Abstract A variety of indices have been used to determine physiological risk imposed by extreme heat, humidity, and other variables. Given the breadth of such indices and their potential uses, it is important to assess correlations between these indices and human experiences and responses to heat conditions. This paper compares the widely recognized Heat Index; the newly developed Heat Risk tool, now used experimentally by the National Weather Service; and human perceptions of dangerous heat conditions in central South Carolina, assessed through perceived comfort. Data and forecasts from two consecutive summers suggest that the categories used in the new Heat Risk tool may underestimate heat risk on several summer days compared to the risk measured by the Heat Index and as reflected in perceived comfort among vulnerable populations exposed to heat stress.

Growing concern over the impacts of extreme heat has led to increased attention on enhancing the effectiveness of public health interventions. This paper addresses the intersecting challenges of reaching vulnerable populations in distinct geographic contexts and understanding their beliefs and attitudes about heat risk. Specifically, it reports how social and behavioral approaches can inform public health interventions for vulnerable groups using an expanded theory of planned behavior (TPB). The standard components of the TPB, which include an individual's attitude toward taking protective measures, subjective social norms regarding the risk, and perceived behavioral control in mitigating that risk, are supplemented with additional constructs relevant to heat risk communication. These include perceived severity and susceptibility to heat impacts, adaptation behaviors, and the perceived value and comprehension of heat warning information. A cross-sectional study (N 5 273) was administered across four locations in the central Midlands region of South Carolina, United States, to include different vulnerable populations, including low-income individuals, African Americans, the unhoused, and Spanish speakers in both urban and rural settings. Hierarchical regression and moderation analyses demonstrate that the predictive power of TPB variables and the strength of specific constructs and relationships within the model, particularly perceived behavioral control, vary significantly across geographic locations. These findings highlight the contextual nature of behavioral intentions and the influence of geographic, community-specific, socioeconomic, social, and structural factors, including variations in physical heat exposure and access to support structures, in shaping those intentions. In addition, the study introduces an exploratory, place-based framework to aid interpretation of how vulnerability and access to community support help explain observed differences in the significance of TPB constructs across sites.

An actor-centred, risk-based framework for analysing limits to the capacity to adapt to climate change impacts, developed in the context of IPCC AR5 (Dow et al,. 2013b), was refined in the IPCC AR6 reports (Mechler et al., 2020; O 'Neill et al., 2022; Thomas et al., 2021). In this paper, we centre the analysis on how institutional contexts shape and influence adaptation limits as experienced by social actors. We emphasise institutions ' stability over time leading to delayed adaptation, their role in protecting more powerful rather than weaker social interests, and their tendency to generate punctuated rather than smooth changes in vulnerability to climate risks. We illustrate these arguments with two case studies of socio-ecological institutional regimes facing adaptation limits: water resources management in the Colorado River Basin; and disaster risk management in The Bahamas. These represent divergent risk governance contexts generating limits to adaptation for multiple social actors, despite the availability of plausible adaptation pathways. Our aim is to contribute to a generalisable approach to adaptation limits which can be applied in identifying and assessing critical choices in responses to growing climate change impacts.

The escalating awareness of heat-related risks and the associated imperative to enhance preparedness strategies at various levels has spurred a growing emphasis on disseminating knowledge about heat vulnerability. These efforts aim to equip diverse stakeholders with practical heat planning and forecasting tools. The success of these communication initiatives hinges on understanding the nuanced perceptions of risk and the priority assigned to addressing heat as a health risk. This paper delves explicitly into the unhoused population’s risk perceptions and coping strategies. Acknowledged as one of the most underserved and vulnerable groups to extreme heat, unhoused individuals face prolonged exposure, a heightened frequency of mental and physical health issues, and limited coping resources during extreme heat events. Despite widespread acknowledgment of their vulnerability, little attention has been directed towards researching health behavior within this demographic about excessive heat. We developed a survey instrument using the theory of planned behavior (TPB) to bridge this gap. We collected quantitative survey data from unhoused populations in Columbia, South Carolina, an area of the United States that experiences extreme heat events and has a sizeable unhoused population. Using a series of hierarchical multiple regression models, our findings indicate that TPB variables predict the intention to avoid the heat while considering additional coping strategies common among unhoused individuals. These findings offer valuable insights for public health researchers, practitioners, and community officials engaged in direct interactions with unhoused populations, informing how this underserved group manages excessive heat exposure.

