Southeast
climate highly influential scientific assessment government
Steven G. McNulty Jeremy S. Hoffman Claudia Brown Kathie D. Dello Pamela N. Knox Aranzazu Lascurain Carl Mickalonis Gary T. Mitchum Louie Rivers III Marie Schaefer
The Fifth National Climate Assessment is the US Governmentâs preeminent report on climate change impacts, risks, and responses. It is a congressionally mandated interagency effort that provides the scientific foundation to support informed decision-making across the United States.
https://nca2023.globalchange.gov/icons/apple-touch-icon.png
Fifth National Climate Assessment
A Growing Region Means Increased Climate Risks

All but one of the Southeastâs statesâMississippiâexperienced population growth over the last decade, and most of the fastest-growing large US cities are located in the region.40 Even under scenarios with moderate population growth (e.g., Shared Socioeconomic Pathway [SSP] 2), the regionâs population is expected to increase (Figure 22.1).41

Southeast land cover equal to about 1.7 million football fields changed from forested to developed between 1985 and 2019, more than in any other NCA region (Figure 22.2a; Ch. 6). Urbanized land cover is estimated to increase by more than 9% throughout the region by 2060, based on urban area growth trends during 1990â2010,42 further threatening the regionâs unique terrestrial and aquatic biodiversity (Figure 22.2b; KM KM 8.1).

Unconstrained exurban and suburban sprawl will further expose human development to weather- and climate-related risks such as wildfire,44 hurricanes,45 floods,13,46 intensifying thunderstorms,47 and tornadoes.48 Growth along the regionâs coastlines49 has increased the population exposed to coastal-specific climate threats.13,50,51,52,53 Although the Southeast has historically experienced more billion-dollar disaster events than the rest of the country54 and has weathered multiple hurricanes since 2018 (Figure 22.3), there is considerable regional variation among residentsâ perceptions of whether climate change will personally harm them.55,56

Some of the Southeastâs growth follows patterns of urban renewal, with affluent and young people returning to urban areas and displacing under-resourced communities to suburban and rural areas.57 As a result of this displacement and long-standing underinvestment, under-resourced communities face more environmental hazards and increasing risks (Figure 22.4b)3,13 but have less access to climate-ready infrastructure such as housing (Figure 22.4a), dwellings with strong building codes58 that minimize disruption during storms,59,60 public transit,61 community resource centers for heat and cold relief,62 and up-to-date stormwater management systems.63 These communities often also lack a well-resourced local and/or state governmental workforce64 to analyze, plan for, and mitigate risks (KM 20.1).16,17,18,65,66

Inland and Coastal Flooding Threatens the Present and Future

Southeast flood risk is inequitably distributed due to both climate and non-climate stressors. Physical stressors such as increases in rainfall, temperatures, and sea level, in addition to land cover change, exacerbate flood risks (KM 4.2),13,50,67,68 while social and economic policies, including institutional investments and disinvestments, differentially shape risk, vulnerability, and exposure to flooding.69,70,71 Compounding preexisting social and economic disparities are changes in precipitation patterns. For instance, shifting autumn precipitation patterns have been attributed to human-caused climate change,72 and some Southeast counties with higher social vulnerability are experiencing more frequent flooding.73

Mandatory flood risk disclosure requirements largely depend on state-by-state policies,74 and virtually all requirements apply only to home sales. Millions of rental housing units in the region are within counties that have high Expected Annual Loss ratings from FEMA,75 and confidence is growing that areas currently populated by communities of color, who also are more often renters, will face disproportionately high future flood risks (Figure 22.4).3,13 Furthermore, other forms of housing that are vulnerable to climate risks include mobile homes and manufactured housing, which are concentrated in the Southeast.40,76,77 These populations tend to face more barriers to accessing flood insurance and federal flood disaster assistance and more often experience adverse outcomes during disaster recovery, due in part to the lack of disaster relief programs for renters and the rising cost of flood insurance.78,79,80 Additionally, the potential overvaluation of coastal residential housing stock makes it even more challenging to move people out of harmâs way due to the upper limits placed on the amount of compensation these programs can offer and peoplesâ reluctance to sell these properties and lose rental revenue. For example, in Miami-Dade County, Florida, the total overvaluation of properties is $3.9 billion, and in nearby Duval County, where Jacksonville is the county seat (Figure 22.5), overvaluation exceeds $420 million.81 Across the Southeast, the average total overvaluation of properties is estimated to be around $110 million per county. Florida has the highest statewide total average overvaluation at $749 million, while Mississippi has an undervaluation of $20 million.81

Flooding impacts infrastructure and, in turn, public health. Injury, illness, and death can result from exposure to mold from floodwater damage,82,83 onsite wastewater treatment system failures,84 and carbon monoxide poisoning from misuse of generators for emergency power.85,86,87 In addition, healthcare facilities may be damaged by flooding or unable to handle an influx of demand.88,89 Damage to roads and bridges might prevent access to these facilities, disrupt the supply of medications and equipment,90 and hinder a communityâs lifeline to emergency services and evacuation routes.91

