Advancing extreme event impact attribution: attributing multi-hazard impacts of Hurricane Ida in south Louisiana to past, present, and future climates

Extreme event attribution (EEA) research increasingly studies how the impacts of specific disasters can be linked to climate change. We use a multi-hazard, high resolution, and temporally dynamic framework to study these impacts for Hurricane Ida (2021) in Louisiana. This framework begins with hurricane wind modeling that produces wind fields at warming levels set at 30 year averages for 1971 (i.e. the storm that could have been), 2021 (i.e. the storm that was), and 2071 (i.e. the storm that could be). We then connect these wind fields to storm surge flood models as well to damage functions for both storm surge and wind impacts. Total damages from Hurricane Ida were 19% higher in 2021 than they would have been in 1971 due to historical climate change, and could be 76% higher in 2071 compared to 2021 under projected warming. Damage characteristics vary considerably by hazard (e.g. wind impacts increase at a higher rate than storm surge), time (e.g. greater future increases), space (e.g. climate change’s imprint is higher in the areas with severe or moderate impacts), and by number of affected structures and structure type (e.g. residential structures increase at a higher rate for storm surge). Our findings demonstrate the value of a contextualized, multi-dimensional framework for EEA.