Over 5 years, multiple hurricanes and a pandemic impacted small businesses in Charleston, South Carolina. In order to better understand the impacts of disasters on public-facing small businesses, we conducted a case study of customer, labor, location, and supply chain mobility. Although the disaster contexts of multiple hurricanes and the 2019 novel coronavirus (COVID-19) pandemic vary considerably, comparing the experiences of small business operators furthers our understanding of local disruptions and the potential for adaptive capacity. Drawing on 2 years of survey data, we focus on the importance of mobility to public-facing (e.g. service and recreation) small business recovery and adaptation. We then consider the relationship between multiple forms of mobility and resilience to two different disaster types. We conclude by identifying additional areas of small business adaptation and resilience inquiry informed by both hurricane and pandemic experiences. In contrast to previous global or regional mobility studies, this case study explores hyper-local small business mobility disruptions.

The IPCC's Sixth Assessment Report Working Group II report of (2022) has brought greater attention to the issue of limits to the capacity to adapt to climate change. But the report also showed that research in the field continues to be fragmented and under‐developed, and that the problem of limits is not widely considered in policy. In this paper, we argue for a more coherent, interdisciplinary approach to research on adaptation limits, linked to the concept of transformative adaptation. A risk‐based approach to adaptation limits offers a framework to deepen, broaden and connect research which responds to the needs of policymakers. We set out four promising directions for future research on: the dimensions of limits; the dynamics of limits; formalization of research on limits; and ethics and justice challenges underpinning adaptation limits.

With the increase in severity and frequency of natural hazards due to climate change, developing a holistic understanding of community resilience factors is critically important to disaster response and community support. Our investigation of small business survey responses about COVID-19 impacts finds that they are conduits of national support to their local communities. Small businesses that have demonstrated high levels of pre-disaster local involvement are more likely to take an active role in community resilience during a disaster, regardless of their own financial security. In addition, businesses with natural hazard experience before or during COVID-19 provided help to more community groups than hazard inexperienced businesses. While community resilience models often characterize small businesses as passive actors using variables such as employment or financial security, this research suggests that small businesses take an active role in community resilience by providing critical local support. The pandemic presented an opportunity to consider small business’ role in community resilience nationally, which was utilized here to identify the multi-dimensional factors that predict small business operators’ community disaster support. This study improves upon previous research by studying the small business-community resilience interface at both regional (n = 184) and national (n = 6,121) scales. We predict small business’ active involvement in community resilience using random forest machine learning, and find that adding social capital predictors greatly increases model performance (F1 score of 0.88, Matthews Correlation Coefficient of 0.67).

Background Projected trajectories of climate and land use change over the remainder of the twenty-first century may result in conditions and situations that require flexible approaches to conservation planning and practices. For example, prescribed burning is a widely used management tool for promoting longer-term resilience and sustainability in longleaf pine ecosystems of the southeastern United States, but regional stressors such as climatic warming, changing fire conditions, and an expanding wildland-urban interface may challenge its application. To facilitate the development of fire management strategies that account for such changes, we surveyed nearly 300 fire managers to elicit information on the criteria used for prioritizing burn sites, current burning practices and constraints, and expectations for changes in burning opportunities, including those pertaining to climate change and urban growth. Results Respondents noted that their most common criteria for selecting longleaf pine stands for burning were fire history, ecosystem health, and fuel reduction, with the presence of threatened and endangered species also given priority by public land managers. Many respondents (38%) cited recent burn frequencies that fall short of historic burn intervals. Barriers to burning included legal, institutional, and managerial constraints, such as proximity to human developments, public concerns, and risk aversion, as well as environmental and resource constraints, including weather, air quality restrictions, and lack of personnel, equipment, or funding. Roughly half of all respondents expect that opportunities to burn will be reduced over the next 30 years, particularly during the growing season. Fire manager perceptions of factors that will limit prescribed burning in the future include a similar suite of constraints, many of which will be affected by projected regional changes in land use and climate. Conclusions On an organizational level, burn window availability and resource limitations constrain prescribed burning practices. More broadly, policy and legal frameworks coupled with trends in urbanization and climate change are expected to interact with operational constraints to challenge managers' abilities to implement landscape-scale burning strategies and achieve restoration goals. Additional research and engagement with fire managers are needed to investigate opportunities for introducing policy flexibility, leveraging shared management interests, and developing creative solutions to expand burning opportunities.

