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Environment Magazine September/October 2008


September 2007

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The U.S. Hurricane Coasts: Increasingly Vulnerable?

The devastating images of New Orleans and the Mississippi Gulf Coast in the aftermath of Hurricane Katrina linger in the American consciousness, fueled by mass media images of the death and destruction. Two years post-event, recovery in many places along the affected Gulf Coast is progressing at a snail’s pace. Displaced residents, especially the poor and disenfranchised, are living in temporary housing inside and outside the region; many with little hope of returning. While Hurricane Katrina was catastrophic, a similarly devastating hurricane could strike anywhere along the Gulf Coast or the Atlantic seaboard. As another hurricane season unfolds, a critical question to address is why the nation’s coasts are becoming more vulnerable.

This vulnerability arises from the interactions between the human-environment systems, where physical processes play out on a landscape of increasingly dense human development. Alterations in the physical system enhance the effects of tropical storms or hurricanes, while development creates greater economic exposure and likely losses from hazards regardless of their cause (earthquakes, hurricanes, and floods). While all coastal areas are vulnerable to varying degrees, it is along the nation’s hurricane coasts where the increasing vulnerability is most apparent.

U.S. Settlement and Vulnerability

The settlement history of the United States can be characterized as a series of great migrations. The first was the pioneer settlements and westward expansion facilitated by federal incentive programs such as the Homestead Act (1862) and the Railroad Acts (1850s–1860s). Originally designed to encourage settlement for economic and political reasons especially in the Great Plains, these programs transferred government-owned land to private ownership at little or no cost.

The second migration wave was the transformation of the country from an agrarian society to an industrialized one, with a mass exodus from the farms to the fledgling cities and factories during the Great Depression. The expansion of agriculture in the Midwest and Great Plains during the late nineteenth and early twentieth centuries led to soil erosion, deforestation, and flooding resulting in unsustainable practices and severely depressed economic conditions in the Appalachian region of the Southeast. At the same time, several dry years, low farm prices, and wind erosion created the Dust Bowl,1 forcing thousands off the land in one of largest migrations in the nation’s history as destitute farmers from the Southern Plains moved westward to California. The establishment of the Tennessee Valley Authority, ostensibly designed to bring electricity to the Appalachian region, was part of the New Deal to help stimulate industrial development in the region.

The third migration was the intensification of urban settlements and the growth of U.S. cities. Industry, jobs, and thus residents were increasingly concentrating in higher density urban environments, especially along the coast. Next, the affordability of the automobile, new housing construction to meet the needs of the post-war baby boom, and the completion of the interstate highway system provided the setting for the fourth wave of migration: the rapid suburbanization within these metropolitan areas. The metropolitan growth and suburban sprawl gobbled up available land within metropolitan areas and often created a pattern of development that was indistinguishable from one place to another such as in what are termed “megalopolises,” which are often used to describe the metropolitan regions from Boston to Washington, DC.

The fifth migration, as some argue, is now in progress.2 This is the re-vitalization of the older cores of the metropolitan areas, a process that began in the 1980s. Such re-urbanization, largely led by affluent younger professionals, aging empty-nesters, and immigrant populations, has already advanced in Boston, New York, Chicago, Los Angeles, and San Francisco/Oakland. This latest wave is changing many of the nation’s coastal cities where housing prices have soared; banking, insurance, and other financial services dominate; and the cultural amenities cater to the resident and tourist populations.

Population Growth

In October 2006, the U.S. population surpassed 300 million and is expected to reach 400 million by 2040.3 By the time the fifth migration has played out, it is expected that more than 60 percent of the population will be concentrated within 10 “mega-regions” of the country.4 Eight of these mega-regions are located in coastal states and within coastal counties: the Northeast (from Washington, DC, to Boston), the Piedmont (Charlotte/Raleigh and Atlanta), Florida (Tampa/Orlando and Miami), the Texas Triangle (Houston, San Antonio/Austin, and Dallas-Ft. Worth), the Great Lakes (Cleveland, Cincinnati, Detroit, and Chicago/Milwaukee), Cascadia (Seattle and Portland), Northern California (San Francisco Bay Area), and Southern California. The Front Range (Denver) and the Sun Corridor (Phoenix/Tucson) are the only two non-coastal regions. In addition to hosting a large and growing population, these mega-regions are home to the country’s busiest air- and seaports and leading office and high-tech markets. They produce more than 70 percent of the U.S. gross domestic product.

