Vulnerability and Adaptation Pathways

Coastal Adaptation Planning> Vulnerability and Adaptation Pathways


Los Angeles County’s geography, ecology, and communities are highly variable, as are its climate impacts and risks. The region is impacted by a variety of threats, such as bluff erosion, sea level rise, wildfire, saltwater intrusion, water availability, and water quality, amongst others. Similarly, L.A. County also faces extreme variation in social and economic factors, including disparities in income, education, and employment opportunities. Anticipating this risk requires comprehensive vulnerability assessments that consider ecological, social, economic, and cultural factors and examines how these components might be impacted by specific climate risks. 

However, sea level rise and uncertainty in its projections pose a major challenge to flood risk management and adaptation investments. Adaptation pathways can meet this challenge.An adaptation pathway is defined as the collection of measures (e.g., beach nourishment, dune restoration, flood-proofing buildings, and levees) required to lower flood risk. The aim of using different adaptation pathways is to enable a transition from one methodology to another over time. These pathways address uncertainty in future projections, allowing for flexibility among policies and potentially spreading the costs over time. 

USC Sea Grant works to support and inform comprehensive vulnerability assessments and evaluations of adaptation strategies for coastal adaptation that holistically addresses community needs.

National Centers for Coastal Ocean Science (NCCOS): 

Indicators and participatory processes: a framework for assessing integrated climate vulnerability and risk as applied in Los Angeles County, California

  • Citation: Fleming, C.S., Regan, S.D., Freitag, A. et al. Indicators and participatory processes: a framework for assessing integrated climate vulnerability and risk as applied in Los Angeles County, California. Nat Hazards 115, 2069–2095 (2023). https://doi.org/10.1007/s11069-022-05628-w
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  • Description: Climate vulnerability research is enhanced by stakeholder engagement as coastal communities are increasingly vulnerable to climate-driven impacts, yet these impacts are rarely evenly distributed across space and stakeholder feedback is not always well incorporated into the process. While often used in applied management applications, integrated spatially explicit assessments of multi-faceted vulnerability and hazard less commonly appear in the scientific literature, especially those that are transferable across geographies and risk metrics. Since many geographies lack an integrated, stakeholder-driven assessment of multiple hazards and vulnerabilities within the same assessment, scientists with the National Oceanic and Atmospheric Administration’s National Centers for Coastal Ocean Science developed a transferable and integrated community vulnerability assessment framework (Framework) that relies primarily upon available secondary data and is supplemented with stakeholder-derived primary data. Using blended approaches in stakeholder engagement, we present the Framework’s six methodological steps as recently applied in Los Angeles County, California: iterative partner engagement, indicator and index development, vulnerability assessment, hazard assessment, risk assessment, and reengagement for adaptation action. We conclude that boundary-spanning organizations such as Sea Grant Extension programs can play a crucial role in participatory science and stakeholder needs assessments, and emphasize the need for continued stakeholder engagement in climate science.


Assessing the Geographic Variability in Vulnerability to Climate Change and Coastal Hazards in Los Angeles County, California

  • Citation: Fleming, C.S., S.D. Regan, A. Freitag, and H. Burkart. 2020. Assessing the Geographic Variability in Vulnerability to Climate Change and Coastal Hazards in Los Angeles County, California. NOAA Technical Memorandum NOS NCCOS 275. Silver Spring, MD. 172 pp. DOI: 10.25923/mgca-hc06
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  • Description: This report presents background, methodology, and findings from the third application of the National Centers for Coastal Ocean Science’s (NCCOS) Integrated Vulnerability Assessment Framework. Building upon previous work done in the Chesapeake Bay, the Framework was applied in Los Angeles (L.A.) County, California. The overarching goals of the project were to: 1) provide partners with the ability to more easily understand the complexities of overall vulnerability and risk within their region, thereby leading to informed management action; and 2) expand upon previous iterations of the Framework in a new geography with variability in demographics, ecology, and climate concerns. 

University of Amsterdam: 

Pathways to resilience: adapting to sea level rise in Los Angeles

  • Citation: Aerts, J. C., Barnard, P. L., Botzen, W. , Grifman, P. , Hart, J. F., Moel, H. , Mann, A. N., Ruig, L. T. and Sadrpour, N. (2018), Pathways to resilience: adapting to sea level rise in Los Angeles. Ann. N.Y. Acad. Sci., 1427: 1-90. doi:10.1111/nyas.13917
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  • Description: Los Angeles (LA) County's coastal areas are highly valued for their natural benefits and their economic contributions to the region. While LA County already has a high level of exposure to flooding (e.g. people, ports, and harbors), climate change and sea level rise will increase flood risk; anticipating this risk requires adaptation planning to mitigate social, economic, and physical damage. This study provides an overview of the potential effects of sea level rise on coastal LA County and describes adaptation pathways and estimates associated costs in order to cope with sea level rise. An adaptation pathway in this study is defined as the collection of measures (e.g., beach nourishment, dune restoration, flood‐proofing buildings, and levees) required to lower flood risk. The aim of using different adaptation pathways is to enable a transition from one methodology to another over time. These pathways address uncertainty in future projections, allowing for flexibility among policies and potentially spreading the costs over time. Maintaining beaches, dunes, and their natural dynamics is the foundation of each of the three adaptation pathways, which address the importance of beaches for recreation, environmental value, and flood protection. In some scenarios, owing to high projections of sea level rise, additional technical engineering options such as levees and sluices may be needed to reduce flood risk. The research suggests three adaptation pathways, anticipating a +1 ft (0.3 m) to +7 ft (+2 m) sea level rise by year 2100. Total adaptation costs vary between $4.3 and $6.4 bn, depending on measures included in the adaptation pathway.

An economic evaluation of adaptation pathways in coastal mega cities: An illustration for Los Angeles

  • Citation: Ruig, L. T., Barnard, P. L., Botzen, W., Grifman, P., Hart, J. F., Moel, H., Sadrpour, N. and Aerts, J. C. (2019), An economic evaluation of adaptation pathways in coastal mega cities: An illustration for Los Angeles. Sci Total Environ., 678:647-659. doi:10.1016/j.scitotenv.2019.04.308
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  • Description: Sea level rise and uncertainty in its projections pose a major challenge to flood risk management and adaptation investments in coastal mega cities. This study presents a comparative economic evaluation method for flood adaptation measures, which couples a cost-benefit analysis with the concept of adaptation pathways. Our approach accounts for uncertainty in sea level rise projections by allowing for flexibility of adaptation strategies over time. Our method is illustrated for Los Angeles County which is vulnerable to flooding and sea level rise. Results for different sea level rise scenarios show that applying adaptation pathways can result in higher economic efficiency (up to 10%) than individual adaptation strategies, despite the loss of efficiency at the initial strategy. However, we identified 'investment tipping points', after which a transition could decrease the economic efficiencies of a pathway significantly. Overall, we recommend that studies evaluating adaptation strategies should integrate cost-benefit analysis frameworks with adaptation pathways since this allows for better informing decision makers about the robustness and economic desirability of their investment choices.
     
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