when river and coastal floods occur at the same time or in quick succession, their impacts could be more devastating than when either occurs separately (Kew et al., 2013; Klerk et al., 2015; Wahl et al., 2015). The need to proper understand compound hazards has been recognized by different studies (e.g., Leonard et al., 2014). Recently, they were identified as an important challenge by the World Climate Research Programme (WCRP) ‘Grand Challenge’ on Extremes. For this reason, this panel aims at providing a platform for first understanding current state-of-the-art and recent research findings on compound, cascading, and concurrent events an then discussing reduction and management of compound disaster risks depending on our improved understanding of these causal connections and mechanisms (Ikeuchi et al., 2017).

We encourage contributions related to all aspects of compound, cascading, and concurrent events, including those that: improve understanding of physical processes; showcase new methodologies, techniques and statistical approaches; and illustrate how including multiple interacting hazards improves risk assessments (Zscheischler et al., 2018). Moreover, we invite panellists which work (both theoretical and empirical) contributes to addressing the following questions: What are the most appropriate theoretical frameworks and supporting tools for risk assessment and attribution that explicitly account for compound events? Which tools and data can be use to better risk management of climate-related impacts? How can we identify the combinations of climate drivers and hazards that collectively lead to changes in risk? Which analysis are required to resolving compound events in climate projections? How can we investigate the changing nature of human activities (such as urbanization, infrastructure, anthropogenic emissions) and their interactions with compound events?

References

Ikeuchi, H., Y. Hirabayashi, D. Yamazaki, S. Muis, P. J. Ward, H. C. Winsemius, M. Verlaan, and S. Kanae (2017), Compound simulation of fluvial floods and storm surges in a global coupled river-coast flood model: Model development and its application to 2007 Cyclone Sidr in Bangladesh, J. Adv. Model. Earth Syst., 9, 1847–1862, doi:10.1002/2017MS000943.

Kew, S. F., F. M. Selten, G. Lenderink, and W. Hazeleger (2013), The simultaneous occurrence of surge and discharge extremes for the Rhine delta, Nat. Hazards Earth Syst. Sci., 13(8), 2017–2029, doi:10.5194/nhess-13-2017-2013.

Klerk, W. J., H. C. Winsemius, W. J. van Verseveld, A. M. R. Bakker, and F. L. M. Diermanse (2015), The co-incidence of storm surges and extreme discharges within the Rhine–Meuse Delta, Environ. Res. Lett., 10(3), 035005, doi:10.1088/1748-9326/10/3/035005.

Leonard, M., S. Westra, A. Phatak, M. Lambert, B. Van den Hurk, K. McInnes, J. Risbey, S. Schuster, D. Jakob, and M. Stafford-Smith (2014), A compound event framework for understanding extreme impacts, WIREs Clim. Change, 5, 113–128, doi:10.1002/wcc.252.

Wahl, T., S. Jain, J. Bender, S. D. Meyers, and M. E. Luther (2015), Increasing risk of compound flooding from storm surge and rainfall for major US cities, Nat. Clim. Change, 5(12), 1093–1097, doi:10.1038/NCLIMATE2736.

Zscheischler, J., Westra, S., van den Hurk, B.J.J.M., Seneviratne, S.I., Ward, P.J., Pitman, A., AghaKouchak, A., Bresch, D.N., Leonard, M., Wahl, T., Zhang, X.Z. (2018), Future climate risk from compound events, Nature Climate Change, 8(6), 469-477.