Tropical storms and hurricanes have been responsible for some of the Southeastâs biggest and most damaging flooding events since 2018 (Figure 22.3). The likelihood of hurricanes slowing down or stalling near the coast has increased, exacerbating the rainfall-related flooding threat from these systems.92 However, the impact of climate change on slowing down or stalling tropical storms remains uncertain,92 although some simulations indicate a potential slowdown of Atlantic storms due to climate change,93,94 including near the Southeast US coast.95,96 In addition, rapidly intensifying hurricanes have presented challenges for implementing evacuations,97 and the frequency with which Atlantic hurricanes rapidly intensify may be increasing in response to long-term human-caused climate change.98 Also, there is evidence of increased intensification rates near the US Atlantic coast, which may continue into the future.99 There have been significant improvements in understanding how nontropical systems,100 atmospheric rivers,101,102,103,104,105 past and future El NiÃ±oâSouthern Oscillation patterns,106,107 flash flooding,73,108 and urban environments109,110,111,112,113 add to the Southeastâs risk of extreme precipitation and flooding.

With additional global warming, more North Atlantic hurricanes are expected to strengthen to at least Category 4 intensity and to undergo rapid intensification, sea level rise is expected to worsen storm surge inundation, and tropical cycloneârelated rainfall is expected to increase.93,114,115,116,117 The likelihood of storms making landfall could increase, which may offset the potential decrease in the total number of storms and overall exacerbate impacts.118 However, some uncertainty remains regarding the expected degree of change in hurricane activity impacting the Southeast. Additionally, estimates suggest that some seasonal, annual average, and extreme precipitation amounts across the Southeast will increase, driven mainly by more extreme events (e.g., precipitation of 3 inches or more in 24 hours) at higher levels of warming.20,67,119

Some Southeast communities plan for these extreme events with an outdated understanding of climate-related risks.68,120,121 Sewer infrastructure is built to accommodate a particular amount of rainfall over a specified time, and current estimates of precipitation intensity, frequency, and duration generally do not consider future projections of these metrics, posing a significant challenge to civil engineers.122,123 Estimating future precipitation characteristics and their impact on sewer infrastructure in the Southeast is primarily conducted on a state-by-state basis and relies on different scientific approaches,121,124 further complicating the development of design standards for climate-ready infrastructure (Figure 22.5; KM 12.2).120

Extreme rainfall that occurs at the same time that ocean water inundates populated areas (e.g., because of high tides or storm surges) creates compound flooding events, which can result in decreased property values125 and roadway obstructions that can hinder first responders (KM 9.2).66,126 Compound flooding events already affect low-lying areas in the coastal plain,93,127 and the Intermediate-Low and Intermediate sea level rise scenarios for the Southeast project a higher frequency of compound flooding by midcentury in regions along the Atlantic coast.128

Tide gauges throughout the Southeast indicate that relative sea level rose by 6 inches during the 1970â2020 time period, with some variation across the region.51 The average range of sea level rise by 2050 relative to 2000 in the Southeast (Low to High scenarios)51 is 16â23 inches (0.40â0.58 m). This increases to a range of 2.2â7.3 feet in 2100 relative to 2000 under the same scenarios.51 These regional estimates are higher than the projected global average rise due to regional variations in land motion, excessive groundwater pumping,129 and the effects of sea level changes caused by changes in ocean currents.51 For example, overall sea level rise projections by 2050 are 22â32 inches for Grand Isle, Louisiana, 10â19 inches for Jacksonville, Florida, and 15â22 inches for Outer Banks, North Carolina. High tide flooding events in the Southeast may increase by a factor of 5â10 by 2050 due to sea level rise (Figure 22.5).51 However, many communities will experience comparable increases in these events before 2050 due to changes in tides that exacerbate sea level rise.52 Saltwater intrusion from rising sea levels has already degraded the health of coastal forests and estuaries while reducing their ability to store carbon,130,131 and increased soil salinity has reduced yields in the remaining range and farmland.132 While there is uncertainty in how global ice sheets will respond to additional global warming and thus ultimately determine longer-term sea level rise, the Southeast could experience 3.1â13.2 feet of sea level rise by 2150.51

Art × Climate

Daniel Kariko

Last Camp on Isle Derniere, Louisiana

(2017, photography)

Artist’s statement: Louisiana is experiencing the highest rate of coastal erosion in America. Major storms, including Katrina and Rita in 2005, and Ida in 2021, have drastically changed the geography of Louisianaâs coast. Many of South Louisianaâs communities, including Indigenous Americans, Cajuns, and Asian Americans are affected by loss of natural resources, economic impact, and direct loss of property. People of Louisiana are closely defined by the landscape they inhabit. Yet every year, small local communities gradually sink into the wetlands. This subject is a proverbial âcanary in the mineâ for issues that affect the entire planet.

View the full Art × Climate gallery.

Artworks and artists’ statements are not official Assessment products.

