Category: Risk Analysis

Our new paper on perceptions of sea level rise in Climatic Change

10/10/2020

Our new paper on perceptions of sea level rise has been published in Climatic Change (Impact factor: 4.743). Below please find the abstract:
"Sea level rise (SLR) in the 21st century poses fundamental risks to coastal residents. The U.S. Gulf of Mexico Coast (Gulf Coast) is among the regions experiencing the most rapid relative SLR. Beyond its increasing exposure to SLR and related coastal flooding, the Gulf Coast is home to a large population and displays high social vulnerability. How the coastal population in this vulnerable region perceives the impending risks posed by SLR warrants further examination. Do coastal residents’ perceptions of SLR conform to the scientific projections? We adopt an integrative approach based on a 2019 survey merged with contextual data including percentage of population living within the Special Flood Hazard Area (SFHA) and social vulnerability at the county level, both of which are extracted from the Centers for Disease Control and Prevention. We find that public risk perceptions of sea level change are influenced by political predisposition, with Republicans being less likely than Democrats to expect SLR in the future. Moreover, SLR remains temporally distant issue among coastal residents. We then directly compare public expectations and scientific estimations of SLR in five states of the U.S. Gulf Coast region and find that coastal residents in states that have experienced faster SLR in the past are more optimistic about future SLR by underestimating its magnitude compared to those experiencing slower SLR. Moreover, we find that people likely conflate the severity with likelihood of SLR risk. The contextual force represented by percentage of population living within the SFHA designated by the Federal Emergency Management Agency (FEMA) can significantly influence individuals’ estimations of future SLR, with higher percentages leading to higher estimates. We suspect that the SFHA has become a powerful risk communication tool that influences coastal residents’ judgments about future risk.

Figure 3. Comparison of public estimation with scientific estimation of SLR at five locations in Texas, Louisiana, Mississippi and Alabama, Florida Panhandle, and Florida Peninsula along the U.S. Gulf Coast. Percentages assigned at lower level and upper level in each figures represent percentages of respondents who estimated future SLR to be lower than the 5th and higher than the 95th scientific estimates, respectively (Source: Shao et al. in press).

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Our new paper on risk perceptions of COVID-19

7/17/2020

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In a new paper that has been published in Social Science & Medicine (Impact Factor: 4.634), we studied the factors on risk perceptions of COVID-19. Below please find the abstract:

Rationale
COVID-19 poses an unprecedented level of risks to the public health and well-being in the United States. This pandemic has led to cascading effects such as rapidly rising unemployment rate, deteriorating mental health, and disturbed stock market among others. This disease presents an opportunity for social scientists to conduct a timely study of American public perceptions of risks associated with COVID-19.

Objective
Due to a great amount of uncertainties surrounding this disease, the public has to rely upon authorities for information and guidance. In this study, we aim to answer this overarching question: how does confidence in political leaders shape American public risk perceptions of COVID-19?

Method
Based on a nationally representative data conducted in March 2020, we use latent mean comparison analysis and Structural Equation Modelling to make several findings.

Results
First, confidence in political leaders can reduce risk perceptions of this disease. Second, conservatives show lower risk perceptions than liberals and moderates. Third, confidence in political leaders has mediating effects among conservatives and white Americans, where conservatives and white Americans who have more confidence in political leaders show lower risk perceptions of COVID-19 than other conservatives and white Americans who have less confidence.

Conclusion
These results highlight the enormous challenges facing policy makers who intend to design and implement national public health policies in this polarized environment.

Figure 1. Structural Equation Modelling Diagram (Shao and Hao, 2020 b)

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A new paper in Scientific Reports

12/29/2019

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In a new paper, we assessed the socio-economic vulnerability to flash floods across the contiguous U.S. This paper has been published in Scientific Reports (a Nature journal). For more information, below please find the abstract:

"Flash flood is among the most catastrophic natural hazards which causes disruption in the environment and societies. Flash flood is mainly initiated by intense rainfall, and due to its rapid onset (within six hours of rainfall), taking action for effective response is challenging. Building resilience to flash floods require understanding of the socio-economic characteristics of the societies and their vulnerability to these extreme events. This study provides a comprehensive assessment of socio-economic vulnerability to flash floods and investigates the main characteristics of flash flood hazard, i.e. frequency, duration, severity, and magnitude. A socio-economic vulnerability index is developed at the county level across the Contiguous United States (CONUS). For this purpose, an ensemble of social and economic variables from the US Census and the Bureau of Economic Analysis were analyzed. Then, the coincidence of socio-economic vulnerability and flash flood hazard were investigated to identify the critical and non-critical regions. Results show that the southwest U.S. experienced severe flash flooding with high magnitude, whereas the Northern Great Plains experience lower severity and frequency. Critical counties (high-vulnerable-hotspot) are mostly located in the southern and southwestern parts of the U.S. The majority of counties in the Northern Great Plains indicate a non-critical status."

Figure 7. Flash flood hazard characteristics converted from gauge station to the county-scale (Khajehei et al. 2020)

Figure 8. Maps of the counties where flashflood extremes coincide with socio-economic vulnerability extremes (Khajehei et al. 2020)

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A new paper in Palgrave Communications

8/20/2019

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In a new paper, we used Google Trends to reveal the spatiotemporal patterns of US drought awareness. This paper has been published in Palgrave Communications (a Nature journal, now Humanities and Social Sciences Communications). Here is more information about this paper:

Article Title: Spatiotemporal Patterns of US Drought Awareness

Summary:
Drought is a creeping climatological phenomenon with persistent precipitation deficits. The intangible and gradual characteristics of drought cause a lack of social response during the onset. The level of awareness of a local drought increases rapidly through mass media reports and online information searching activities when the drought reaches its peak severity. This high level of local drought awareness drives concerns for water shortage and support for water policy. However, spatiotemporal patterns of national-scale drought awareness have never been studied due to constraints imposed by time-consuming and costly survey data collection and surveys' limited sample sizes.
Here, we present the national-scale study to reveal the spatiotemporal patterns of drought awareness over the contiguous United States (CONUS) using Google Trends data and an advanced statistical technique, Principal Component Analysis (PCA). Results show that the first two PC modes can explain 48% (38% for PC1 and 10% for PC2; see Figures below) of the total variance of state-level drought awareness. We find that the PC1 mode relates to a national pattern of drought awareness across the CONUS. The spatiotemporal patterns further imply that residents in the Northeastern US region are the most aware of the emergence of drought, regardless of the geographic location of the occurrence. The results illustrate how search engine queries and social media data can help develop an effective and efficient plan for drought mitigation in the future.

The following Figure comes from Kim et al. (2019):

Figure 1: Major principle components of state-level drought awareness and state-level drought risk over the contiguous United States. Temporal correlations of Drought Awareness from the first two major modes with individual state-level drought awareness ((c) and (d), respectively) and individual state-level drought risk ((e) and (f), respectively). White colored states depict the states with insignificant temporal correlation at the 99% confident level.

Figure 2: State-level correlation analysis of drought awareness and drought risk. Colors in the grid cells depict temporal correlation coefficients of state-level drought awareness (left triangle) and state-level drought risk (right triangle) of one state with those of the rest 48 states. To assist interpretation, areas that depict interstate relationships within the region (green colored boundaries) and across regions (blue colored boundaries) are shown in the legend box at upper-left corner.

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A new paper in Disasters

6/28/2019

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Our new paper was published in Disasters (impact factor: 1.797). Here is the abstract:

"It is of significance to assess and depict community vulnerability to floods and hurricanes. Over the past several decades, flooding and hurricanes have affected millions of people and caused massive economic losses. Despite efforts to reduce risks, these natural hazards remain to be a considerable challenge to coastal communities. In this paper, Geographic Information Systems (GIS) methods are used to analyze coastal communities’ vulnerability to hurricanes and flooding along the U.S. Gulf coast, which is prone to these two hazards. Specifically, two types of quantitative indicators are developed: exposure to hurricanes and flooding, based on data from multiple sources such as National Climate Data Center and National Flood Insurance Program among others, and a social vulnerability index, constructed on census data at census tract level. These indices are combined to depict the spatial patterns of overall community vulnerability to flooding and hurricane hazards along the U.S. Gulf Coast. Results of this study can potentially inform disaster management agencies, county governments and municipalities of areas with heightened community vulnerabilities. The demonstration of geographic distribution of community vulnerability can assist decision makers in prioritizing to‐do items and designing policies/plans for more effective allocation of resources. We end this paper by discussing the limitations to the present study and the practical implications of the assessment."