To accommodate the next 100 million people, the nation will need to add 70 million housing units (at a rate similar to recent years of 2 million per year) to the current stock of 125 million5—40 million will be new housing units on new residential parcels while the remaining 30 million will replace damaged or demolished units on existing property. To accommodate these burgeoning mega-economies, it will be necessary to construct 100 billion square feet of nonresidential space—30 billion of which will be new square footage and 70 billion of which rebuilt or replaced.6 Much of this growth will be in coastal areas.

The Lure of the Coasts

Figure 1Depending on the definition of “coastal”—and there is considerable debate on what this refers to—anywhere from 18 percent to 53 percent of Americans live in designated coastal areas.7 There has been an 11 percent change in coastal population between 1990 and 2000, and, from 2000 to 2005, coastal populations have increased on the order of 1 percent per year. Four counties in Florida (Citrus, Hernando, Collier, and Flagler) experienced more than a 500 percent growth in population since 1970, and Flagler has seen more than a 1,000 percent increase during this time period (see Figure 1).

In addition to historic population patterns along the coasts, increasing settlement was driven by coastal-dependent economic activity such as shipping, marine fishing, and oil and gas extraction.8 At the same time, recreation demand and accessibility by rail led to the development of the first coastal leisure cities: Atlantic City, New Jersey, and Ocean City, Maryland. The deluge of recreational demand for beaches and coastal living in the post-war era resulted in the gentrification of the coast largely due to increasing wealth and leisure time, a process that began in the 1950s. Demand for second homes—vacation or retirement—fueled development in the coastal counties and, with improvements in access (such as interstate highways and bridges to barrier islands) and infrastructure (water, sewers, and electrical power), contributed to the current coastal crisis by exposing many more people and infrastructure to natural disasters than ever before.9

Today coastal counties contribute $5.6 trillion to the national economy (45 percent of the U.S. total) with more than 54 million jobs. In the leisure sector alone, coastal counties contribute $340 billion to the national economy and more than 10 million jobs.10

Who is migrating to the coast and how have these demographics changed? According to one recent commentary,11 there is a domestic outflow of residents from the coastal megalopolises, but those population losses are tempered by an immigrant population inflow. The coastal megalopolises are losing their middle class, quickly becoming economically segregated with a large affluent population at one extreme, and an equally large immigrant, low-wage earning population at the other. While there is no net loss in population, the characteristics of that population have drastically changed, and so too has their vulnerability to hazards.

Migration to the Hurricane Coasts

While overall migration to the coast is a concern, it is the migration to the hurricane coasts that is the most worrisome. The population characteristics of the hurricane coasts (Gulf of Mexico and Southern Atlantic) have changed—in population size as well as in the characteristics of the new residents. The hurricane coastal counties have increased the percentage of their population that is elderly as well as the number of female-headed households (see Table 1). The elderly, mostly located in Florida in 1970, have increased in percentages in a demographic pattern that now spans north (along the Carolinas coast) and west (along the northern Gulf Coast) in 2000. While few changes in the racial composition of the hurricane coasts occurred, there were significant changes in ethnicity since 1970, with the influx of Hispanics, not only along the South Texas coast but throughout the Gulf and Atlantic coastal counties as well. There was a dramatic decrease in the percentage of children in hurricane coastal counties from 1970 to 2000 and a decline in the percentage of people living in poverty.Table 1Table 1

The percentage of owner-occupied housing increased slightly (70 to 75 percent). More significantly, the percentage growth in manufactured homes increased from 8 percent of the housing stock in 1970 to 23 percent in 2000. Interestingly, the rental vacancy rate has nearly tripled from 1970 to 2000, suggesting an increase in the number of seasonal rental properties as well. While the median contract rent remained level, the median value of owner-occupied housing nearly doubled (see Table 1). In other words, the population along the hurricane coasts is aging and becoming more Hispanic, more people are living in mobile homes (the only affordable housing), and the median value of owner-occupied housing has doubled, all within the past 30 years.

Figure 2
There is a geography to these changes, and it translates into a regional pattern of hazardousness along the hurricane coasts. The transformation from rural, low density to higher density suburban and urban places not only increased the population, but also significantly altered the landscape and the built environment in coastal counties. The rapid suburbanization of the Southeast and Gulf Coast shorelines is illustrated by the changes in the development of residential units. With the exception of the Texas and Louisiana coasts, residential units have increased by more than 100 percent throughout the northern and eastern Gulf of Mexico counties and from Florida to North Carolina along the Atlantic Coast. Much of this increase is attributable to the increase in mobile homes and in seasonal housing. In 1970, mobile homes were more than 30 percent of the housing stock in only one coastal county, Plaquemines, Louisiana, but by 2000 that spatial pattern was dramatically altered, spreading throughout central Florida and its west coast and along the Carolinas coast (see Figure 2).

