COASTAL HAZARDS Too Many People Living Too Close to the Edge of a Rising Sea

COASTAL HAZARDS Too Many People Living Too Close To The Edge Of A Rising Sea

A Growing Challenge For The 21st Century

This Report Is Part Of The Ocean On The Edge Series Produced By The Aquarium Of The Pacific As Products Of Its National Conference—Ocean On The Edge: Top Ocean Issues, May 2009 2 COASTAL HAZARDS Ocean on the Edge: Top Ocean Issues Making Ocean Issues Come Alive for the Public

The conference brought together leading marine scientists and engineers, policy-makers, film-makers, exhibit designers, informal science educators, journalists and communicators to develop a portfolio of models for communicating major ocean issues to the public. This report is one of a series of reports from that conference. The reports include: Coastal Hazards, Marine Ecosystems and Fisheries, Pollution in the Ocean, and Critical Condition: Ocean Health and Human Health. There is also a series of briefer reports on film-making, kiosk messaging design, and communicating science to the public. All reports are available at www.aquariumofpacific.org

COASTAL HAZARDS 3 4 COASTAL HAZARDS Acknowledgements

Support for the “Ocean on the Edge Conference: Issues” held in May 2009, at Long Beach Top Ocean Issues” was provided by NOAA, Convention Center. Participants in the the National Science Foundation, Southern Coastal Hazards workshop session included: California Edison, SAVOR, the Long Beach Dr. Robert Dean, Dr. R. A. Dalrymple, Dr. Convention Center, and the Aquarium of the Conrad C. Lautenbacher, Jr., Dr. Jerry R. Pacific. Schubel, and Dana Swanson. Sandy Eslinger was the facilitator of the session. Leah Young We are grateful to the Conference’s National and Margaret Schubel were the rapporteurs. Advisory Panel that provided valuable guid- ance in selecting participants and in review- The report was reviewed by Dr. Orrin Pilkey, ing sections of this report. Members are listed William Sargent, Julie Thomas, Doug Harper, in Appendix A. and Adam Stein all of whom also provided text boxes to enhance the report. This report is based very loosely on the report, “Coastal Hazards” published by the National Academies in their Ocean Science Series which formed the starting point of discussion at the Aquarium of the Pacific’s Conference, “Ocean on the Edge: Top Ocean

COASTAL HAZARDS 5 National Advisory Panel

D. James Baker

Tom Bowman

John Byrne

Michael Connor

James Cortina

Joseph Cortina

Robert Dalrymple

Lynn Dierking

William Eichbaum

John Falk

Alan Friedman

Martha Grabowski

Mary Nichol

William Patzert

Shirley Pomponi

William Reeburgh

Jonathan Sharp

6 COASTAL HAZARDS Table of Contents

Introduction ...... 9 Setting the Stage ...... 11 Sea Level ...... 11 What’s Different? ...... 12 The Big Unknown ...... 13 Like Politics, All Sea Level Rise is Local ...... 13 Increasing Vulnerability to Risk ...... 15 The Higher the Sea, The Higher the Risk ...... 15 Areas at Greatest Risk ...... 16 Atolls: The Canaries in the Mine ...... 17 The Allure of the Coastal Zone ...... 18 Hurricanes and Other Coastal Storms: A Growing Threat ...... 21 Some Places and People are at Greater Risk Than Others ...... 24 How Will Global Climate Change Affect Hurricanes and Other Tropical Storms? ...... 24 Coastal Populations at Risk ...... 26 Adapting to a New Normal ...... 27 Policies to Nudge Us in the Right Direction ...... 27 Resilient Coastal Communities ...... 30 Inundation Maps ...... 31 The Roles of Science ...... 35 The Roles of Engineering ...... 36 Closing Observations ...... 38 Appendix A ...... 40 Recommended Readings ...... 40 Appendix B ...... 41 Conference Participants ...... 41

COASTAL HAZARDS 7 8 COASTAL HAZARDS Introduction

The Earth and the ocean are warming. Gla- In this brief document we explore sea level ciers and ice sheets are melting. The addi- rise and inundation—the causes and conse- tion of new water and the expansion of the quences, the prognosis for the future, and warming upper ocean are causing sea level what can be done to decrease vulnerability to rise—worldwide. This is nothing new. Sea and risk to make coastal communities more level has been rising since the end of the last resilient. We draw upon a large number of ice age, about 18,000 years ago. Throughout sources but two in particular: the NAS report, geologic time sea level has risen and fallen. It Coastal Hazards (2007) in the Ocean Sci- has been higher than today, and lower than ence Series; and the Proceedings from the today. The shoreline, and coastal ecosystems Sea Level Rise and Inundation Community including beaches, wetlands, mangrove for- Workshop (2010) sponsored by the National ests, and barrier islands have advanced and Oceanic and Atmospheric Administration retreated laterally with the rising and falling (NOAA) and the U.S. Geological Survey sea. For nearly all of human history, some (USGS) and facilitated by the Aquarium of 100,000-200,000 years, humans have moved the Pacific in December 2009.1 with the shoreline.

But something is different now. More than half of the 6.8 billion people worldwide live near the coast. Hundreds of millions live in low-lying coastal areas. We have built houses, hotels, condominiums, office buildings, stores, factories …entire communities, including large cities, along with the infrastructure—highways, railways, subways, water and wastewater treatment and distribution systems, and electric generating facilities— needed to support them, all at the edge of an increasingly restless sea.

1. Recommended readings are listed in Appendix A.

COASTAL HAZARDS 9 10 COASTAL HAZARDS Setting the Stage

Sea Level Sea level has been rising for the past 18,000- 20,000 years, since the end of the last ice age, but something is different now. Climate change is causing sea level to rise more rapidly and the number of people, the number and value of structures, and the number of natural environments at risk, are far greater now than at any time in human history.

