Sammy Zahran

Personal efficacy, the information environment, and attitudes toward global warming and climate change in the United States.

Despite the growing scientific consensus about the risks of global warming and climate change, the mass media frequently portray the subject as one of great scientific controversy and debate. And yet previous studies of the mass publics subjective assessments of the risks of global warming and climate change have not sufficiently examined public informedness, public confidence in climate scientists, and the role of personal efficacy in affecting global warming outcomes. By examining the results of a survey on an original and representative sample of Americans, we find that these three forces-informedness, confidence in scientists, and personal efficacy-are related in interesting and unexpected ways, and exert significant influence on risk assessments of global warming and climate change. In particular, more informed respondents both feel less personally responsible for global warming, and also show less concern for global warming. We also find that confidence in scientists has unexpected effects: respondents with high confidence in scientists feel less responsible for global warming, and also show less concern for global warming. These results have substantial implications for the interaction between scientists and the public in general, and for the public discussion of global warming and climate change in particular.

Vulnerability and Capacity: Explaining Local Commitment to Climate-Change Policy

We examine the reasons why a US locality would voluntarily commit to the Cities for Climate Protection (CCP) campaign. Using geographic information systems analytic techniques, we map and measure a localitys vulnerability to climate-change impacts at the county level of spatial precision. We analyze multiple measures of climate-change vulnerability, including expected temperature change, extreme weather events, and coastal proximity, as well as economic variables, demographic variables, and civic-participation variables that constitute a localitys socioeconomic capacity to commit to costly climate-change policy initiatives. Bivariate and logistic regression results indicate that CCP-committed localities are quantitatively different to noncommitted localities on both climate-change risk and socioeconomic-capacity dimensions. On vulnerability measures, the odds of CCP-campaign participation increase significantly with the number of people killed and injured by extreme weather events, projected temperature change, and coastal proximity. On socioeconomic-capacity measures, the odds of CCP-campaign involvement increase with the percentage of citizens that vote Democrat and recycle, as well as the number of nonprofit organizations with an environment focus. The odds decrease in a county area as the percentage of the labor force employed in carbon-intensive industries increases.

Risk, Stress, and Capacity: Explaining Metropolitan Commitment to Climate Protection

Climate change and mitigation policies adopted by a locality indelibly impact urban form, landscape, and economy. The Cities for Climate Protection (CCP) has become a dominant movement organizing the localities to proactively address climate change. This study examines metropolitan area commitment to the CCP. Geographic information systems (GIS) and statistical techniques are used to analyze metros on dimensions of climate change risk, stress, and civic capacity. “Climate change risk” measures a metro areas coastal proximity, ecosystem sensitivity, and susceptibility to extreme weather events. “Climate change stress” summarizes transportation, energy, and production practices that adversely affect climate systems. “Civic capacity” estimates human capital and environmental concern variables that constitute a metro areas ability to commit to policy initiatives. Statistical results indicate that high stressor areas are significantly less likely to participate in the CCP campaign, and metros high in civic capacity are significantly more likely to commit to the CCP campaign.

Social vulnerability and the natural and built environment: a model of flood casualties in Texas

Studies on the impacts of hurricanes, tropical storms, and tornados indicate that poor communities of colour suffer disproportionately in human death and injury.(2) Few quantitative studies have been conducted on the degree to which flood events affect socially vulnerable populations. We address this research void by analysing 832 countywide flood events in Texas from 1997-2001. Specifically, we examine whether geographic localities characterised by high percentages of socially vulnerable populations experience significantly more casualties due to flood events, adjusting for characteristics of the natural and built environment. Zero-inflated negative binomial regression models indicate that the odds of a flood casualty increase with the level of precipitation on the day of a flood event, flood duration, property damage caused by the flood, population density, and the presence of socially vulnerable populations. Odds decrease with the number of dams, the level of precipitation on the day before a recorded flood event, and the extent to which localities have enacted flood mitigation strategies. The study concludes with comments on hazard-resilient communities and protection of casualty-prone populations.

Linking source and effect: resuspended soil lead, air lead, and children's blood lead levels in Detroit, Michigan.

This study evaluates atmospheric concentrations of soil and Pb aerosols, and blood lead levels (BLLs) in 367839 children (ages 0-10) in Detroit, Michigan from 2001 to 2009 to test a hypothesized soil → air dust → child pathway of contemporary Pb risk. Atmospheric soil and Pb show near-identical seasonal properties that match seasonal variation in childrens BLLs. Resuspended soil appears to be a significant underlying source of atmospheric Pb. A 1% increase in the amount of resuspended soil results in a 0.39% increase in the concentration of Pb in the atmosphere (95% CI, 0.28 to 0.50%). In turn, atmospheric Pb significantly explains age-dependent variation in child BLLs. Other things held equal, a change of 0.0069 μg/m(3) in atmospheric Pb increases BLL of a child 1 year of age by 10%, while approximately 3 times the concentration of Pb in air (0.023 μg/m(3)) is required to induce the same increase in BLL of a child 7 years of age. Similarly, a 0.0069 μg/m(3) change in air Pb increases the odds of a child <1 year of age having a BLL ≥ 5 μg/dL by a multiplicative factor of 1.32 (95% CI, 1.26 to 1.37). Overall, the resuspension of Pb contaminated soil explains observed seasonal variation in child BLLs.