Seasonal housing, which is only intended for occupancy during certain times of the year such as summer, is generally found in resort areas along the hurricane coasts. In 1970, there was only one county (Brunswick County, North Carolina) with a seasonal vacancy rate higher than 30 percent, but the growth in seasonal properties was explosive, and by 2000, most of the hurricane coast had seasonal vacancy rates exceeding 30 percent. These general social descriptors apply at the aggregate county level, but there is considerable geographic variability within each county; for example, the most affluent might live right on the shoreline in beachfront property, but further inland there is a more diverse population (racially and economically).

More than Just Population Numbers

The increasing number and density of people and structures in the coastal zone is important, as is the demographic structure of communities. Social vulnerability identifies those characteristics of the population that influence the social burdens of risk. It helps us understand why some communities are more susceptible to the impacts of a disaster (not necessarily in dollar losses, but in human losses) as well as their ability to recover from them.12 The Social Vulnerability Index (SoVI), developed in 2003, illustrates the geographic dimensions of social vulnerability. The index is based on U.S. Census data to maintain geographic comparability. Derived from nearly 40 years of social science research on disasters, the index is a synthesis of those demographic characteristics of communities that either increase or decrease their vulnerability to disasters.13 For example, age is a contributor to increasing vulnerability—the elderly because of their limited mobility and likely health care access needs; children because of their dependency on adults for food, shelter, and comfort. Socioeconomic status influences the ability to absorb losses and recover from them. Wealthier communities can rely on individual safety nets such as insurance to cope with disaster losses, but poor communities lack such capacity. Race and ethnicity provide measures of language and cultural barriers that influence trust of warning information or access to post-disaster recovery resources. When SoVI is applied to coastal counties, it reveals dissimilarities in potential impacts and foreshadows disparities in the post-disaster recovery.14

The distinction between total population counts and social vulnerability is illustrated in Figure 3. Among the most socially vulnerable counties along the Gulf Coast are Orleans Parish (New Orleans), Louisiana; Citrus and Hernando counties (respectively 70 and 45 miles north of Tampa) in Florida; and Cameron (Brownsville) and Willacy (just north of Cameron) counties in Texas. For each, different factors drive the vulnerability. For example, in Orleans Parish it is race (African American) and gender (women); in Citrus and Hernando Counties, Florida, it is age (the elderly) and ethnicity (Hispanic); while in Cameron and Willacy, Texas, it is socioeconomic status (poverty), age (young), and ethnicity (Hispanic). While the underlying factors are different, each contributes to the overall social vulnerability of these counties, which in turn influences their ability to prepare for, respond to, and recover from coastal disasters.Figure 3

Increasing Dangers

There is considerable debate in the climate community on whether the frequency of tropical storms and hurricanes has increased over time and, if so, whether this is linked to anthropogenic global warming15 or improved monitoring.16 What is less controversial is the presence of global warming and its regional effects. The Intergovernmental Panel on Climate Change report17 suggests that the United States will see more temperature extremes in the next century and a likely intensification of tropical cyclones with higher peak winds and heavy precipitation. An overall increase in severe weather is likely, resulting in more intense and prolonged heat, drought, and flood events, in addition to tropical cyclones.

Figure 4A quick glance at U.S. hurricane tracks from 1960 to 2005 illustrates just how vulnerable our coastal counties are to these physical processes (see Figure 4). When compared to the number of presidential disaster declarations given for tropical storm/hurricane events (including wind, coastal flooding, and inland flooding), it is clear that the impacts of tropical cyclones extend far beyond coastal counties. What is also apparent is the geographic concentration of the physical vulnerability along the northern Gulf Coast, Florida (both Gulf and Atlantic Coasts), and the Carolinas.

The vulnerability of the coastlines themselves is equally a concern. With a mean sea level rise of 0.17 meters during the twentieth century,18 the coasts will lose valuable wetlands and mangroves—natural buffers that protect the shoreline from storms. At the same time, the shoreline landmass will be lost due to incipient erosion as well as erosion caused by tropical and extra-tropical storms. Increased coastal flooding is a near certainty in the future.19 The increasing physical vulnerability of the coast is occurring at the same time as the increasing pressures for development in these same environments, setting the stage for disaster.