Over the past century, sea level rose world- Source: Wikimedia Commons wide by about 7 inches. Over this century it may rise by 3 feet, 5 feet, or much more depending upon how much of the Greenland and Antarctic ice sheets melt.2 Both ice sheets are melting faster than scientists predicted just a few years ago. Even the lower bound of most sea level rise estimates will have catastrophic impacts on low-lying coastal areas of the world that are home to about 10% of the world’s population.

Sea level rise is driven by two processes associated with global warming—the expansion of the ocean as it warms and the addition of new water from melting of glaciers and continental ice sheets. Over the past few decades the contributions from each have been roughly the same. But that will probably Source: Wikimedia Commons

2. IPCC 2009

COASTAL HAZARDS 11 Beach Erosion: Esplanade Drive in Pacifica, California change well before the end of this century as by storms. Oceanic storms of all kinds— from 1997 to 1998. Dur- more melt water is added to the ocean. hurricanes, typhoons, Nor’easters, and ing the 1997 to 1998 El cyclones—produce greater damage when For every degree Fahrenheit the upper ocean Niño season, California’s superimposed upon a higher standing sea, warms, it expands between 0.5 foot and 1 coastlines were hit by both because of greater damage from waves foot. For every foot it rises vertically, the sea major beach erosion caus- and particularly from increased storm surges. advances laterally. The inundation ranges ing millions of dollars in There is growing scientific evidence that from very little where the coast is made up damage. global warming is increasing the intensity of steep vertical cliffs such as along parts of and probably the frequency of tropical NASA/Goddard Space flight Center the west coast of the U.S. to several thousand storms—hurricanes and typhoons. Scientific Visualization Studio. feet where the coast is low-lying and gently sloping such as along the Gulf and Southeast What’s Different? coasts of the U.S. To exacerbate the problem, Sea level has risen and fallen throughout geo- both the Gulf and Southeast regions are sink- logic history. Continental ice sheets waxed ing so the effective rise of sea level in these and waned throughout the most recent Gla- regions is greater than the global average.3 cial Epoch, the Pleistocene, which extended from 1.8 million years ago to about 18,000 The rising sea is invading low-lying coastal years ago. The rise and fall of the sea in lands, eroding coastal cliffs and beaches, response to the retreats and advances of the intensifying coastal flooding, and invading great ice sheets was part of nature’s rhythm, coastal groundwater supplies. The effects of and part of the early human experience. the inexorable rise of the sea is punctuated Humans first appeared on the evolutionary

3. You can find predictions of sea level rise for individual properties by going to http://www.floodsmart.gov and typing in your address.

12 COASTAL HAZARDS Source of data modified from CLIMAP isotopic data summarized in chart is from Ice Ages by John Embris and Katherine Imbrie, 1979.

stage between 100,000 and 200,000 years • If all of Greenland were to melt, global ago, and it took until about 200 years ago for sea level would rise 23 feet.4 the population to reach one billion. • The Western Antarctic Ice Sheet is the Since the end of the last ice age, sea level smaller of the two Antarctic Ice sheets, has been rising in response to the release of but is by far the more unstable and melt water from the retreating glaciers. It has could cause sea level to rise 16 feet by risen roughly 400 feet over that time with 2100 if it were to melt entirely. almost all of that coming before 8,000 years ago when the rate of rise averaged about 5.5 Once these ice sheets start to disintegrate, inches/decade. From 3,000 years ago until and they have, the process can proceed the beginning of the 19th century, the rate of rapidly with little warning. Unlike the rise sea level rise was only about 0.05 inches per associated with expansion from warming, the decade—one-tenth the rate over the previous disintegration of ice sheets and the addition 10,000 years. Over the past century, global of melt water to the ocean is non-linear. sea level rose about 7 inches. Within the past few decades the rate of rise has increased. Like Politics, All Sea Level Rise is Local The Big Unknown It is important to distinguish between world- The largest unknown in future sea level rise is wide changes in sea level, so-called eustatic the rate of melting of the ice sheets of Green- sea level, which affects the entire world land and Antarctica. They contain 75% of the ocean, and regional changes in sea level. The world’s fresh water. latter are relative to benchmarks on land. If the land is moving up or down because of

4. Herring, D. (2005) Time on the shelf. Earth Observatory. Retrieved October 29, 2009, from http://earthobser- vatory.nasa.gov/Features/TimeShelf/

COASTAL HAZARDS 13 geologic processes, that alters how people on arctic ice sheets. Science tells us that the rate land observe and experience the change in of rise will be more rapid than it has been in the level of the sea. For example, for people at least the past 3,000 years and that before living along the coast of the Gulf of Mexico, the end of this century, humans will have to the regional rise of sea level is much greater adapt to a higher sea. than the global-average because the entire Gulf coast is sinking. On the other hand, in some parts of Alaska sea level appears to be falling because the land is rising more rapidly than the sea. This is caused by rebound of the land associated with melting of glacial ice and decrease in weight on the land.

The direction of global sea level change for the foreseeable future is clear. It is up. There is less agreement on how much it will rise or how rapidly it will rise. The uncertainty comes primarily from the uncertainty of what will happen to the Greenland and Ant-

14 COASTAL HAZARDS Increasing Vulnerability To Risk

The Higher The Sea, The Higher The Risk Living near the coast always involves risk, and a higher sea makes it even riskier. The increased risk comes primarily from the chronic effects of inundation and accelerated coastal erosion. On the East and Gulf Coasts a primary concern is the episodic effects of storm surges superimposed upon a higher sea. Any significant increase in sea level can dramatically increase the destructive power of storm surges. On the West Coast, high tides and energetic waves are the driving force for inundation. A rise in sea level also increases the intrusion of salt water into coastal groundwater supplies.