After centuries of adapting to coastal living, increases in stormwater and tidal flooding events, along with projected sea level rise, led Charleston, South Carolina, USA to define flooding as an existential threat to the city. With billions of planned flood management projects underway, and additional billions of federal disaster flood recovery funds allocated to the State of South Carolina, the Governor's office established a South Carolina Office of Resilience in September 2020, with a focus on water management. The City of Charleston developed its own Flooding and Sea Level Rise Strategy. Simultaneously, the fourth National Climate Assessment pointed to heat health risks and projected costs of lost labor productivity concentrated in the Southeast, yet local recognition of heat as an equivalent threat to flooding was not apparent. Although Charleston's All Hazards Vulnerability Assessment included extreme heat as a significant hazard, without a group focused on heat, ongoing work in the city continued to prioritize water management as annual flood events rapidly escalated. This narrow adaptation framing was further solidified as funding focused on flood recovery and adaptation and technical experts worked within water-related boundaries. These interacting forces led to Hazard Bias, an inherent organizational process of reinforcing focus on a single hazard in the context of compound, complex hazard risks. To adapt to increasing heat, Charleston will need to raise compound risk awareness and adjust its capital investments in resilience to be inclusive of heat mitigation and adaptation as well as water. Yet in 2020 Charleston lacked basic urban heat data, technical expertise, and a strong source of motivation to develop a prioritization approach for recognizing multiple risks and complementary adaptation opportunities in those investments. Recognizing the inherent bias, a new coalition of heat researchers, practitioners, and health experts launched a tripartite heat-health research program and spurred the development of a new heat network in Charleston. The network reduced hazard bias by raising heat-health risk awareness and by intervening in adaptation planning to broaden water-only considerations to be inclusive of water AND heat. This paper provides a detailed case study how the intersections of multiple networks, messengers, and messages contributed to broadening the local resilience agenda from a “hazard bias” and how the lessons learned during this transformative process further reveal health inequities.

Small business operators are increasingly faced with difficult decisions in the face of complex and often uncertain disasters aggravated by climate change. In coastal regions of the SE USA, the COVID-19 pandemic and a recent history of hurricanes provided an opportunity to study the relationships between the three components of the theory of planned behavior (TPB) -- operator's attitudes, subjective social norms, and perceived behavioral control -- and their actualized behaviors in relation to hurricane preparation and COVID-19 response. In a study of 168 small business operators, we find that previously experienced and anticipated event (hurricane) components are reliable measures of both taking protective action for hurricanes (AUC = 0:74) and for the COVID-19 pandemic (MCC = 0:87) in binary logistic regression models. This study advances the fields of disaster resilience planning and behavioral economics by extending the TPB from intended to actualized disaster-related behaviors. We demonstrate that with positive attitudes towards preparation for anticipated events, small businesses are predisposed to take protective actions to respond to unanticipated events. As climate change is likely to increase complex disasters, understanding the components of small business operators' actualized preparedness behaviors highlights an avenue for supporting both business and community resilience.

Recent studies have characterized individually experienced temperatures or individually experienced heat indices, including new exposure metrics that capture dimensions of exposure intensity, frequency, and duration. Yet, few studies have examined the personal thermal exposure in underrepresented groups, like outdoor workers, and even fewer have assessed corresponding changes in physiologic heat strain. The objective of this paper is to examine a cohort of occupationally exposed grounds and public safety workers (n = 25) to characterize their heat exposure and resulting heat strain. In addition, a secondary aim of this work is to compare individually heat index exposure (IHIE) across exposure metrics, fixed-site in situ weather stations, and raster-derived urban heat island (UHI) measurements in Charleston, SC, a humid coastal climate in the Southeastern USA. A Bland–Altman (BA) analysis was used to assess the level of agreement between the personal IHIE measurements and weather-station heat index (HI) and Urban Heat Island (UHI) measurements. Linear mixed-effect models were used to determine the association between individual risk factors and in situ weather station measurements significantly associated with IHIE measurements. Multivariable stepwise Cox proportional hazard modeling was used to identify the individual and workplace factors associated with time to heat strain in workers. We also examined the non-linear association between heat strain and exposure metrics using generalized additive models. We found significant heterogeneity in IHIE measurements across participants. We observed that time to heat strain was positively associated with a higher IHIE, older age, being male, and among Caucasian workers. Important nonlinear associations between heat strain occurrence and the intensity, frequency, and duration of personal heat metrics were observed. Lastly, our analysis found that IHIE measures were significantly similar for weather station HI, although differences were more pronounced for temperature and relative humidity measurements. Conversely, our IHIE findings were much lower than raster-derived UHI measurements. Real-time monitoring can offer important insights about unfolding temperature-health trends and emerging behaviors during thermal extreme events, which have significant potential to provide situational awareness.