Disaster Losses

Hazard losses are increasing in the United States and, at the same time, there have been more catastrophic events. For example, from 1960 to 2005, there was a steady upward trend culminating in 2005, the most costly year for disaster losses in the nation’s history with more than $100 billion. Weather-related hazards are the most costly (representing 86 percent of the total losses for the past 45 years). Interestingly, non-hurricane losses (earthquakes, severe weather, and drought) outstrip hurricane losses in all years, with the exception of 2005. This pattern is reflective of the role of smaller, more frequent hazards such as flooding and severe weather including tornadoes, which occur annually and result in a cumulative pattern of losses.20 The less frequent, more catastrophic events such as earthquakes and major hurricanes show up in the spikes of the curve—1980 (Mt. St. Helens volcanic eruption), 1989 (Hurricane Hugo, which struck Puerto Rico and the Carolinas; Hurricane Iniki, which struck Hawaii; and the Loma Prieta earthquake in San Francisco), 1993 (Mississippi flooding), 1994 (Northridge earthquake in southern California), 2004 (Florida hurricanes), and hurricanes Katrina, Rita, and Wilma in 2005. These billion-dollar events illustrate the increasing frequency of singular events yielding large damages throughout the nation, not just in coastal areas.21

Figure 5For coastal areas, the geographic distribution of losses is instructive (see Figure 5). For example, during the past 15 years, the highest-loss regions include the northern Gulf Coast counties from Houston to the Florida Panhandle, Southern Florida (east and west coasts), Southern California, the San Francisco Bay Area, and the Seattle metropolitan area. The causal mechanism is different between the regions (see Figure 6). For the Pacific coast, the primary cause of hazard losses was geophysical events, especially earthquakes and landslides. For the Great Lakes, severe weather contributed to the loss of distribution. Along the Atlantic coast, hurricanes and tropical storms caused more than 69 percent of all the hazard losses, followed by flooding and severe weather. The causal pattern for the Gulf Coast was different and included a combination of hurricane and tropical storms coupled with coastal hazards (defined as coastal flooding, storm surge inundation, and erosion). It is noteworthy that on the other three coasts, coastal hazards represented less than 1 percent of the losses during the past 15  years.Figure 6

What is contributing to this trend toward increasing losses in our coastal areas? Arguably, a significant portion of the increasing cost of coastal disasters has been caused by the location and density of coastal development patterns and the aging building stock and infrastructure. Despite recent periods of intense tropical storms and hurricanes, the escalating costs of coastal disasters are a function of human choices, not necessarily increases in the forces of nature.22 Local city councils, planning commissions, and planning and building permitting departments are at the front lines of the increasing coastal hazardousness. These bodies are responsible for allowing new development and deciding whether to invest in replacing and upgrading aging buildings and infrastructure. But they are also under siege on a number of fronts and, in many instances, lack the adequate tools and resources to resist. Development pressure is not just a political condition; it is a financial reality. Local jurisdictions are increasingly tax-starved as state and federal allocations have been cut back. Cities compete with neighboring cities to attract the “big-box retailers” and other major sales tax revenue generators into their jurisdictional boundaries. When local budgets are tight, personnel are cut and adequate staff may be lacking to review applications and enforce regulations. Similarly, if public infrastructure maintenance is deferred year-in and year-out, the consequences can be devastating.

Many coastal states have led the nation in land-use policymaking. Florida, Oregon, California, and Maryland are among the leaders. But strong state-level mandates do not necessarily translate into strong local controls. A recent study of the implementation of “smart growth” land use regulations in Maryland underscore the need of local jurisdictions for state support as well as regional implementation for local land use regulations to be effective.23

Similar challenges persist for local building code implementation. Ninety percent of the U.S. population resides in local jurisdictions that enforce codes that establish standards for construction, plumbing, mechanical, and electrical systems.24 But local resistance also arises as local jurisdictions have higher inspection and enforcement costs, and more stringent codes often result in higher building costs. In November 2005, soon after the devastating impacts of hurricanes Katrina and Rita, the state of Louisiana adopted more stringent statewide building standards. With two years of implementation experience, state lawmakers are being pressured to lessen the burden on non-coastal regions of the state.25 Unless local land use and construction practices are strengthened, the hazardousness of U.S. coastal communities and the potential for future losses will likely increase.

Hurricanes as a Suburban Experience

No landfalling hurricane has hit a major U.S. city directly, but some have come close. In 1900, Galveston was destroyed and more than 8,000 people lost their lives, the worst natural disaster in U.S. history in terms of fatalities. The Great Miami hurricane of 1926 resulted in 373 fatalities and tens of thousands of people left homeless. In 1992, Hurricane Andrew made landfall just south of Miami (near Homestead), while in 1989, Hurricane Hugo struck just north of Charleston, South Carolina. More often than not, the direct impact of hurricanes is felt in the suburban and rural areas of the coast.