Before humans, natural coastal environ- Kiribati, the Maldives, the Marshall Islands, Tokelau, and Tuvalu are all ments, such as wetlands, mangrove forests Island Nations threatened by the rising sea. and coral reefs, moved laterally to keep pace with the rising—or falling—sea. But humans have blocked the natural movements will increase as the Earth continues to warm. of beaches, dunes, salt marshes and other Many believe that in about 1995 we moved coastal environments with roads, bridges, into a different domain of intensity, and per- and an increasing number of structures—all haps frequency, of tropical storms. part of the infrastructure to accommodate a growing human population along the coast. This combination—a higher sea and in- So not only are human systems at risk from creased storm activity—increases the risk of a rising sea, but natural coastal ecosystems as living in the coastal zone and underscores well. Most have nowhere to go. the urgency of taking measures to assess coastal hazards and to reduce vulnerability. A growing number of oceanographers and Beginning with a rise of 2-3 feet, our nation climate scientists are convinced that the will be physically under siege. Long before intensity, and perhaps the frequency, of then, we will need to have executed plans on tropical storms, hurricanes and typhoons, how to respond.

COASTAL HAZARDS 15 The toll taken by the relentless rise of the sea Among the most vulnerable areas are low- over decades will be punctuated by storm lying delta regions such as those in Louisi- surge events during extreme storms like ana, Vietnam, Myanmar, Bangladesh, and Katrina that will devour large sections of the Egypt. Even at the lower bound of projected coast and everything in its path. Imagine sea level rise, the effects of a higher sea on Hurricane Katrina (August 2005) or the Indo- these areas will be profound. Tens of millions nesian tsunami (December 2004) if sea level of people worldwide will have to move to es- had been 3 feet higher. cape the advancing sea. Entire communities will have to be relocated to higher ground. Nature has built-in buffering capacity against Everything and everyone in the path of the major storms and storm surges. But in many rising sea is vulnerable. places we have removed or degraded nature’s protective buffers—wetlands, mangrove Ninety percent of Bangladesh is made up of forests, coral reefs, and offshore sand bars— floodplain and delta. The Meghna River is all of which dissipate the energy of the sea. formed by the confluence of Asia’s two larg- Many have been destroyed to make way for est rivers—the Ganges and the Brahmaputra. coastal development. In southern California In 1970 and 1991 storm surges caused by we drained and filled more than 95% of our tropical cyclones killed an estimated 500,000 wetlands. These actions have increased the and 140,000 Bangladesh residents respec- vulnerability of coastal communities world- tively. And floods in 1992 and 1998 flooded wide. more than half the country’s land area. It’s clear that a rising sea poses a daunting chal- Areas at Greatest Risk lenge for Bangladesh. It has been estimated The countries facing the most immediate that at least 15 million of the nation’s popu- challenges are island nations such as the lation will become environmental refugees Marshall Islands, the Maldives, Tuvalu, and before 2100. Kirabati; deltaic countries such as Egypt, the Netherlands, and Bangladesh; and countries Major parts of nations, such as Indonesia, with large, low-lying, heavily developed will be drowned. Some countries facing coastal plains such as the United States, Bra- submergence can retreat inland to higher zil, and China. ground, but others have no place to go.

Village of Shishmaref, Alaska before the storm (below left) and after the storm (below right). Images courtesy of Nome Nugget Newspaper.

16 COASTAL HAZARDS Atolls: The Canaries In The Mine Atolls are the circular islands of coral found in tropical waters of the South Pacific and Indian Oceans. Charles Darwin correctly theorized that the islands originated as coral reefs on the sides of sinking volcanoes. As the volcano disappeared beneath the waves, the coral grew upward remaining as a ring shaped chain of small islands separated by inlets.

The typical atoll has a flat living area next to the lagoon, 3 to 4 ft in elevation. The seaward or out- ward facing edge of the atoll, consists of a mound of coral fragments, tossed ashore during storms. This outer ridge may have elevations of 10 to 20 feet but is generally not habitable because of its ex- posure to storm waves. Most atoll islands support small populations of a few hundred souls but the total populations of the nations (each consisting of several widely spaced atolls) range from 2,000 (Tokeau) to 10,000 (Tuvalu) to 269,000 (the Maldives). These tiny countries have few resources with which to respond to sea level rise and have no high ground for escape. The only possible response to sea level rise is abandonment of their islands along with some of their traditions and their way of life.

Already a number of atolls are suffering from salinization of ground water. On some Marshall Island communities, crops are grown in abandoned oil drums to avoid the salty soils. This loss of freshwa- ter supply will likely drive the inhabitants away well before the sea level rise inundates them. Resi- dents of the Carteret atolls have already been moved to Papua, New Guinea, Tuvalu has a refugee arrangement with New Zealand and The Maldives are considering purchase of a site in Sri Lanka to transplant their entire nation.

Some atoll nations consider the rising sea level to be a civil rights issue and are considering lawsuits against the western nations responsible for excess CO2 production. Whatever happens, it is clear that the atoll nations are the canaries in the mine as far as sea level rise is concerned. Hopefully the world will take note and realize the implications for their own cultures.