Climate risks are motivating adaptation with local municipal actors becoming key participants in a complex web of climate risk communication. Some cities have created civil service positions focused on climate resilience. We conducted interviews with six such individuals in four U.S. Atlantic coast cities to investigate how they think about and negotiate communication challenges associated with implementation of climate resilience strategies. We grounded our study in the Social Amplification of Risk Framework (SARF), which despite its longevity and wide usage has rarely been used to understand the role of government actors. We found substantial complexity in how these government representatives develop both amplifying and attenuating communication strategies as they often simultaneously reach multiple audiences holding different perspectives. They are familiar with and employ risk communication practices. However, they report needing to modify their efforts as climate adaptation issues and goals evolve over time, and experiment in situations, such as discussions of retreat, where established communication practices provide insufficient guidance. In order to develop a deeper understanding of the governmental risk communication actors, we suggest four potential avenues for taking advantage of the strengths of SARF as a framework for connecting and integrating with other models and theories. We also propose several directions for research based on the challenges these practitioners are finding in their work to facilitate adaptation to climate risks. The activity of government actors is rich in its applied risk communication practice and its challenges offer new questions to expand our thinking about the SARF and risk communication more broadly.

In the US alone, there are over 200 tools that support climate adaptation planning, along with a large number of case studies documenting their use. Case studies frequently document positive results. Systematic assessment of processes can provide important benefits, including justification for action and expenditures, promotion of learning and adaptive management, accountability, and ensuring "fit" with other goals. There are very few such assessments in the context of climate adaptation planning, despite of the emphasis on the development and use of planning tools by federal and state agencies, university researchers, and non-profit organizations. We undertook an effort to assess the outcomes resulting from fourteen applications of the Vulnerability, Consequences, and Adaptation Planning Scenarios (VCAPS) process, which we helped develop and implement. VCAPS is designed to facilitate information exchange, co-production of knowledge, and stakeholder collaboration while helping communities appraise climate change-related risks and devise strategies to manage them. Using qualitative interviews we explored the perceived value and the measurable performance outcomes of VCAPS at both individual and community scales occurring 3-10 years after the processes were conducted, allowing participants to take a broader view of "success" and reflect on how different forms of success emerged over time. Although the assessment of each case is based on a small number of interviews, we learned that VCAPS informed plans and decisions of municipalities, informed actions and decisions of other public and private actors, generated broader support for subsequent actions, helped efforts to secure/seek funding for climate adaptation actions, developed material resources to support planning, and promoted learning among participants. This assessment also reinforces prior work showing that deliberative planning tools/processes are conducive to developing adaptive capacities; processes should be closely coordinated with regular governance activities to impact policy and action; adequate time for deliberation needs to be budgeted; participants need support to "think outside the box" and consider adaptation strategies that are both incremental and transformational as well as highlight potential undesirable consequences of adaptation; and processes, like VCAPS, produce actionable outcomes when participants agree on the immediacy of the issue. We conclude with observations about the need for evaluation of participatory processes and the challenges of defining success of tools to support municipal climate change adaptation planning.

In South Carolina, sea level rise and sinking land surface means that the coastal areas of the state will experience a relative sea level rise ranging between approximately 0.5 to 1.5 feet in 2030, 0.75 to 3.2 feet in 2050, and 1.75 and 10.8 feet by 2100. These ranges are based on scenarios that encompass uncertainties about physical processes and about future levels of greenhouse gas emissions. They cover low rates of sea level rise and low greenhouse gas emissions to high rates of sea level rise and high greenhouse gas emissions to convey the future risks for the purpose of long-term decision making. Many communities are already experiencing impacts of recurrent flooding, sometimes called nuisance flooding, associated with “king tides” and meteorological events. For the state and county and local governments, sea level rise and increased flooding pose a significant, costly, and persistent threat to roads and highways. These natural disasters and chronic flood damages will inevitably encourage South Carolinians to reconsider the status quo of road maintenance and repair. Under projected sea level rise, repetitive or severe damages will lead to tough decisions about whether to decrease routine maintenance, transfer control of the roads to different government authorities, or abandon existing roads.Although the South Carolina Department of Transportation (SCDOT) owns more than 50% of the roads and highways across the state, adaptation efforts related to road maintenance and abandonment can be expected to occur at both the state and local levels. The state, towns, cities, and counties have legal responsibilities to maintain roads, and they all certainly have an interest in ensuring that roads are safe and maintained. This white paper discusses how South Carolina law may impact local governments that are facing the effects of coastal flooding on their public roadways. The paper first outlines the statutory basis for road ownership and the duties that flow from such ownership. It then reviews potential causes of actions resulting from the breach of duties of maintenance and good repair. Finally, it addresses the procedural requirements for formal road abandonment and takings liability from loss of road access.