Indigenous Communities: Loss and Leadership in a Rapidly Changing Region

Indigenous communities have long faced displacement from and loss of cultural and desirable lands from settlers and government (Figure 16.1). Settler colonialism and climate change are forcing the displacement of Indigenous communities once again, causing stress and grief (KM 16.1). Indigenous communities experience substandard housing and infrastructure, as well as limited insurance coverage, which increases their vulnerability to climate stressors (KM 16.2).134 In addition, land dispossession in the Southeast has impeded Indigenous Peoples from enduring climate hazards and deprived them of the benefits of the natural environments they once stewarded.135,136,137,138

Climate change and a shift from Indigenous-managed cultural landscapes to settler-managed landscapes threaten cultural knowledge and practices.136 This shift can be seen in the loss of plants and animals of cultural significance to Southeast Indigenous communities (Figure 22.2; Box 22.3). This loss has contributed to decreased physical and mental well-being as Tribal citizens have had to shift away from subsistence lifestyles that connect them to their cultural landscapes and contribute to cultural continuance.22,139 Climate change also alters the ranges of native plants while enhancing the growth of invasive species that may out-compete them.140 The loss of native species adversely affects Indigenous populations who rely on these resources for subsistence or cultural value,141 such as coastal communities with economies driven by forests or fisheries.142 However, Tribal Nations are finding ways to lead in responding to climate change (KM 16.3) while exercising their rights to cultural continuance and sovereignty through numerous actions and projects, including revitalizing rivercane ecosystems (Box 22.3).

Southeastern archaeological sites reveal a rich history of how Tribal Nations have met challenges similar to those they are experiencing now by using their Indigenous Knowledges.143 However, many of these sites are exposed to the threat of rising sea level because they are located in coastal lowlands.144 A sea level rise of approximately 3 feet (about 1 m) could result in the loss of more than 13,000 historic and prehistoric archaeological sites (with significantly more lost under more severe scenarios) while directly harming contemporary Indigenous communities across the Southeast.144 Sea level rise also threatens coastal marshes in the Southeast more than anywhere else in the US.145 The potential loss of these marshes, teeming with biodiversity and critical ecosystem services, could adversely affect the communities that depend on them. The ability of marshes to move (or âmigrateâ) landward in response to sea level rise will depend on the availability of onshore land that in many cases is already developed. Planning for the migration of marshes will require a further understanding of their dynamics, as well as social trade-offs to accommodate their migration into new areas.145

Moving Out of Harmâs Way, Protecting Existing Communities, and Planning Ahead for Growth and Potential Resettlement

The Southeast is responding to climate threats; however, these actions are spread unevenly across the region (Figure 31.1). Many communities are adopting adaptation plans, including anticipating population growth due to climate-driven relocation.146,147,148 Tribal governments achieve greater success in developing comprehensive climate adaptation plans when joining strong cross-Tribal networks that share knowledge of effective strategies.149 However, Southeastern adaptation plans (especially for drought and heat) are less comprehensive than those in other regions.150,151,152,153

Adaptation actions include avoidance, planned relocation, protection, accommodation, or some combination of these. Avoidance involves limiting development in hazardous areas. Retreat from the coast or riverine floodplains involves removing infrastructure, housing, and public facilities from hazardous areas over time while limiting future development. Protection strategies use physical infrastructure like seawalls, levees, and beach nourishment, although these may not provide long-term protection if designed for past climate conditions.154 Accommodation involves elevating structures or using building materials that can withstand being submerged by floodwaters or are less prone to damage when exposed to fire (Figures 22.6, 22.7).

Funding needed to implement adaptation projects remains elusive for many communities, especially those with limited resources and high levels of preexisting social vulnerability.80,155 One strategy for advancing climate adaptation is applying for FEMA Hazard Mitigation Assistance (HMA) grants.156,157,158 However, state hazard mitigation officers who manage these grant programs have described differing levels of capacity to help local governments develop and implement HMA grants.16 While FEMA updated its hazard mitigation planning guidance in 2022 to require that local governments and states address equity and future conditions as part of their new strategic plans,156 the impacts of these changes have yet to be effectively assessed relative to the quality of the plans. Despite these challenges, a growing number of localities are factoring intensifying climate-related stressors into adaptation plans35,159,160,161 and helping guide new policy (Box 22.2).

Current Tools Could Ensure Equitable Adaptation

There are several types of climate adaptation tools available to communities in the Southeast, including buyouts, information clearinghouses, land use policies, and city design and planning (Figures 22.6, 22.7).

Buyoutsâacquiring hazard-prone housing that is demolished and converted to open spaceâare widely recognized as one of the most cost-effective strategies for reducing future losses,162,163 including those associated with adapting to a changing climate.164 However, while buyouts do require that the land be converted to open space after purchase, applying other proactive land-use planning techniques that guide development to safer locations or limit future growth in hazard-prone areas remains an uncommon practice.165,166 As a result, there remains considerable uncertainty around whether communities are actually reducing risk when accounting for the losses avoided with buyouts relative to increased hazard exposure associated with new development in hazard-prone areas.167,168,169 For example, some buyouts resulted in people relocating to an area of similar risk as their original dwelling,170,171 and relocation in a broader context has meant moving from one risk zone to another.172 BuyoutsÂ can also reduce a communityâs tax base, which can be particularly devastating in smaller jurisdictions with limited revenue to support governmental services.173 Questions of equity in buyouts include whether buyouts are preferred byÂ residents, whether choosing to participate in buyouts is in their best interest, and whether frontline communities are involved in deciding how and where buyouts occur (KM 20.5; Figure 20.3).174,175,176,177,178,179 Additional buyout challenges include the long-term management of resulting open spaces, tracking buyout land in a given area, and strategies to achieve co-benefits such as creating climate-resilient recreation amenities like parks, greenways, water retention areas, and ballfields.180,181,182 Buyout migration and relocation from one place may also exacerbate local housing pressure in another. For example, in Miami, wealthier individuals are moving from higher-flood-risk coastal areas to safer higher-elevation areas, increasing inland property values and displacing residents,183,184,185 although the exact pressures driving gentrification and displacement within any community are complex.186,187 There is evidence that points to the migration of some Black residents out of floodplains in the Southeast, including the case of Edgecombe County, North Carolina, where the Town of Princeville, discussed in Box 22.1, is located.53