– Orrin Pilkey

Kiribati, the Maldives, the Marshall Islands, $300,000-400,000 per individual to make Tokelau, and Tuvalu are all Island Nations. the move, or a total of about $200 million to All are threatened by the rising sea and none move the entire community of Shishmasref’s has higher ground on their islands. Their 600 people. And there will be losses to their populations will have to find new homes in subsistence culture that will be harder to other countries, but the Maldives has found quantify. that receptivity by other countries to accept their population is low. And the threats to According to the Government Accountability cultural identity when nations move must Office Report (2009), 31 Alaskan villages are also be dealt with. in imminent danger of flooding and coastal erosion related to climate change. At least Some Native Villages in Alaska includ- 12 of these villages are at some stage in the ing Shishmasref on Sarichef Island and relocation process. Kivalina are developing plans to move their entire communities. The cost will be high,

COASTAL HAZARDS 17 The Allure Of The Coastal Zone The coastal zone has been a magnet for humans throughout most of modern human history. It offers a rich and constantly changing array of aesthetic pleasures, bountiful supplies of seafood, and more recently, major economic benefits that result from coastal industries such as tourism, fishing, shipping and transportation. The coastal zone can be a dynamic, inspiring, calming, exhilarating, and dangerous zone to live in, and more than half the people in the U.S. and the world live there. The hazards—the sources of the danger—are increasing, but it is still the location of choice for many humans. Perhaps at no time in human history that stretches back over some 100,000 to 200,000 years has it been as risky for humans to live along the coast as now, and most coastal scientists believe the danger levels may well increase significantly over the next century and perhaps longer, primarily as a result of climate change.

The United States has nearly 88,000 miles of ocean, estuarine, and Great Lakes shorelines with an amazing variation in natural and human-altered characteristics. The coastal zone is an example of a tightly coupled human-natural system.

18 COASTAL HAZARDS A recent study (Organization for Economic Cooperation and Development, OECD 2007, www.oecd.org/dataoecd/16/10/39721444.pdf) ranked the ten most vulnerable cities in the world in terms of the potential for property damage as a result of flooding from a higher sea, not including any storm surge impacts. The cities are listed below in decreasing order of vulnerability and are shown in Figure 1.

1. Miami Using the same criteria, OECD ranked the 2. New York/Newark vulnerability of major U.S. cities to flooding 3. New Orleans from sea level rise. 4. Osaka/Kobe 5. Tokyo 1. Miami 6. Amsterdam 2. New York/Newark 7. Rotterdam 3. New Orleans 8. Nagoya 4. Tampa/St. Petersburg 9. Tampa/St. Petersburg 5. Virginia Beach 10. Virginia Beach 6. Boston 7. Philadelphia Five of the 10 cities most vulnerable to sea 8. San Francisco/Oakland level rise and inundation are in the United 9. Los Angeles States. 10. Houston

If one adds storm surges to the simple drowning scenarios modeled by the OECD, risks to coastal cities increases—in some cases significantly.

COASTAL HAZARDS 19 20 COASTAL HAZARDS Hurricanes and Other Coastal Storms: A Growing Threat

Hurricanes are responsible for most of the storm-related coastal property damage in the United States, but other types of storms, particularly nor’easters on the east coast, so’easters on the Gulf coast, and El Niños on the west coast are also important. Nearly 90 percent of presidential disaster declarations from 1964 to 2007 were in response to weather-induced hazards by flood from hurricanes and other severe storms. During the relatively hurricane- free period from the 1960s until 1989, the majority of today’s coastal residents and property owners did not experience the full force of a hurricane. This led to apathy and a disregard for the hazard posed by hurricanes. A series of hurricanes in rapid succession: Hugo, Bob, Andrew, and others—and more recently Katrina and Rita—changed all that. Unfortunately, in spite of widespread recognition of the hazard, post-storm recovery of hurricane damage in the U.S. often has consisted of replacement of destroyed buildings with larger buildings on the same sites. Heavy rains and high surf from storms associated with the 1998 The Galveston Hurricane of 1900 was the deadliest hurricane in U.S. history. The City of El Niño event produced severe Galveston lost 6,000 to 8,000 lives and the entire Galveston Island may have lost up to 12,000 erosion along the California lives.5 Lake Okeechobee Hurricane (1928) was the next deadliest hurricane with 2,500 lives coast, leading to major property lost, followed by Katrina (2005) with nearly 2,000 lives lost. losses.

Paul Neiman, Environmental Technology Laboratory, NOAA.

5. Estimates vary from 6,000 to 12,000 lives lost with 8,000 being the most frequently cited number.

COASTAL HAZARDS 21 The five deadliest hurricanes in U.S. history between 1900-2008 are listed in the box below.

Hurricane destruction comes from high winds, and particularly from storm surges. Improved building codes and better construction in recent years have reduced wind damage. Storm surges with accompanying storm waves on top of them are a bigger challenge. They result from the interaction of high winds and low atmospheric pressure beneath the storm. As the storm approaches landfall, surface winds push water onto the coast. The height of the surge is amplified in shallow water areas such as the Gulf of Mexico. Hurricane Katrina brought the highest storm surge—up to 30 feet—on record in the U.S. This massive wall of water was responsible for most of the loss of life and property.

The ten costliest hurricanes in U.S. history between 1900-2008 are summarized in the chart above. Much of the increase in the cost of damages caused by hurricanes over the past several decades is the direct result of the large amount of new construction along the coast. For example, the great Miami hurricane of 1926 caused about $76 million in damages. But when Hurricane Andrew, a storm of comparable size and intensity, struck southern Florida in 1992, the damages were on the order of $30 billion (dollar values adjusted for inflation), reflecting both the current size and high value of Miami’s buildings and infrastructure.

22 COASTAL HAZARDS New Orleans after Katrina.

While the U.S. has experienced a number reports of up to 75 inches. Deaths caused of devastating hurricanes in recent history, by catastrophic flooding made it the sec- Central America and the Caribbean have ond deadliest Atlantic hurricane in history; experienced even more disastrous hurricanes nearly 11,000 people were killed and nearly in terms of loss of human life. Hurricane 3 million were left homeless or missing. The Mitch (1998) was one of the most powerful flooding caused extreme damage, estimated hurricanes on record in the Atlantic basin, at over $5 billion (1998 USD, $6.5 billion with maximum sustained winds of 180 mph. 2008 USD). Because of its slow movement, Hurricane Mitch dropped historic amounts of rainfall Hurricane Mitch will be remembered as the in Honduras and Nicaragua, with unofficial deadliest hurricane to strike the Western Hemisphere in the last two centuries. Not

COASTAL HAZARDS 23 since the Great Hurricane of 1780, which killed approximately 22,000 people in the eastern Caribbean, has there been a deadlier hurricane. The President of Honduras, Carlos Flores Facusse, claimed the storm destroyed 50 years of progress.