Sea level rise and sinking land surface means that the coastal areas in the South Atlantic are very likely to experience a relative sea level rise of one to four feet in the coming century. Many communities are already experiencing impacts of recurrent, sometimes called nuisance flooding, associated with “king tides” and meteorological events. For the state and county and local governments, sea level rise and increased flooding pose a significant, costly, and persistent threat to roads and highways. These natural disasters and chronic flood damages will inevitably encourage decision-makers to reconsider the status quo of road maintenance and repair. Under projected sea level rise, repetitive or severe damages will lead to tough decisions about whether to abandon existing roads, decrease routine maintenance, or transfer control of the roads to different government authorities. To begin to understand the potential scope of the problem, this white paper presents an analysis of roadways in coastal cities and counties in North Carolina, South Carolina, and Georgia vulnerable to sea level rise under one-, two-, and three-foot scenarios, using sea level rise data from NOAA’s Office for Coastal Management Sea Level Rise Viewer Data Download.

This study presents the first comparison of Landsat 8 Operational Land Imager (OLI) and Sentinel-2 Multispectral Instrument (MSI) in identifying soil salinity using soil physiochemical, spectral, statistical, and image analysis techniques. By the end of the century, intermediate sea level rise scenarios project approximately 1.3 meters of sea level rise along the coast of the southeastern United States. One of the most vulnerable areas is Hyde County, North Carolina, where 1140 km(2) of agricultural lands are being salinized, endangering 4,200 people and $40 million USD of property. To determine the best multispectral sensor to map the extent of salinization, this study compared the feasibility of OLI and MSI to estimate electrical conductivity (EC). The EC of field samples were correlated with handheld spectrometer spectra resampled into multispectral sensor bands. Using an iterative ordinary least squares regression, it was found that EC was sensitive to OLI bands 2 (452nm - 512nm) and 4 (636nm - 673nm) and MSI bands 2 (457.5nm - 522.5nm) and 4 (650nm - 680nm). Respectively, the R-Adj(2) and Root Mean Square Error (RMSE) of 0.04-0.54 and 1.15 for OLI, and 0.05-0.67 and 1.17 for MSI, suggests that the two sensors have similar salinity modelling skill. The extracted saline soils make up approximately 1,703hectares for OLI and 118hectares for MSI, indicating overestimation from the OLI image due to its coarser spatial resolution. Additionally, field samples indicate that nearby vegetated land is saline, indicating an underestimation of total impacted land. As sea levels rise, accurately monitoring soil salinization will be critical to protecting coastal agricultural lands. MSI's spatial and temporal resolution makes it superior to OLI for salinity tracking though they have roughly equivalent spectral resolutions. This study demonstrates that visible spectral bands are sensitive to soil salinity with the Blue and Red spectral ranges producing the highest model accuracy; however, the low accuracies for both sensors indicate the need of narrowband sensors. The HyspIRI to be launched in the early 2020s by NASA may provide ideal data source in soil salinity studies.

This report is an authoritative assessment of the science of climate change, with a focus on the United States. It represents the second of two volumes of the Fourth National Climate Assessment, mandated by the Global Change Research Act of 1990.

Vibrio species are marine bacteria that occur in estuaries worldwide; many are virulent human pathogens with high levels of antibiotic resistance. The average annual incidence of all Vibrio infections has increased by 41% between 1996 and 2005. V. vulnificus (Vv), a species associated with shellfish and occurring in the US Southeast, has ranges of temperature (16-33 °C) and salinity (5-20 ppt) dependencies for optimal growth. Increased water temperatures caused by atmospheric warming and increased salinity gradients caused by sea level rise raise concerns for the effect of climate change on the geographic range of Vv and the potential for increased exposure risk. This research combined monthly field sampling, laboratory analysis, and modeling to identify the current occurrence of Vv in the Winyah Bay estuary (South Carolina, USA) and assess the possible effects of climate change on future geographic range and exposure risk in the estuary. Vv concentrations ranged from 0 to 58 colony forming units (CFU)/mL, salinities ranged from 0 to 28 ppt, and temperature from 18 to 31 °C. A significant empirical relationship was found between Vv concentration and salinity and temperature that fit well with published optimal ranges for growth for these environmental parameters. These results, when coupled with an existing model of future specific conductance, indicated that sea level rise has a greater impact on exposure risk than temperature increases in the estuary. Risk increased by as much as four times compared to current conditions with the largest temporally widespread increase at the most upriver site where currently there is minimal risk.