A growing number of climate adaptation resource clearinghouses are available (KM 31.4), and they include Southeast case studies.188,189 In addition, Southeast-focused organizations like the Southeast Climate Adaptation Science Center, USDA Southeast Climate Hub, and the Southeast and Caribbean Disaster Resilience Partnership provide resources needed to advance adaptation strategies, including resources for rural and/or under-resourced communities.18,64 Some climate change planning documents even now center on additional considerations such as equity in their frameworks.190 However, inequitable access to resources and constraints on workforce capacity to effectively use these tools can also lead to unequal progress toward implementing strategies across communities.

Climate-resilient community design principles are being employed by urban planners, landscape architects, and architects, as well as by an increasing number of municipalities (Figures 22.6, 22.7, 12.8).

Underlying Health Issues and History in the Southeast

Public health status is an important indicator of vulnerability to climate stressors,190,195 and Southeasterners are consistently ranked among the unhealthiest in the Nation, with shorter life expectancies than the US average (Figure 22.8).196 Health disparities in the Southeast are related to various social determinants of health, such as lack of access to healthcare, low socioeconomic status, and poor health behaviors (e.g., smoking and drug and alcohol abuse).197 Sedentary lifestyles are reinforced by the quality of the surrounding built environment: the Southeast is home to 8 of the 10 least-walkable cities,198 15 of the 20 most dangerous cities for pedestrians,199 and 4 of the top 10 deadliest states for cyclists in the United States.200

The Southeast has more Black residents than any other NCA region,40 and health-related challenges faced by communities with majority Black populations differ from those with majority White, Hispanic, or Asian populations.201 Communities with majority Black populations tend to have even lower life expectancies and less access to resources that promote health, such as grocery stores, safe places to exercise, and quality healthcare than whiter and wealthier populations.202 These communities also have fewer opportunities for economic prosperity (Figure 22.12), fewer employment opportunities, limited access to quality education, and higher unemployment rates, all of which shape health outcomes.11 Black communities in the Southeast, therefore, shoulder a disproportionate level of health risk associated with climate change.3,12

Keeping Cool as Temperatures Rise

Extreme heat affects everyone, but particularly at risk are pregnant people;203,204,205 people with heart and lung conditions;206,207 older adults and young children;208,209 people with mental health conditions;210,211 outdoor workers in construction, agriculture, and the service industry;212,213 athletes;214,215,216 and populations who lack adequate shelter or are incarcerated.217,218

Southeasterners rely on air-conditioning to cool living spaces, and air-conditioning demand is expected to grow across the Southeast as the climate warms.219 However, air-conditioning prevalence varies along racial and economic lines.220 Furthermore, the Southeast has high rates of households that experience energy insecurity.221 While the Southeast has the lowest energy rates in the US, households there pay the countryâs highest energy bills.222 High energy bills disproportionately impact rural and under-resourced residents, elderly residents on fixed incomes, and communities of color (Figure 22.9).222 Historical de facto as well as de jure segregation policies such as redliningâthe New Dealâera practice of classifying communities with significant Black, Asian, and immigrant populations as hazardous for financial investmentâneighborhood housing covenants, and urban renewal have had lingering effects on frontline communities in the Southeast, resulting in their low proportion of homes that are energy efficient and affordable.222 There is evidence that the number of blackout events (power outages) affecting more than 1,000 residents for more than one hour due to increasing energy demands and extreme weather events is increasing.223,224,225 The Southeast has experienced many such blackout events annually and during the warm season (MayâSeptember) since 2011 (Figure 22.10).226

Public cooling centers are temporary health interventions for those without adequate air-conditioned shelter on exceptionally hot days (KM 15.3). However, in some areas of the Southeast, these centers are not located within walking distance of the populations most in need.228 Furthermore, the Southeast has the lowest public transportation access for households without a private vehicle.229