Some Places And People Are At Greater Risk Than Others

Risks of living along the coast are not evenly distributed in space or in time. The Gulf coast and the east coast of the U.S. are more vulnerable to hurricanes than the west coast. The west coast and Hawaii are more vulnerable to El Niños and tsunamis than the east coast. At any given location at any given time, risks are not evenly distributed across different socio- economic groups. The poor, the sick, and the elderly usually are most vulnerable

Deaths caused by hurricanes have been reduced significantly by improved forecasting and early warning systems in combination with realistic evacuation plans. The deaths from recorded hurricanes pale in comparison to the deaths from the December 2004 Indo- nesian tsunami that claimed nearly 230,000 lives in eleven countries. The tsunami inun- dated coastal communities with surges up to 100 feet high. It was one of the deadliest natural disasters in recorded history. Indonesia, Sri Lanka, India, and Thailand were hardest hit. The earthquake that produced the tsunami had a magnitude of between 9.1 and 9.3 and was the second largest earthquake ever recorded. This earthquake had the longest duration of faulting ever observed, between 8.3 and 10 minutes. It caused the entire planet to vibrate as much as 0.4 inches and triggered other earthquakes as far away as Alaska.

Although climate change will not affect the frequency of tsunamis since they are triggered How Will Global Climate by geologic events—earthquakes, volcanic Change Affect Hurricanes and eruptions, large slumps—and not by atmo- Other Tropical Storms? spheric events, their effects will be magnified by a higher stand of sea level. While this is still a subject of debate, many scientists believe that the intensity and the frequency of hurricanes and other tropical storms, will increase as a result of warming of

24 COASTAL HAZARDS the upper ocean. Storms can intensify quick- that result from climate change will increase ly within 24 to 48 hours of landfall if they the destructive potential of tropical storms. pass over warm ocean waters such as the Gulf In the North Atlantic the picture already Stream, the Florida Current, and the Gulf of seems to be clear. Observations indicate that Mexico. Because of the relationship between there has been an increase in the frequency storm intensity and warm ocean waters—the of tropical storms and major hurricanes in source of the storm’s energy—many experts the North Atlantic, particularly since about are convinced that rising ocean temperatures 1970, and this correlates with increases in

COASTAL HAZARDS 25 sea surface temperatures of tropical waters. Observations of the increase in the frequency and intensity of those hurricanes that make landfall in the South Atlantic are less con- vincing. Models indicate that it is likely that future tropical cyclones—typhoons and hurricanes—will become more frequent, more intense with higher peak winds, and have heavier precipitation—all as a result of warming of the surface layer of the ocean. The risks from these storms to coastal communities will be increased further because of the rise of sea level.

Coastal Populations at Risk

Twenty-three of the nation’s 25 most densely populated counties, and 10 of the nation’s most populous cites are found in coastal areas. More than 50% of the U.S. population lives within 50 miles of a coast within the nation’s 673 coastal counties in 30 coastal states. These counties make up less than 20% of the nation’s land area. Between 1980 and 2003, coastal counties grew by 33 million people, or 28%. In the entire Southeast the increase over this period was 60%—and Florida’s coastal population rose by 75%. More than 60 percent of homes and buildings within 500 feet of the shoreline are located along the Atlantic and Gulf coasts— the nation’s fastest growing coastal areas.

Worldwide, more than half of the world’s population lives within 50 miles of a coast and it is estimated that nearly 75% of the world’s population will live along the coast by 2050. This is happening not only in the developed world. Two-thirds of Southeast Asian cities with populations of 2.5 million or more are located along the coast, and of 77 major cities in Latin America, 57 are on the coast.

As more and more people live and vacation along the coast, more lives, property, and dollars are put at risk from coastal hazards and the risks are increasing. The rising sea and more intense and more frequent tropical storms that result from climate change are making living near the coast riskier than ever. The risk is not just to beachfront property, but often extends inland, especially on barrier islands.

26 COASTAL HAZARDS Adapting to a New Normal The response to sea level rise will vary from dealing with a rising sea and more intense community to community depending on tropical storms and destructive storm surges. environmental concerns, economics, politics, The strategies must identify critical areas to local priorities, the type of coast, and many be protected —both natural and human- other factors. Careful community planning built—and other areas that should be left that results in formal adoption of policies to untouched, and where appropriate, those deal with a rising sea and strict enforcement from which to plan a strategic systematic of those policies will be required. relocation.

Policies to Nudge Us in the For starters, we should stop providing incen- Right Direction tives to build near the ocean in flood-prone National, state, and local policies are needed areas and to rebuild after serious damage or to develop comprehensive strategies for destruction by flooding. Second, we should

COASTAL HAZARDS 27 Barrier Islands: Vanishing Beneath The Waves

Barrier islands, there are around 2200 worldwide, can be found on the rims of all the continents except Antarctica. About 12 % of the world’s open ocean shorelines are lined with these islands which, in the temperate zone, are much sought after for ocean view development. These long, thin and low elevation islands, are made up of unconsolidated sand or gravel and are particularly susceptible to sea level rise.

Barrier islands are among the most dynamic features on the surface of the earth; capable of landward migration in their entirety in response to a rising sea. All this flexibility however is completely lost when the islands are covered by buildings and the inhabitants choose to fight nature and hold the shoreline in place.