The following two figures are from this article (Shao et al. forthcoming).

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Our new paper on flood perceptions

12/21/2018

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Our new paper on how physical geography influences perceptions of flooding just got published online in the Journal of Hydrology (impact factor: 4.405). Here is the abstract of this paper:

"How does physical history of flood-related hazards affect individuals’ perceptions? The present study represents a unique effort to understand perceptions of flood hazards in light of the geographic background. Situated in Alabama, the United States, the cities of Mobile and Huntsville display two different physical geographic contexts. Despite one being a coastal city (Mobile) and the other being an inland city, both are similarly vulnerable to flooding. We first present results of historical analyses of heavy precipitation in both cities and analysis of storm surge history in the city of Mobile. We then report results of both descriptive statistical and inferential statistical analyses based on a two-city residents’ survey that was conducted in the spring of 2016. We find that residents in both cities are able to connect the particular natural hazard of flooding with their physical environments. Residents in both cities are influenced by their perceptions of precipitation when making assessments of flooding. Despite the fact that Huntsville has not experienced heavy precipitation events as much as Mobile in recent history, residents of Huntsville tend to link heavy rainfall – the most frequent cause of flooding in that city, with flooding. In contrast, residents of Mobile tend to link hurricanes, more particularly hurricane number, with flooding. These results show that people are attuned to their physical environments and take into consideration their personal observations when forming perceptions of natural hazards. More studies need to be conducted to further investigate the dynamics of physical exposure to hazards and risk perceptions in other geographic areas."

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Some criticism about using climate-economics models to guide climate policies

10/8/2018

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William Nordhaus was awarded the Nobel Prize in Economic Sciences because of his decades' effort to integrate climate sciences into economic models. His Dynamic Integrated Climate and Economy (DICE) is used to explain how Greenhouse Gases emissions if not tamed could lead to catastrophes down the road. This pioneering effort is not immune to criticism. Using climate-economy integrated models to design and implement specific climate policies is subject to misuses, as Robert Pindyck contended. According to Pindyck, modeler's limited knowledge about climate sensitivity and arbitrary selection of functional forms and parameter values do not make results from complicated models more valid than modeler's own "expert" opinion.

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Visit at Princeton

6/21/2018

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I enjoyed the visit at the Department of Civil and Environmental Engineering at Princeton University. I have had great discussions with Professor Lin and her Hurricane Hazards and Risk Analysis Research Group.

Princeton Campus

I am sitting on a chair on Princeton Campus

I am standing in front of the student center

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A seminar talk at Princeton University

6/14/2018

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I am honored to be invited to give a seminar talk, entitled "Understanding Human Judgement on Environmental Risks and Hazards in a Geographic Context," at the Department of Civil and Environmental Engineering at Princeton University on June 21.

The abstract of the talk is as follows:
"The coupling effects of changing climate and rising concentration of population and assets in the coastal regions have increased the threat of potential damages. There is an urgent need for coastal communities to prepare well for future hazards through mitigation and adaptation measures. A growing number of empirical studies have found that peoples’ motivation of voluntary risk mitigation and adaptation is low unless actual risk can be perceived. Risk perception is thus the precondition for adaptive behavior. It is of both intellectual and practical interests to study what affects individuals’/communities’ risk perceptions. In this talk, I will present four of my previous studies. The first three studies are focused on the individual level and the fourth on the aggregate level. I will start with understanding how local weather and climate affect American public risk perceptions of climate change. I will then discuss how the spatial context represented by past flooding events and estimated flooding risks influence costal residents’ voluntary flood insurance purchase decisions and their support for flood adaptation policies. As many policies are designed and implemented at an aggregate level (i.e., state, county, city), it is necessary to examine aggregate-level risk perceptions. In the fourth study, I will focus on how the contextual hurricane risks in conjunction with community resilience shape county-level perceptions of hurricane-related risks. I will end with a research agenda linking communities’ perception with contextual risks and community resilience. I contend that the cognitive dimension including both risk perceptions and perceived adaptive capacity is not represented in any of the existing community resilience indexes, and therefore needs to be measured, quantified, and incorporated into a more comprehensive index."

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