Heatwaves in the Southeast are happening more frequently and are occurring during a longer heat season, with some cities also showing increasing trends in their duration and intensity (Ch. 2).3,230,231 The number of extreme warm days (above 95Â°F) is expected to continue increasing with every increment of global warming (Figure 22.9b; Ch. 2). Wet-bulb globe temperature (WBGT)âwhich measures the combined effects of temperature, humidity, wind, and sunlight on thermal comfort and which may be a better metric for the Southeast than more traditional measures of extreme heat232,233âhas already increased due to anthropogenic climate change in parts of the region234,235 and is expected to increase across the region throughout this century.230,235 Additional heat stress within cities can be attributed to the urban heat island effect (Figure A4.4), whereby cities experience warmer temperatures than outlying rural areas and some neighborhoods within a city are hotter than others.236,237 Heat island intensities across the Southeast are systematically higher in formerly redlined communities5 and in counties with higher proportions of Black, Hispanic, and Asian residents, people with education no higher than a high school diploma, people with lower median incomes, and single-parent households.238 However, there is a lack of consistent and appropriate thresholds used to evaluate heat risk. For example, most work-related heat illnesses across five Southeast states occurred below the heat index range designated as dangerous by the National Weather Service.239

Climate change is increasing the risk of multiple dangerous weather events occurring simultaneously or in close proximity, resulting in worsened health effects (Ch. 15). An example of this is when a heatwave occurred after Hurricane Laura devastated the coast of Louisiana in 2020, resulting in at least eight deaths due to heat and an increased risk of heat-related illness, particularly for those who lost electricity and outdoor workers assisting with the recovery.240

In response to heat threats, Miami has institutionalized the first city heat officer to coordinate heat preparedness and response efforts to reduce impacts to the most vulnerable.

Blowing in the Wind

In the Southeast, climate change threatens Clean Air Act improvements by creating favorable conditions for increases in smog241,242,243 and wildland fire emissions.244,245,246 The Southeast already has significant amounts of particulate matter (PM2.5; Figure 22.11a) as a result of anthropogenic pollutants247 and extensive vegetation,248 and the associated health effects are experienced disproportionately by communities of color and populations with lower socioeconomic status (Ch. 14).249,250 Future premature deaths due to PM2.5 in the region could be avoided through significant emissions reductions, even when considering future warming (Figure 22.11b; KM 14.3).3,251,252 This is particularly relevant to the Southeast, which is projected to have the highest number of premature deaths due to climate-induced increases in PM2.5 and ozone exposure.3,251,252

In addition, airborne pollen can pose significant health risks to populations living in the southeastern United States.253 Since 1992 in Atlanta, tree pollen concentrations have increased by approximately 4% in the spring and 10% in the fall, and weed pollen has increased by approximately 5% in the spring.254 Some species of trees and weeds are exhibiting an earlier and longer pollen season, correlating with warmer spring temperatures.254 Pollen increases pose significant health risks, including aggravating respiratory conditions such as asthma, which has been linked to a loss of school and work days (KM 14.4). These health risks are expected to worsen as pollen seasons shift earlier and lengthen due to climate change (KM 14.4; Figure 8.2).

Fire Danger

Wildfire risk disproportionately disrupts the lives of socioeconomically disadvantaged communities in the Southeast.2 As more people inhabit forested areas, there is an attendant increase in wildfire risks to human health and property.255 More hot days may also exacerbate soil moisture deficits, leading to heightened wildfire risk in the region.244,256 Rural, mountainous portions of the Southeast are more exposed to and less equipped for mitigating wildfire.257

Forest managers conduct controlled, low-intensity fires, known as prescribed burns, to reduce the amount of deadwood and vegetation, thereby managing wildfire risk.258 While the impacts of wildfires on air quality are widely recognized (KM 14.2), less is known about the impacts of prescribed burns versus wildfires on air quality.246,259 Prescribed burns reduce the risk of wildfire damage to the environment, homes, and infrastructure, although areas with intensive prescribed burning tend to be near communities with higher social vulnerability scores, which subsequently experience more negative health outcomes from the smoke.260,261 As conditions favorable for wildfire and unfavorable for prevention become a greater risk for southeastern communities due to a warming and drying climate,256,262 communities may need to invest in more robust equipment and infrastructure. In 2016, wildfires in western North Carolina and eastern Tennessee highlighted the connection between exceptional drought and fire in the Appalachians.263 Power outages and damage to PVC pipelines that supplied water to sprinkler systems led to a lack of water to combat fires, resulting in more significant damages.264,265 That year, nearly 50% of US wildfires occurred in the Southeast, yet these fires contributed to only 29% of the total area burned that year, indicating that southeastern wildfires are smaller.244,246,258

Rolling Red Tides

Harmful algal blooms (HABs), also known as red tides or brown tides, occur in fresh, brackish, and salt water.266 HABs result from the overgrowth of algae due to runoff water containing excess nutrients from agriculture and lawn maintenance, rising water temperatures, and other land-use development.267 Since 2011, large masses of sargassum, which can fall under a HAB classification, have been increasing from Florida across the Caribbean, causing harm to coastal socialâecological systems. This problem could be intensified by rising temperatures from climate change.268,269 HABs have significant negative impacts on human and animal health, as well as broad-reaching environmental and economic effects.270,271,272,273

