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PRELIMINARY CLIMATE VULNERABILITY ASSESSMENT RESULTS
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RECOMMENDATION
Review preliminary results of the Climate Vulnerability Assessment (CVA) for the Stockton Comprehensive Climate Action and Adaptation Plan (CCAAP) thus far.
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Summary
The technical consultant, AECOM, will provide an overview of the Climate Vulnerability Assessment and present preliminary results that will be included in the CCAAP as required by the Adaptation Planning Grant Program (APGP).
DISCUSSION
Background
The Climate Vulnerability Assessment (CVA) describes projected climate change and impacts on San Joaquin County and, specifically, the City of Stockton’s critical facilities, transportation infrastructure, utility infrastructure, natural systems, and socially vulnerable communities. Rising global temperatures are driving significant shifts in climate patterns, leading to more frequent and intense heat events. These changes also trigger secondary impacts, including extreme precipitation, prolonged droughts, inland flooding, sea level rise, and increased wildfire risk.
To inform the Climate Vulnerability Assessment, the technical team compiled a comprehensive list of climate hazards based on historical events and an analysis of future climate projections for the Stockton region. The Climate Vulnerability Assessment uses climate projections from California’s Fourth Climate Change Assessment (Fourth Assessment), which are downscaled from global climate models (GCM) published as part of the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (AR5).
Global climate models are complex computer models that represent physical processes part of the Earth’s atmosphere, oceans, physical land, and polar regions to model future climate trends based on global GHG emission concentrations. Basically, they tell us what the future global warming, sea level rise, and other associated climate impacts (drought, precipitation, etc.) will most likely be based on trends in future greenhouse gas emissions. In this project we’re using climate model data that has been downscaled or localized to California by the State of California.
To support local planning, the Stockton Climate Vulnerability Assessment uses mid-century climate projections for the Representative Concentration Pathway 8.5 scenario, which represents a high-emissions scenario where emissions continue to rise throughout the 21st century due to continued dependence on fossil fuels and rapid economic growth and energy use. By using projections from this scenario, planners can better understand extreme conditions, identify vulnerabilities, and mitigate potential risks, making representative concentration pathway (RCP) 8.5 a widely accepted standard in climate adaptation planning.
This analysis focuses on extreme heat, drought, and flooding. It does not consider wildfire, which was determined to pose relatively little risk to the City of Stockton. The Climate Vulnerability Assessment does not include wildfire smoke, whose future occurrence depends on highly localized factors such as wildfire location and wind direction, and thus its future extent and severity cannot be predicted in a climate model. However, adaptation strategies will consider wildfire smoke.
Extreme heat, precipitation, and drought projections are sourced from Cal-Adapt, which is developed by the State of California, to provide locally downscaled climate projections for cities and counties in California. Flood map data is sourced from the Federal Emergency Management Agency, which provides the most accurate estimate of flood risk through its topographical mapping.
Assets analyzed in the Climate Vulnerability Assessment include transportation assets (roads, railways, the Port of Stockton, bike routes), critical buildings (schools, community centers, hospitals and clinics, fire stations, and police stations), critical infrastructure (wastewater and water treatment plants, pump stations, storm and sanitary sewer lines, water distribution lines), and natural systems (parks and wetlands). The Climate Vulnerability Assessment also included vulnerable populations, as determined by key indicators such as the Healthy Places Index and the Climate Change and Health Vulnerability Indicators (CCHVI) developed by the State of California.
Present Situation
To obtain these preliminary results and assess the vulnerability of physical and natural assets in the City of Stockton, the technical team conducted a geospatial overlay analysis against a suite of climate hazard indicators to identify assets projected to be exposed to the hazards. Exposure scores were assigned to each asset for each climate hazard. Separately, each asset type was assigned a sensitivity score for each hazard, which describes the degree to which an asset or population is expected to be damaged or disrupted after exposure to a hazard, based on its material properties and other characteristics. Assets that are highly sensitive to a hazard are more likely to be damaged after exposure to that hazard, and assets with low sensitivity to a hazard are less likely to be damaged after exposure. Vulnerability is determined as a function of exposure and sensitivity, with the resulting vulnerability scores categorized as high, moderate, or low, to enable the technical team to identify the assets with the highest vulnerabilities.
The technical consultant will provide a presentation showing examples from the assessment of vulnerability for schools, community centers, roads, and water treatment plants. Heat and flooding are particularly key sources of vulnerabilities for schools, community centers, and other buildings.
FINANCIAL SUMMARY
This is informational only and will have no direct financial impact on the City Departments.