Hurricane preparedness in the United States is based on a suburban context—lower population densities, access to private automobiles, more wealth—not an urban context. The predominant form of precautionary measures for an impending hurricane is evacuation, and the implementation and management of evacuations makes two important assumptions: residents have private transportation that they can use to get out of harm’s way, and residents are willing and able to leave their homes when advised to do so. As was demonstrated in Hurricane Katrina, nearly 26 percent of New Orleans’s central city residents did not have access to private vehicles. In other large coastal cities, this pattern is repeated. In New York City, 48 percent (or 3.8 million) of the residents do not have access to private automobiles. In Washington, DC, the percentage is 32 percent (183,000); in Baltimore, it is 32 percent (205,000); and in the greater Miami area, it is 10 percent, or nearly 220,000 residents.26

The second assumption is equally questionable. The evacuation research literature tells us that individuals are increasingly risk savvy and make decisions to evacuate based on several sources of information (such as prior experience with hurricanes, advice from family and friends, and their own assessment of the risk)—not just the official advisories. This individual decisionmaking leads to two outcomes, both of which complicate evacuation management. The first outcome is the response where residents do not heed the warning and prefer to remain at home and ride out the storm, sometimes successfully, sometimes not. The second outcome is the response where many more people evacuate than need to, creating what is termed an “evacuation shadow.” The evacuation of the Texas coast during Hurricane Rita is a good example of this evacuation shadow phenomenon. In hurricanes, evacuation shadows normally range from 10 percent to 20 percent additional evacuees. In the case of Hurricane Rita in Texas, more than 2.4 million people actually evacuated from the Greater Houston-Galveston area (prompted by the outcome of Hurricane Katrina a few weeks earlier), approximately 62 percent of whom were not in a mandatory evacuation zone.27 Instead of a smooth traffic flow inland from the coastal areas, interstates and highways were jammed with cars and people ran out of gas, food, and water, stranding many evacuees along the side of the road. Others became frustrated with the traffic and returned home, preferring to ride out the storm in their houses rather than in their vehicles. Given the influx of people to coastal areas, many of them without hurricane experience, we should anticipate larger evacuation shadows in the future.

Future Surges and Urban Vulnerability

The urban catastrophe that befell New Orleans in 2005 provides many lessons for the increasingly urban nature of coastal communities. For the first century of its settlement, New Orleans’s urban footprint was constrained by surrounding swamp lands and largely concentrated on the naturally elevated ridges formed by historic flooding of the Mississippi River. As engineering technology improved, swamplands were drained and new developable lands were protected by an intricate system of levees, floodwalls, pumping stations, and drainage canals constructed over decades by the U.S. Army Corps of Engineers and the city’s sewerage and water board. The false sense of security provided by the extensive engineered system was not just a local perception. Once the National Flood Insurance Program (NFIP) was created (and the City of New Orleans elected to participate), even the NFIP flood insurance rate maps did not fully account for the potential catastrophic failure of the levee system. It was therefore possible to build NFIP-compliant homes (eligible for flood insurance) in low-lying areas of the city on slab foundations, significantly increasing the city’s vulnerability if the unthinkable did indeed happen.

A recent study by the Center for Bioenvironmental Research (CBR) estimates that in 1919, approximately 90 percent of New Orleans’s 339,000 residents lived above sea level.28 By 1960, when the city’s population peaked at 627,535, 48 percent (or 306,000) of New Orleanians lived above sea level. During these decades, as the city’s population boomed, growth spread into the low-lying areas mostly west of the Industrial Canal, which was one of the canals that failed in Katrina’s wake.

After 1960, New Orleans’s population began a slow downward decline to 484,674 in 2000. Yet, during those 40 years, CBR’s study shows that many of the city’s residents migrated out of the city and from higher-elevation areas of the city to low-lying lands in areas in the west end of the city, beyond the Industrial Canal. By 2000, only 185,000 New Orleanians lived above sea level. The city’s population density also dropped dramatically between 1960 and 2000.29 In 1960, 627,535 people lived mostly within 36.8 square miles of developed land, equating to 17,053 people per square mile. By 2000, the city’s footprint of occupied and developed land had expanded to 66.7 square miles, but the population density had declined to 7,266 per square mile.