Humans may experience various health issues from HAB exposure, such as diarrhea and headache.273 HAB events also threaten national and local economies, as tourist areas become less desirable to visit.271 Fisheries and aquaculture industries suffer from the loss of marine life and decreased species diversity as ecosystems are disrupted and hypoxic conditions occur,274,275,276 and consumers are potentially exposed to seafood poisoning.277,278 On Floridaâs Gulf Coast, prolonged algal events have caused a devaluation of coastal properties.270,272

More Than Just a Bug Bite

Temperature and precipitation changes are anticipated to shift the geographic distribution and season of certain disease-carrying mosquitoes and ticks in the Southeast (KMs 15.1, 8.2). For ticks that carry diseases such as Lyme and Rocky Mountain spotted fever, models project varying shifts in ecosystem suitability in the Southeast depending on the species, land-use changes, and host abundance.279,280,281,282,283 Of particular concern are mosquito-borne diseases such as chikungunya, dengue, malaria, West Nile virus, and Zika virus. All have been documented in the Southeast and pose potential risks to human health.284 Black and under-resourced neighborhoods in Chatham County, Georgia, were identified as hotspots for West Nile virus, as well as being home to communities with limited understanding of personal risk and protective measures against mosquitoes.285,286

The MindâClimate Connection

The Southeast is home to 5 out of the 10 highest-ranked states for the prevalence of mental illness287 and 8 out of the 10 lowest-ranked states for access to mental healthcare services.288

Climate change significantly affects mental health as a result of 1) acute disaster events such as hurricanes, floods, and wildfires (KM 15.1); 2) long-term changes such as drought289 and heat stress;210 and 3) existential threats of long-lasting climate change impacts that make people feel less secure in their physical environment.290 Those who are either directly impacted by or concerned about the threat of climate change to themselves or others may experience âeco-anxietyâ or âclimate anxiety.â291,292

While extreme weather events commonly occur in the Southeast, climate change has increased their frequency and magnitude (Ch. 2), causing residents to face repeated trauma and displacement at an unprecedented level, which can lead to stress and the onset of new psychiatric disorders or the worsening of preexisting mental health conditions,293 especially among children and under-resourced and BIPOC residents.290,294,295 The Florida Department of Health in Monroe County conducted an evaluation of its emergency shelter effectiveness in serving people with particular access and functional needs and found significant room for improvement, leading to updates to strategic planning processes and procedures related to the operation and communication of specialty emergency shelters to ensure more equitable access to shelter services.

Economic Risks in the Southeast: âLess Money, More Problemsâ

Across the Southeast, disaster losses have increased over the last several decades, primarily due to rapid growth in hazardous areas that are driven, in part, by national, state, and local policies that incentivize development in such areas.166,296,297 Rising disaster costs negatively impact local and regional economies, some of which are already affected by limited upward economic mobility for their population, as well as by limited administrative, institutional, and social capacity (Figure 22.12). Moreover, these multisectoral impacts are expected to worsen substantially due to climate change,298 especially in the Southeast region (Figures 22.13, 22.14, 19.1; KM 19.1).

Losses attributed to climate change are expected to increase as rapid development continues to occur in hazardous areas, particularly along coasts (Figure 22.4b),299 while rural residents face increasing levels of isolation and economic decline (Figure 22.12).62

Place-based economies that are located in hazardous areas and are reliant on unique ecological systems (e.g., aquaculture, farming, and recreation/tourism) face numerous challenges, including the uncertainties associated with the stability of freshwater and saltwater ecosystem services that support business and cultural attachment to place.301 For example, some fishing communities are facing threats to fishing infrastructure due to sea level rise and more intense coastal storms, as well as threats to fisheries stock habitats that are vulnerable to the effects of a changing climate, such as increasing bottom-water temperatures.142,302,303 Meanwhile, inland towns and cities with ecotourism attractions also face significant economic losses due to increased flash flooding,73,108 including lower-income rural areas in Appalachia, as exemplified by the 2022 floods in eastern Kentucky. Rapidly growing urban centers in the Southeast are increasingly vulnerable to drought and the challenges tied to the provision of water for residents and businesses.304,305,306,307 The Southeast is more drought-prone than other parts of the eastern US due to higher rates of evapotranspiration.308,309 Evapotranspiration is expected to increase due to future climate warming (Ch. 2). Alabama citiesâ drought plans were evaluated as less comprehensive and lacking pre-drought preparation compared to those of California cities.152 In rural, agriculturally dependent economies, increased heat, drought, and water-laden tropical storms currently threaten the productivity of crops and livestock (KM 22.4),310,311 as well as the health and livelihoods of workers, who tend to be Latino migrants.312 Future global warming will increase this threat, potentially further reducing labor productivity and costing billions of dollars, particularly in the already hot and humid Southeast (KM 2.2).212,313 The Southeastâs economy relies on the regionâs ports, rivers, rail, air, and road networks, which are at risk from sea level rise, flooding, extreme heat, drought, and other climate-related hazards.61,314 However, proactive adaptation can offset potential future climate-related damages substantially (Figures 22.13, 22.15, 22.17). Unplanned disruptions to these systems can potentially affect consumer pricing of goods, services, and livelihoods throughout the region and elsewhere (Figure 22.16).315,316

