Broadening the scope of anthropogenic influence in extreme event attribution

December 2, 2024

A new paper titled “Broadening the scope of anthropogenic influence in extreme event attribution” led by Aglaé Jézéquel, with multiple co-authors including CW3E’s Anna Wilson, was recently published in Environmental Research: Climate. Jézéquel proposes a multidimensional framework for Extreme Event Attribution (EEA) built on the framework proposed by Bastos et al. (2023) to study compound eco-climatic events. The new framework aims to bridge the EEA and Disaster Risk Reduction (DRR) communities by considering the contributions of both anthropogenic climate change and the structure of human societies to the impacts of extreme weather events. Jézéquel uses the new framework in this paper to examine five case studies, including California droughts and the Forecast Informed Reservoir Operations (FIRO) system as an adaptation strategy. This supports CW3E’s 2019-2024 Strategic Plan by documenting the potential benefits of using the best available science to inform reservoir operations.

The broader framework proposed by Jézéquel et al. includes attributions of disaster impacts to exposure and vulnerability. In the case study involving FIRO, Jézéquel et al. discusses how a model could be used to compare Lake Mendocino storage, with and without FIRO, and with and without climate change (Figure 1, Figure 6 from Jézéquel et al. 2024). The counterfactual world without the FIRO adaptation strategy displays a lower water supply in the drought year of water year 2020. By using the proposed framework and synthetic weather forecasts, tests could be run to determine how inflows to Lake Mendocino would be impacted by climate change, and whether the FIRO system would be robust to a counterfactual world with higher concentrations of greenhouse gases. Jézéquel also discusses how the framework could be used for analyzing the 2021-2022 Kenyan drought; the 2013-2015 marine heatwave in the northeast Pacific; the 2017 forest fires in Portugal; and Acqua Alta (flooding) events in Venice and evaluation of adaptation strategies.

Figure 1. (Figure 6 from Jézéquel et al. 2024) Partial causality chart for the 2020 California drought modulated by the use of the FIRO system.

Bastos, A., Sippel, S., Frank, D., Mahecha, M. D., Zaehle, S., Zscheischler, J., & Reichstein, M. (2023). A joint framework for studying compound ecoclimatic events. Nature Reviews Earth & Environment, 4, 333-350. https://doi.org/10.1038/s43017-023-00410-3

Jézéquel, A., Bastos, A., Wilson, A. M., Ramos, A. M., Shepherd, T. G., Stuart-Smith, R., Kimutai, J., Moemken, J., Zscheischler, J., Faranda, D., Lehner, F., Le Grix, N., Sippel, S., Bevacqua, E., Rufat, S., D’Andrea, F., Lloyd, E. A., & Van Loon, A. F. (2024). Broadening the scope of anthropogenic influence in extreme event attribution Environmental Research: Climate, 3, 042003. https://doi.org/10.1088/2752-5295/ad7527