Sociodemographic factors and vulnerability to multiple extreme weather events: A national study in the U.S

Abstract

Background: Millions of U.S. residents experience increasingly more prevalent weather events due to climate change, however, there is limited research exploring the vulnerability to multiple extreme weather events using a national U.S.

Aims: Identify patterns in exposures to climate events, and examine sociodemographic factors associated with increased climate event vulnerability.

Method: Data was retrieved from the May 2022 American Trends Panel, a nationally representative sample of 10,282 United States adults. We performed a latent class analysis, a statistical method used to identify unobserved subgroups (latent classes) within a population, to group respondents by patterns in five climate event experiences (heatwave, intense storm, wildfire, drought, and sea level rise), and analyzed variables associated with vulnerability to climate events using weighted multinomial logistic regression, a statistical method that models the probability of membership in one of several outcome categories (climate vulnerability groups) relative to a reference category, while accounting for survey weights to ensure generalizability to the U.S.

Results: Respondents were categorized into four latent classes, which are unobserved subgroups identified through patterns in exposures to five climate events (heatwave, intense storm, wildfire, drought, and sea level rise). These subgroups were based on exposures to heatwave (42.5 %), intense storm (43.2 %), wildfire (21.3 %), drought (30.8 %) and sea level rise (15.8 %): high (9.8 %), heat-storm (22.2 %), heat-drought (13.4 %), and low (54.6 %) climate event vulnerability. Relative risk for high climate event vulnerability refers to the likelihood of belonging to the "high vulnerability" group compared to the "low vulnerability" group. It is assessed using the relative risk ratio (RRR), which is a measure of the association between a particular sociodemographic factor (e.g., age, gender, region) and the likelihood of being in a specific vulnerability group relative to the reference group. For instance, an RRR <1 indicates a reduced risk, while an RRR >1 indicates an increased risk compared to the reference category. Relative risk for high climate event vulnerability was lower for older adults (RRR = 0.39, p < 0.001), potentially reflecting a greater capacity to cope with certain climate events, such as access to stable housing or resources. However, this finding should not be interpreted as older adults being universally less vulnerable. Numerous studies have shown that older adults are at significantly higher risk during heatwaves due to physiological and social factors, which our analysis may not fully capture. Relative risk for high vulnerability was higher for females (RRR = 1.42, p = 0.01) and residents in the South (RRR = 2.05, p = 0.003) and West (RRR = 9.31, p < 0.001) geographic regions. Relative risk for heat-drought was higher for Hispanic adults (RRR = 1.51, p = 0.03), but lower for high school graduates (RRR = 0.40, p = 0.01) compared to those who did not complete high school.

Conclusions: We identified several underlying climate event exposure subpopulations, ranging from low to high vulnerability. As climate-related events become more frequent, our results provide critical insights for stakeholders to identify high-risk individuals and prioritize resources for disaster management.

Keywords: Climate change; Extreme weather; Flood; Heat; Latent class analysis; Storm; Wildfire.