The U.S. has more barrier islands (total length of 3054 miles,) than any other country. Distant second, third and fourth are Mexico (1392 miles), Russia (1020 miles) and Australia (905 miles). The Russian barriers are mostly undeveloped and located in cold Siberia, but the U.S. islands are in a more favor- able climate hence the hundreds of miles of high rise-lined islands, particularly in Florida. Although there are many candidates for the most immediate sea-level-rise endangered American island, the west end of narrow, low Dauphin Island, Alabama is certainly a top candidate among Gulf of Mexico islands as is Topsail Island, North Carolina on the East Coast. On a state level, because of the thou- sands of immovable beach front high rises, Florida is in the worst shape of all for any kind of flexible response to sea level rise

There is wide agreement that the anticipated 3-foot sea level rise by the year 2100 will mean the end of barrier island development except when islands are completely surrounded by massive seawalls and have no remaining beaches. Development will end because the shoreline retreat will be unstoppable. But there is an economic problem. When the barrier islands are in deep trouble and miles and miles of costly seawalls are required to protect buildings, the coastal cities will also be in trouble. Who will get the money? Manhattan or Dauphin Island? The choice is obvious.

– Orrin Pilkey

take full advantage of the inevitable flooding communities understand at a deep visceral events that are occurring and that will con- level the need to acknowledge that we must tinue to occur in the near-term. Instead of adapt to a “new normal”, and it is that “new focusing exclusively on “getting back to nor- normal” that we should be planning for and mal” as quickly as possible, we should help acting upon—now!

28 COASTAL HAZARDS Some steps that might be taken include: A Community Framework for • Prohibit new construction in areas pro- Responding to Sea Level Rise jected to be flooded by sea level rise on and Inundation beachfront areas not already developed.

• Evaluate existing costal infrastructure Define The Problem & State It Richly (e.g. sewer, water, storm water runoff I. Explore the issues of Sea Level Rise and systems, electric generating plants) as Inundation with the community to to its ability to withstand the predicted develop a shared vision of what is at risk rise of sea level and plan replacement in and the qualities stakeholders want to appropriate areas where necessary. protect in the face of a rising sea. II. Identify the geographic scope of the • Construct all new coastal infrastructure project area and the time scales of beyond reach of a 7-foot sea level rise. concern. III. Identify and recruit critical partners and • Enact a moratorium on construction of stakeholders and clarify roles and high-rise construction in areas that are responsibilities. likely to be impacted by 21st century sea level rise. High-rise buildings are, for Gather The Data, Information & Tools all practical purposes, immovable and IV. Characterize the current and future make future flexible response to sea level states of Sea Level Rise and Inundation rise virtually impossible. for the Project area. V. Identify critical data, information, and • Discourage or prohibit repair or replace- tools that need to be refined or ment of seriously damaged shorefront developed to reduce uncertainty. buildings in high risk areas. VI. Secure or develop the necessary data, information, and tools. • Require that new buildings in flood- prone coastal areas be constructed to be Identify & Explore Alternative Strategies readily moved if needed in response to VII. Identify and evaluate the various strate- sea level rise. gies for dealing with the projected Sea Level Rise and Inundation scenarios to • Move buildings back or demolish them protect the qualities identified in Step I. as the advancing sea reaches them. Build & Sustain Capacity and Support Many of these strategies would be unpopu- VIII. Develop a comprehensive lar and might be challenged in court. communication strategy. IX. Build the institutional capacity and In a workshop on December 3-5, NOAA and the political will to execute the the USGS developed a template for helping strategies selected. communities—the places where land-use de- X. Institutionalize the program and keep cisions are made—to plan for and adapt to a current. higher sea level. Elements of the template are summarized in the box at right.

COASTAL HAZARDS 29 The proposed framework calls for each community to develop a vision for a sustainable future under a variety of sea level rise scenarios, a vision that protects the qualities valued by the community. Better tools are required for predicting and responding to different sea level rise scenarios. The development of these is primarily the responsibility of the Federal Govern- ment. They include:

• Better, more accurate site specific data and information

• Local and regional sea level rise data.

• Inundation maps for different sea level rise scenarios.

• Maps of resources at risk —societal and natural—at different sea level elevations, with valuations of those resources.

• A Federal Flood Insurance Program that does not provide incentives to build or rebuild in areas vulnerable to sea level rise and inundation.

• Better flood forecasting models and other analytical tools.

• Analyses of the efficacies and costs—both capital and maintenance—of different engineering approaches and their environmental consequences.

• And, of course, leadership will be a key factor. Since solutions to sea level rise-inundation problems must be adaptive solutions—some with engineering components—they require support by affected populations. The challenge for local leaders is considerable. For most the greatest impacts will not occur during their terms of office and there may be little incentive for them to tackle this issue.

Resilient Coastal Communities

A resilient coastal community is a community that has been developed, or redeveloped, to minimize the human, environmental, property losses, and the social and economic disrup- tions caused by natural disasters. Resilient communities are attuned to the natural fluctuations of nature and have a greater capacity to tolerate environmental extremes than less resilient communities.

It has been shown that healthy, productive natural coastal environments such as wetlands, mangrove forests, and beach-dune systems provide some level of support against storms and storm surges. Unfortunately, development took a toll on many natural coastal ecosystems before their protective value was recognized.

The challenge now is to protect and nurture those ecosystems that remain, and to create and sustain new wetlands, mangrove forests, and other coastal ecosystems to help buffer storms and storm surges in the future. These measures are important ingredients in any overall strategy to create more resilient coastal communities, but the magnitude of the challenge should not be underestimated. As noted earlier, before human dominance, most coastal ecosystems migrated landward to keep pace with the rising sea. Now, those pathways often are blocked with infrastructure to support coastal communities along some coasts. We will need to identify new sites for creation of wetlands and provide corridors for them to migrate landward as sea level continues to rise throughout this century.