Supply Chain Impacts Affect Places Outside the Southeast

There is an urgent need to address climate change risks to global supply chains (Focus on Risks to Supply Chains; KM 19.1).318 In the Southeast, climate changeâinduced transportation infrastructure risks affect all modes (e.g., air, water, highway, rail, and even pipelines; Figures 22.15, 22.16; Ch. 13). Transportation agencies across the region appear to be planning for infrastructure improvements on different schedules and often lack the capacity to include climate data in the planning process (Ch. 13).319 Coordinated and proactive adaptation strategies could offset significant future damage to these systems (Figures 22.15, 22.17).317,320,321

Many Southeast roadways and rail lines are located along waterways and frequently cross bodies of water, making them vulnerable to potential floods and heat-related impacts. High future costs are expected if no adaptive investments are made today (Figures 22.15, 22.17).317 Inland navigation and the Mississippi River are critical to supply chains in the Southeast and much of the central portion of the United States, as evidenced by the 2021 closure of the Interstate 40 bridge over the Mississippi River at Memphis, Tennessee.322 Unscheduled lock outages resulting from floods, droughts, earthquakes, or hurricanes can cause cascading impacts. For example, an unplanned outage of the Calcasieu Lock in southern Louisiana would affect economies in 170 counties and 18 states (Figure 22.16).315,323 In the Southeast, manufacturing facilities for industries such as automotive (including electric vehicles and charging stations),324 solar panels, agriculture,325 and construction often rely on parts or materials originating from other locations, including some from international sources. The Mississippi River serves as a gateway to the Nation for imports of such materials and exports of goods such as agricultural products. In recent years, low-flow conditions due to regional droughts on Southeast waterways such as the Mississippi have halted or delayed the movement of barges carrying bulk goods, with regional and national implications (Figures 22.14, 22.16).326,327

Disruptions can impact not only the delivery of finished goods and products to customers but also production and the livelihoods of individuals working in jobs dependent on materials from other locations that may not arrive in time, leading to revenue loss and even potential job loss if disruptions become regular and significant enough. The impacts of climate change on supply chains include not only disruption to systems and additional costs associated with the transportation of goods but also potential health impacts to workers in industries that require working outdoors, such as agriculture,325 fisheries, construction, and last-mile delivery,328,329 who may be exposed to extreme heat or cold. Workers in these jobs may require additional heating or cooling or adjustments in shift times to avoid exposure to adverse weather conditions (KM 22.2; Ch. 19).330

Furthermore, the Southeast is a hub of activity for oil refineries that provide fuel to the eastern half of the United States.331 Climate change is expected to negatively impact not only refineries that are located along the Gulf Coast but also the distribution networks of the petroleum products that many rely on for emergency services, backup power generation, air travel, and more.60,332,333

Securing Economic Vitality

Protecting businesses and urban and rural infrastructure investments may require adopting a combination of adaptation measures (KM 22.1). However, to avoid unintended disparities in service provision, these infrastructure investments should consider the needs of frontline communities in their design criteria.334 For instance, Charleston, South Carolina, has explored questions surrounding the appropriate selection of adaptation measures, including protection techniques such as a seawall versus a greater reliance on nature-based solutions.

Justly transitioning to a low-carbon economy provides opportunities for businesses335 as well as labor,336 assuming that marginalized populations and women are included in this workforce to avoid the inequities of our current energy labor markets.337 Business and governmental agencies could commit to workforce programs for employees in the oil, gas, and coal-producing industries,336,338 as workforce training in green technology must address challenges associated with transitioning away from economies that are closely tied to a communityâs way of life.339,340 Additionally, ecosystem restoration and nature-based green infrastructure solutions (e.g., urban forestry, stormwater retention gardens, green roofs) may also provide meaningful job opportunities (Ch. 19).341 Key to adapting to climate change and leveraging new opportunities is the need for training and workforce development, which will require investment and prioritization (Ch. 19).

Agriculture is critical to the economy of the Southeast through its production of food and fiber and employment. In the United States as a whole, agriculture, food, and related industries contributed $1.26 trillion (in 2022 dollars; a 5.2% share) to the gross domestic product in 2019.342 In the Southeast, nearly 500,000 farms produced market sales of more than $83.8 billion (in 2022 dollars),343 and the regionâs agricultural products are consumed locally and exported throughout the United States and the world.344 Food systems distribute agricultural products throughout the region, although food deserts are present in urban and rural areas.345 Disparities in food distribution are especially pronounced in areas with concentrations of Black, Indigenous, and under-resourced communities.345

Climate Stressors on Agriculture and Food Systems

Climate change stresses agriculture and food systems (Ch. 11). Threats from a changing climate include both direct threats through impacts of climate extremes on crops, forests, ecosystems, and livestock and indirect threats through impediments to transportation, the health of outdoor workers and animals, degradation and loss of natural ecosystems, reduced productivity and loss of traditional crops, increased threats from invasive species and weeds, and loss of livelihood for vulnerable communities such as rural BIPOC farmers. For example, increased average and extreme high temperatures346 have led to increased heat stress on livestock325,347 and outdoor workers. Warmer winter temperatures have reduced the number of chill hours (the total number of hours a plant experiences temperatures below 45Â°F over the winter months), which are essential for fruit production,348 and have caused unusually early blooming of crops such as peaches and blueberries, which makes them vulnerable to damaging frost events. In spite of warmer winters, however, the change in the average date of the last spring frost is not consistent across the region.349