Collective Action, Environmental Activism, and Air Quality Policy

This article attempts to respond to Ostrom’s call for a behavioral model of collective action by generalizing the collective interest model of mass political action to explain citizen policy support and personal behavioral intentions in the context of air quality policy. The collective action problems inherent in air quality policy provide a critical research setting for testing hypotheses of the collective interest model. Key elements of the collective interest model—perceived risk, trust in policy elites, knowledge of the policy problem, and efficacy—are found to be directly, and positively, related to support of government policies and intentions to engage in personal behaviors that might improve air quality. The article discusses the implications for using the collective interest model as general behavioral theory of collective action.

The Rising Costs of Floods: Examining the Impact of Planning and Development Decisions on Property Damage in Florida

Abstract The rising economic cost of floods in the United States cannot be explained solely by monetary inflation or growth in coastal populations. Damaging flood events are also influenced by the way society plans for and physically develops its communities, influencing where structures and impervious surfaces are concentrated and how hydrological systems are altered. We analyze 383 nonhurricane flood events in Florida counties between 1997 and 2001 to isolate how planning decisions and their effects on the built environment affect property damage caused by floods. Our results suggest that alteration of naturally occurring wetlands significantly increases the property damage caused by floods, all else equal. Also, nonstructural methods such as the Federal Emergency Management Agencys Community Rating System, while providing inexpensive means of reducing property damage directly, may also indirectly encourage more development in hazardous areas.

Identifying the impact of the built environment on flood damage in Texas

Floods continue to pose the greatest threat to the property and safety of human communities among all natural hazards in the United States. This study examines the relationship between the built environment and flood impacts in Texas, which consistently sustains the most damage from flooding of any other state in the country. Specifically, we calculate property damage resulting from 423 flood events between 1997 and 2001 at the county level. We identify the effect of several built environment measures, including wetland alteration, impervious surface, and dams on reported property damage while controlling for biophysical and socio-economic characteristics. Statistical results suggest that naturally occurring wetlands play a particularly important role in mitigating flood damage. These findings provide guidance to planners and flood managers on how to alleviate most effectively the costly impacts of foods at the community level.

The urban rise and fall of air lead (Pb) and the latent surge and retreat of societal violence

We evaluate air Pb emissions and latent aggravated assault behavior at the scale of the city. We accomplish this by regressing annual Federal Bureau of Investigation aggravated assault rate records against the rise and fall of annual vehicle Pb emissions in Chicago (Illinois), Indianapolis (Indiana), Minneapolis (Minnesota), San Diego (California), Atlanta (Georgia), and New Orleans (Louisiana). Other things held equal, a 1% increase in tonnages of air Pb released 22 years prior raises the present period aggravated assault rate by 0.46% (95% CI, 0.28 to 0.64). Overall our model explains 90% of the variation in aggravated assault across the cities examined. In the case of New Orleans, 85% of temporal variation in the aggravated assault rate is explained by the annual rise and fall of air Pb (total=10,179 metric tons) released on the population of New Orleans 22 years earlier. For every metric ton of Pb released 22 years prior, a latent increase of 1.59 (95% CI, 1.36 to 1.83, p<0.001) aggravated assaults per 100,000 were reported. Vehicles consuming fuel containing Pb additives contributed much larger quantities of Pb dust than generally recognized. Our findings along with others predict that prevention of childrens lead exposure from lead dust now will realize numerous societal benefits two decades into the future, including lower rates of aggravated assault.

Children's blood lead and standardized test performance response as indicators of neurotoxicity in metropolitan New Orleans elementary schools

This study analyzes pre-Katrina variation in aggregate student performance and childrens blood lead (BPb) in 117 elementary school districts in metropolitan New Orleans. Fourth grade student achievement on Louisiana Educational Assessment Program (LEAP) tests were analyzed as a function of BPb for children 1-6 years old within school districts, controlling for student-teacher ratios, percent of students eligible for a free or discounted lunch, and school racial demography. Measures of performance across subject areas (English Language Arts, Science, Mathematics, and Social Studies) include school Achievement Test Scores (ATS) and indices of agreement and variation in student achievement. ATS are measured on a 5-point scale, corresponding to achievement categories of advanced=5 to unsatisfactory=1. Regression results show that median BPb (microg/dL) and percent of children with BPb > or =10 microg/dL are significantly associated with reductions in test scores across all subjects and depress variation in student performance across achievement categories. These data suggest that assisting children with improved school performance requires alleviation of pre-school Pb exposure and its associated neurotoxic damage. Cost-benefit calculations suggest that it is more cost effective to pay for onetime primary prevention instead of paying continuous expenses focused on reversing neurotoxic damage.