30 COASTAL HAZARDS Inundation Maps

Maps for 2050 projecting the impact of changes can be used to estimate the severity and frequency of shoreline inundation. (The California Energy Commission’s, San Diego Foundation 2050 Study, 2009.)

2050 Coastal Inundation: Oceanside Beach, CA. Tidal fluctuations alone (purple) appear to inundate portions of sandy beach and wetland. Adding run-up from moderately common wave events (blue) floods south jetty and portions of beach. Moderately rare wave events (green)flood majority of north beach. The effects of shoreline erosion are not included.

– Julie Thomas

COASTAL HAZARDS 31 It’s clear that not only is natural capital— Katrina in Versailles, commonly known as healthy productive natural ecosystems— “Viet Village”, in eastern New Orleans. Viet important in contributing to a community’s Village is a community of Vietnamese im- resilience, but social capital as well. Social migrants. The impacts of Hurricane Katrina capital refers to the capital that is built strengthened an already strong community. within and among social networks. Social Stores and restaurants reopened relatively capital is a critically important ingredient of quickly and the people worked together to resilient communities. Instead of rioting and restore homes and businesses. The church looting that sometimes follows disasters, in played important coordinating and support- communities with large reservoirs of social ive roles by providing transportation, food, capital the dominant behaviors are coopera- relief, and temporary housing. Most residents tion, assistance, and support. returned to Versailles, unlike residents of many other parts of New Orleans. The importance of social capital was illustrat- ed in dramatic fashion following Hurricane

32 COASTAL HAZARDS Using Web Cams To Forecast Erosion Events

Bill Sargent/Barbara Di Lorenzo

Many coastal communities host web cams to waiting for the tide to turn. On my computer allow beachgoers to see what conditions are screen I could see the beach receding from like before they pack up their cars and drive the right so it looked like a two-dimensional to their favorite beaches. These same cameras graph. It was easy to make predictions be- can also be used to predict erosion events. cause the beach was eroding at an average robust rate of ten feet a day. I could actually In 2007, an April storm broke a new inlet see an individual wave wash in, tear off a through the barrier beach that protects foot of sand, then withdraw. Chatham, Massachusetts on the elbow of Cape Cod. As the inlet migrated north during Soon I realized, that during a storm, or a run the following two years, it put a dozen beach of high course tides, the rate of erosion might homeowners at risk. They needed to know increase to 20 feet a day and during periods when their houses might wash away, so they of calm weather and moderate tides the rate could make significant financial decisions. of erosion would be less than 5 feet. By using a tide chart, a weather report, and the dis- A group of citizen scientists decided to put tance of a house from the end of the beach I together a website to provide such informa- could use simple math to give homeowners tion. My job was to use a web cam to make an accurate assessment of when their houses daily erosion reports. Our camera was ideally might be washed away. located on the mainland aimed toward the barrier beach a half a mile away, where a – William Sargent dozen beach homes sat in a row like seagulls

Google: utube Sea Level Rise Pleasant Bay

COASTAL HAZARDS 33 The Contribution Of Healthy Coastal Ecosystems In Creating Resilient Coastal Communities

One of the best ways to reduce risks from hazards is to maintain healthy coastal ecosystems—beach-dune systems, wetlands, mangroves, and coral reefs. The protective effects of mangroves, wetlands, other coastal vegetation, and beach-dune systems were noted following numerous hurricanes. Examples include:

• The coast of the Yucatan Peninsula, Mexico, after Hurricane Gilbert in 1988.

• Pawley’s Island (SC) after Hurricane Hugo in 1989. Over wash penetration and storm wave damage to property was noticeably less where maritime forests had been kept in tact than in areas where they had been cleared.

• The dense mangrove forests of south Florida helped reduce the coastal impacts of Hurricane Andrew in 1992.

• Some experts have stated that had more of the original wetlands been intact, some of the $90-100 billion damages to New Orleans and surrounding areas from Hurricane Katrina (August 2005) would have been avoided.

The benefits of healthy coastal ecosystems are not limited to hurricanes. Assess- ments of damage following the Indonesian tsunami (December 26, 2004) showed clearly that coastal communities with largely undisturbed coastal ecosystems and healthy offshore coral reefs suffered less loss of human life and property damage and than those where these protective natural systems had been destroyed.

It’s clear that healthy, productive natural coastal ecosystems can contribute to reducing the risks to coastal communities from coastal hazards, to reducing their vulnerability, and to increasing their resiliency.

Doug Harper & Adam Stein

34 COASTAL HAZARDS The Roles of Science

Better, more reliable flooding models, hurricane projection models, and early warning systems, have reduced the loss of life from hurricanes and other tropical storms. Significant (15-20%) advances have been made in the ability of hurricane storm prediction models to predict storm tracks accurately. Improve- ments in predicting storm intensity have been less impressive. Even small improvements in model forecasts can save many lives and pre- vent property damage b y millions of dollars. This continues to be an area of active development by NOAA. http://www.noaanews.noaa.gov/stories2005/images/Katrina-08-28-2005-15452.jpg