The 40 years of population decline and simultaneous sprawl also had a severe effect on city coffers and the quality of local services. Local budgetary challenges resulted in facilities and infrastructure maintenance cuts and years of neglect. But the city was showing signs of recovery in the five years prior to Katrina. From fiscal year 2001 through 2004, the city had increasing revenue that was sufficient to pay for the general fund expenses and its annual debt service of nearly $39 million.30 With a stronger balance sheet, the city sought voter approval, in November 2004, for its largest-ever referendum of $260 million in general obligation bonds to improve, upgrade, and expand city infrastructure and facilities, and voters agreed.31 Just prior to Katrina, the city was preparing to sell the bond issuance to take advantage of its improved Better Business Bureau investment grade rating. According to capital improvement plans, the city planned to use more than half of the proceeds to repave and repair portions of the 1,600 miles of streets and also to upgrade many of its more than 400 public buildings, including police, fire, and judicial facilities.32

When Katrina struck on 29 August 2005, floodwaters inundated more than 80 percent of the city’s land area at heights well above NFIP’s base flood elevations. More than 90 percent of the city’s estimated 455,000 residents were displaced, almost 80 percent of the city’s buildings sustained some damage, and nearly half of all the habitable units were either damaged or destroyed.33 To offset the greater than 50 percent reduction in sales and property tax receipts, as well as anticipated declines in other revenue sources, the city had to implement drastic budget cuts, including a 50 percent reduction in administrative workforce (excluding public safety positions); more than 3,000 city employees were furloughed.34 Given the future financial uncertainties, the city’s bond rating was also downgraded to junk bond status, and the city was no longer able to sell the voter-approved bonds.35

Now, as the two-year anniversary of Hurricane Katrina’s devastating landfall is fast approaching, little more than half of New Orleans’ population has returned.36 While recovery of population following other modern disasters has been relatively quick for most cities, none had the widespread destruction or degree of forced evacuation and long-term displacement as New Orleans. The population in the higher-elevation parts of the city has come back and in some neighborhoods is even higher than pre-Katrina levels. In the flooded areas, repopulation has been fairly proportionate to the depth of the water and the ability of the residents to afford alternative housing and repair the damage to their homes.

Infrastructure and public facilities are still in disrepair, basic community services are still patchy, and the city is still struggling to identify the money to finance essential services and costly facility and infrastructure repairs. But the city’s planning commission has adopted a strategic recovery framework that works to balance the city’s recovery investments in facility and infrastructure repairs with the two key risks that could undermine them: the pace of repopulation and the risk of future flooding.37 City agencies, including the newly formed Office of Recovery Management, are also still negotiating with the Federal Emergency Management Agency and state counterparts to fund damage to public facilities and infrastructure, with the hope that good fiscal management will result in upgrades to the city’s investment rating.

Retreat from the Coast

It is clear that New Orleans will be rebuilt, but it is not yet clear what that future city is likely to look like. The future New Orleans will have a smaller footprint than before, and significant demographic and population shifts are likely. While New Orleans is the obvious example, we need to be mindful that catastrophes can strike at any time or any place. With the increasing exposure of the coasts, including the hurricane coasts, and the escalating losses from common (erosion) and extreme events (major hurricanes and earthquakes), it is time to think about a retreat from the coast. While living along the coast is idyllic, it does have its risks. The risk burdens are not proportionally shared by those who benefit from coastal living. Rather, the risks are shared among all of us through pooled insurance premiums, federal disaster relief, and federal subsidy programs, creating a situation where the few and privileged do not pay the true cost of their locational choices, especially along the hurricane coasts. The implementation of structural mitigation measures such as seawalls, groins, or sand replenishment are short-term stop-gap measures and will not significantly reduce the impact of coastal storms on local communities. A more durable solution is required.

Understanding these risks and improving the sustainability of coastal communities should be a local priority, backed by a national commitment for strengthening disaster resilience before the disaster occurs, not afterward. This will require changes in policy and practice at all levels of government and in all sectors. The transition to a sustainable coastal future will not be easy as there are many special interests, entrenched economic conflicts, and social inequalities that permeate the coast. But, with threats of sea level rise, increasing storm intensity, and higher disaster losses, collective action must be taken now if we want to safeguard these important environmental, cultural, and economic regions of the country. The prescription and path forward is already laid out.38 It just requires the public initiative and political will to do it. The time has come to seriously consider a retreat from the coast and the national implementation of coastal land use policies and their enforcement as a means for reducing the hazard vulnerability along the hurricane coasts.

Susan L. Cutter is a Carolina Distinguished Professor of Geography and director of the Hazards & Vulnerability Research Institute at the University of South Carolina. Laurie A. Johnson is an urban planner in San Francisco and disaster recovery specialist and technical leader on the Unified New Orleans Plan project. Christina Finch is the manager of the Hazards Research Lab at the University of South Carolina and worked for the Federal Emergency Management Agency as a disaster assistance employee in response to the 2004 Florida hurricanes and in Mississippi in 2005 for Hurricane Katrina. Melissa Berry is a graduate student in the Department of Geography at the University of South Carolina working on GIS applications to hazards analysis and management. The ideas and data in this paper were presented by the authors at the Natural Disasters Roundtable on 28 March 2007, “Protecting Lives and Property at Our Coastlines,” at the National Research Council/National Academies of Sciences Keck Center in Washington, DC.