Higher temperatures, particularly overnight temperatures, have reduced crop yields,350 and these impacts are projected to worsen with additional global warming (Figure 22.19; Ch. 11). They have also led to an increase in the occurrence of drought in the region (Figure 22.18).351,352,353 The Southeast is the only region in the eastern half of the United States that is prone to extreme drought,308 and flash droughts occur with higher frequency there than in any other region.354 Longer-term droughts in the Southeast appear to be increasing in severity but do not appear to be occurring more frequently.355 Changes in climate conditions have also contributed to increased pressure by invasive species that have resulted in crop yield losses and damaged productive natural ecosystems.356,357 Increases in the frequency of heavy rain events358 and lengthening of dry spells between rain events at some locations in the region359,360,361 make water resources unpredictable. Hurricanes and tropical storm winds, as well as increasing accumulated rainfall in coastal areas, pose unique threats to agriculture.92,362 For example, following Hurricane Florence, swine feces markers were detected in surface waters in North Carolina, suggesting that management practices should be examined in areas at risk of increased extreme precipitation.363 Rising sea levels have increased saltwater intrusion in coastal aquifers, reducing the extent of available forests and farmland130,131 and threatening seafood harvesting in estuaries by altering the salinity and turbidity in freshwater streams and marine nurseries.364 Extreme weather and coastal stressors have also disrupted food distribution by closing ports and highways,365,366,367 reduced the catch of fish, and diminished crop production.140

Disproportionate Impacts on Under-Resourced Communities

Climate stressors such as drought have a disproportionate impact on small-scale, Black, Indigenous, and economically disadvantaged farmers, who are more concentrated in the Southeast compared to other NCA regions (Figure 22.18).368,369,370 These groups are under-resourced, making adaptation to climate change more difficult.371 Knowledge gaps in best practices for small-farm management complicate information-sharing among communities across the region. Access to broadband in rural areas may limit producersâ ability to monitor their fields and make appropriate management decisions.372,373 Small-farm owners also have limited financial resources, which means they have less ability to invest in necessary farm equipment, insurance, and other risk-reduction methods such as irrigation that could mitigate climate stress and reduce farmland value losses.374,375 Small-scale farmers and those with limited resources may find targeted USDA programs as well as innovative techniques such as organic farming and agroforestry to be well-suited to use on their smaller farms in the future.376,377

Competition for Resources

Southeastern agriculture and food systems are further stressed by land, water, and resource competition between urban and rural areas.378 Competition is highlighted by decades of lawsuits in the Southeast involving the appropriate distribution of water resources among municipal water users in large cities, agricultural producers using irrigation to protect against drought, and coastal fisheries that rely on balanced salinity levels to maintain the health of estuarine systems.379 Sprawl is expanding into farmland, reducing the land available for food production and increasing the area affected by urban heat islands.380 Similarly, native forests have been developed or replaced by commercial forests, which may lack biodiversity and ecosystem resilience.381

Regional Dependencies

Climate stressors in other regions can have cascading effects on the Southeast and in turn the entire United States. For example, sea level rise is expected to hinder the operation of ports where food, other agricultural products, and other needed supplies are imported and exported (KM 22.3). Additionally, low and high flows from droughts and floods may hamper the movement of food and agricultural products within and through the region, especially in highly urban and rural areas.382,383 Climate extremes can also reduce crop yields elsewhere and thus the availability of food products for the Southeast, potentially increasing stress on under-resourced populations through cost hikes and decreasing access to nutritious food.384,385

How Agriculture and Food Systems Are Adapting in the Southeast

Agricultural producers are using various techniques to respond to increased climate stress, which is expected to result in decreased crop yields in many parts of the Southeast (Figure 22.19).300 Precision agriculture can minimize water use through the timely and appropriate irrigation of crops based on growth stage and soil moisture.386 The use of cover crops to preserve soil moisture and nutrients reduces the impacts of soil erosion and the leaching of nitrate into waterways and coastal estuaries, as well as the need for expensive inputs of fertilizer and irrigation water (Ch. 11).387,388,389 Other innovative agricultural techniques such as organic farming, advanced grazing management, silvopasture, agroforestry, and other agroecological systems (Box 22.3) also show promise for adapting to future climate changes in the region through a reduction in emissions of greenhouse gases and increased carbon sequestration in the soil and vegetation.376 New crops such as olives and satsuma citrus have been introduced to some areas to take advantage of the shifting plant hardiness zones and favorable market value of the crops.390,391,392,393 Genetically modified organisms and new cultivars of perennial crops can contribute to reduced emissions of greenhouse gases through reductions in fieldwork and may reduce the need for inputs such as pesticides, as well as provide additional resilience to expected increases in temperature and drought that may threaten long-term yields.394,395,396 A longer growing season also allows some producers to grow two crops in a year instead of one, reducing the likelihood of a weather catastrophe destroying a yearâs harvest in a single event.397