1. D. E. Worster, Dust Bowl: The Southern Plains in the 1930s (Oxford: Oxford University Press, 1979).
2. R. Fishman, “The Fifth Migration,” Journal of the American Planning Association 71, no. 4 (2005): 357–66.
3. A. C. Nelson and R. E. Lang, “The Next 100 Million,” Planning 73, no. 1 (2007): 4–6.
4. A. C. Nelson and R. E. Lang, “The Rise of the Megapolitans,” Planning 73, no. 1 (2007): 7–12.
5. Nelson and Lang, note 3 above.
6. Nelson and Lang, note 4 above.
7. U.S. Census, Statistical Abstract of the U.S. 2005, Table 29, "Population in coastal counties: 1960–2005."  Coastal counties as defined by National Oceanic and Atmospheric Administration (NOAA) cover 673 counties with at least 15 percent of their land area either in a coastal watershed or in a coastal cataloging unit. This applies to the Atlantic, Pacific, and Gulf coasts and the Great Lakes region. A different definition of coastal includes those people living within 100 miles of the coast. Using this definition, 59 percent of the U.S. population is defined as “coastal.” See M. E. Hodgson, “How Many People Live Near the ‘Coast’? as a Measure of Risk,” paper presented at the Association of American Geographers annual meetings, San Francisco, CA, 17–21 April 2007.
8. The H. John Heinz III Center for Science, Economics and the Environment (the Heinz Center), Human Links to Coastal Disasters (Washington, DC: The Heinz Center, 2002).
9. C. Dean, Against the Tide: The Battle for America’s Beaches (New York: Columbia University Press, 1999).
10. J. T. Kildow, “Our Economy at Risk: The Costs of Living on the Edge,” PowerPoint presentation at the Natural Disasters Roundtable Workshop, Protecting Lives and Property at Our Coastlines: A Disaster Roundtable Workshop of the National Academies of Science, Washington DC, 28 March 2007; also see statistics available from National Ocean Economics Program (NOEP), Coastal Economy Data,  (accessed 21 May 2007).
11. M. Barone, “The Realignment of America,” The Wall Street Journal, 8 May 2007.
12. See S. L. Cutter, B. Boruff, and W. L. Shirley, “Social Vulnerability to Environmental Hazards,” Social Science Quarterly 84, no. 1 (2003): 242–61, for the original formulation. For the most current Social Vulnerability Index (SoVI) based on 2000 Census data, see University of South Carolina Hazards & Vulnerability Research Institute, Social Vulnerability Index (SoVI) for the United States.
13. Ibid.
14. For example, in examining the coastal erosion hazard, there were regional differences in vulnerability. Along the Atlantic and Pacific coasts, physical factors were more dominant, while in the Gulf Coast counties, social characteristics were slightly more important in explaining the variation in vulnerability. See B. J. Boruff, C. Emrich, and S. L. Cutter, “Hazard Vulnerability of U.S. Coastal Counties,” Journal of Coastal Research 21, no. 5 (2005): 932–42. In the aftermath of Hurricane Katrina, a historical analysis of social vulnerability among the affected counties in Louisiana, Mississippi, and Alabama showed little change in the relative vulnerability of Orleans Parish. Not only do the residents have less ability to cope with major disasters than residents of other parishes, the historical analysis suggests that they had less ability to recover in 2000 than they did in 1960. See S. L. Cutter and C. T. Emrich, “Moral Hazard, Social Catastrophe: The Changing Face of Vulnerability along the Hurricane Coasts,” Annals, American Academy of Political and Social Science 604, no. 1 (2006): 102–12.
15. M. Mann and K. Emanuel, “Atlantic Hurricane Trends Linked to Climate Change,” Eos, Transactions, American Geophysical Union 87, no. 24 (1 May 2006): 233, 238, and 241; Intergovernmental Panel on Climate Change (IPCC), Working Group 1, The Physical Basis of Climate Change. Assessment Report 4, Final Report, 1 May 2007 (Geneva: Intergovernmental Panel on Climate Change, 2007) (accessed 22 May 2007); and IPCC Working Group 2, Climate Change 2007: Impacts, Adaptation and Vulnerability. Assessment Report 4, Summary for Policymakers, 13 April 2007 (Geneva: Intergovernmental Panel on Climate Change, 2007) (accessed 22 May 2007).
16. R. A. Pielke, Jr., C. W. Landsea, M. Mayfield, J. Laver, and R. Pasch, “Hurricanes and Global Warming,” Bulletin of he American Meteorological Society 86, no. 11 (2005): 1571–75; C. W. Landsea, B. A. Harper, K. Hoarau, and J. A. Knaff, “Can We Detect Trends in Extreme Tropical Cyclones?” Science 313, no. 5786 (28 July 2006): 452–55; and C. W. Landsea, “Counting Atlantic Tropical Cyclones Back to 1900,” Eos, Transactions American Geophysical Union 88, no. 18 (1 May 2007): 197–208.
17. IPCC Working Group 2, note 15 above.
18. IPCC Working Group 2, note 15 above.
19. R. J. Nicholls, “Coastal Flooding and Wetland Loss in the 21st Century: Changes Under the SRES Climate and Socio-Economic Scenarios,” Global Environmental Change 14, no. 1 (2004): 69–86.
20. S. L. Cutter and C. Emrich, “Are Natural Hazards and Disaster Losses in the U.S. Increasing?” EOS, Transactions, American Geophysical Union 86, no. 41 (11 October 2005): 381 and 388–89.
21. For more information on these singular events, See NOAA, Billion Dollar U.S. Weather Disasters (accessed 26 April 2007); and N. Lott, “Tracking Billion Dollar U.S. Weather Disasters,” Bulletin of the American Meteorological Society 87, no. 5 (2006): 557–59.
22. S. A. Changnon, R. A. Pielke, D. Changnon, R. T. Sylves, R. Pulwarty, “Human Factors Explain the Increased Losses from Weather and Climate Extremes,” Bulletin of the American Meteorological Society 81, no. 3 (2000): 437–42; and R. A Pielke and C. Landsea, “Normalized Hurricane Damages in the United States: 1925–1995,” Weather and Forecasting 13, no. 3 (1998): 621–31.
23. A. Downs, “Smart Growth: Why We Discuss It More than We Do It,” Journal of the American Planning Association 71, no. 4 (2005): 367–80.
24. R. J. Burby, D. Salveson, and M. Creed, “Encouraging Residential Rehabilitiation with Building Codes, New Jersey’s Experience,” Journal of the American Planning Association 72, no. 2 (2006): 183–96.
25. S. Fox, “Building Codes: Will the Benefits of the New Statewide Building Codes Outweigh the Cost?” Greater Baton Rouge Business Report, 27 March 2007.
26. S. Raphael and A. Berube, “Socioeconomic Differences in Household Automobile Ownership Rates: Implications for Evacuation Policy,” paper presented at the Berkeley Symposium on Real Estate, Catastrophic Risk, and Public Policy, Berkeley, California, 23 March 2006.
27. M. K. Lindell and C. S. Prater, “Critical Behavioral Assumptions in Evacuation Time Estimate Analysis for Private Vehicles: Examples from Hurricane Research and Planning,” Journal of Urban Planning and Development 133, no. 1 (March 2007): 18–29.
28. R. Campanella, Above-Sea-Level New Orleans: The Residential Capacity of Orleans Parish’s Higher Ground (New Orleans: Center for Bioenvironmental Research at Tulane and Xavier Universities, 2007).
29. Ibid.
30. Unified New Orleans Plan, Final Draft, Citywide Strategic Recovery and Rebuilding Plan, Appendix E: Preliminary Citywide Financial Assessment, April 2007 (accessed 27 April 2007).
31. D. Robert, “Junk Bond Rating Prevents N.O. from Borrowing Recovery Cash,” New Orleans City Business, 11 December 2006.
32. Unified New Orleans Plan, note 30 above.
33. R. W. Kates, C. E. Colten, S. Laska, and S. P. Leatherman, “Reconstruction in New Orleans after Hurricane Katrina: A Research Perspective,” Proceedings, National Academy of Sciences 103, no. 40 (2006): 14653–60.
34. Unified New Orleans Plan, note 30 above.
35. Robert, note 31 above.
36. Unified New Orleans Plan, Final Draft, Citywide Strategic Recovery and Rebuilding Plan, April 2007, (accessed 27 April 2007).
37. Ibid.
38. The Heinz Center, see note 8 above; and U.S. Commission on Ocean Policy, An Ocean Blueprint for the 21st Century (accessed 27 April 2007). See Chapter 10 of the report, “Guarding People and Property Against Natural Hazards.”

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