It is estimated that preparation in the days and hours leading up to an anticipated landfall of tourists are willing to obey evacuation orders, a hurricane costs approximately $1 million local residents often resist evacuation because per mile of coastline. With current forecast- they have “been through it before.” Social ing tools, about 125 miles of coastline can scientists can be helpful in structuring mes- be warned—and evacuated, if necessary—48 sages and in designing dissemination systems hours in advance of a major hurricane making to elicit the desired responses. landfall. Inaccurate warnings result not only in high costs but also loss of public confidence Although better forecasts and warning process- in forecasts, often causing residents to ignore es have helped save lives by providing more subsequent warnings. lead time for evacuation, the tremendous growth of development and human popula- Forecasting hurricanes and other tropical tion in coastal regions is so rapid that the loss storms is challenging because of the uncertain- of life and property from coastal disasters can ties and non-linear interactions of the various probably be expected to increase in the future. driving forces, and how they will be influ- The rise of sea level will only exacerbate the enced by coastal topography, changes in water problem. temperature, and other factors. This uncertainty makes it difficult for coastal managers Science also has provided valuable informa- to assess risk, to identify the most vulnerable tion that could enlighten where and how regions of the coast, and to take appropriate people should build—and rebuild—along action far enough in advance of the projected coasts; which areas are most and least ame- landfall to reduce loss of life and property. nable to engineering solutions; and which areas could be candidates for development of Early warning has another component—get- plans for systematic retreat and relocation. The ting the information generated by computer extent to which scientific information is used models to the people at risk in a timely way for these purposes is growing. and in forms that allow them to take appropriate action. Information dissemination systems Social scientists of all kinds can help gener- must exploit a range of technologies and ate the needed data and transform them into distribution systems to ensure redundancy and information and strategies in which decision- robustness during disruptive events, and to get makers and the public can have confidence. to the maximum number of people from di- This will require more inclusive, open, and verse demographic groups. Experience in bar- transparent processes with substantial and rier island communities shows that although sustained stakeholder involvement.

COASTAL HAZARDS 35 The Roles of Engineering

There is a belief among some that a “dooms- day sea level rise scenario” will not happen and that if it does, it is far into the future, and by then we will have the scientific and engineering know-how and the financial resources to stop the rising sea from invading from developed countries. Even well off and drowning coastal communities across countries will have to decide which areas to the country and around the world. For centu- protect, and from which to strategically re- ries humans have built structures to protect treat if they are to avoid major loss of life and the shoreline from erosion and flooding, property and serious economic and societal but most have been fairly modest in spatial disruption. The United States is among them. extent. The core strategy in many locations will be to adjust to a ‘new normal’ by moving away Sea level rise, severe coastal erosion and from the sea to higher elevations. Engineer- inundation are happening now, and all the ing will play major roles in the design and evidence points to a continued rise of sea execution of these strategies. level, probably at an accelerated pace, and more active tropical storms superimposed Engineering structures often are referred upon this rising sea. Engineering solutions to as “hard solutions” to distinguish them will probably be part of every coastal state’s from so-called “soft solutions” such as beach strategy and every nation’s strategy, but there nourishment and planting vegetation to are no affordable engineering fixes that can stabilize dunes. The structures fall into two be applied on a state-wide or country-wide basic categories: those perpendicular to the scale, and even if there were, the effects on coast and those parallel to it. Hard solutions coastal ecosystems, recreational beaches, to managing coastal hazards have grown coastscapes, and on human uses of the increasingly out of favor with many environ- coastal zone would probably not be accept- mental groups and coastal managers primar- able. The Netherlands is a nation that has ily because of their cost and their unintended successfully held off the assaults by the sea, consequences. Engineering solutions may and even reclaimed land from the North Sea, be important in dealing with a rising sea in but things are different now, and even they many situations on a transitional basis and are re-thinking their strategy. in a smaller number of others on a more permanent basis. Poor countries do not have the resources—financial or technical—to invest in responding Engineering will be important in design and to the rising sea. They will require assistance construction of buildings that can greatly

36 COASTAL HAZARDS Living on the edge in Seal reduce property damage and even loss of life. solutions will play important roles Beach, Ca. Average 10.3 Structures elevated on well-engineered stilts in this “new normal”, particularly feet above sea level. that allow storm surges to pass under the in protecting urban areas in which structure unimpeded, reduce property dam- society has made huge investments age and loss of life. Structures aligned in the in infrastructure. direction of flow of storm surges, rather than perpendicular to it reduce damage and strong foundations provide added protection against scour and the undermining of structures. The choice of materials is also important.

Engineering solutions—both hard and soft— should be evaluated as transitional strategies to a “new normal” of sea level, and to achieving and sustaining community resilience under those new conditions. Engineering

COASTAL HAZARDS 37 Closing Observations

As coastal populations continue to increase, risks to human life and property also increase. Risks are driven not only by the num- bers of people, but by the nature and extent of coastal development and its impacts on natural ecosystems. Coastal hazards will increase as a result of climate change with a rising sea and more frequent and more intense tropical storms.

Well before the end of this century, depending upon the sea level rise scenario that plays out, it may become impractical to protect more than very restricted and mostly urban sections of the coastline. Strategic retreat may be the prudent course of action except Achieving this end state will require a in locations such as major cities and ports broadly-shared vision of what society wants where societies have made huge investments our coastlines to look like at some future in infrastructure and retreat is not a plausible time horizon and one that is consistent option. with evolving natural processes. It must also be one that society is prepared to invest in As the NRC document “Coastal Hazards” securing. It is a complex, challenging design points out: “Comprehensive, cohesive poli- problem. Sea level rise and inundation and cies on coastal protection need to be based the inevitable collision with human society on the best possible information, from falls into the category of what are called improving coastal mapping to enhanced “wicked problems.” Wicked problems are weather and impact forecasting. Armed with problems that cannot be solved. They are knowledge gleaned from these tools, gov- problems that can only be managed, to be ernment officials, coastal managers, prop- kept within certain bounds, and to do that erty owners, and everyone who enjoys the requires a rich formulation of the problem nations’ coastal areas should work toward to capture its multiple and complex dimen- developing a long-term plan for ensuring sions—scientific and societal—to ensure that that U.S. coastal resources will be sustainable the correct problem, or set of problems, is ad- for future generations to enjoy.” dressed. This should be a priority for coastal

38 COASTAL HAZARDS communities, states, the both the developed world and in the devel- U.S. Government, other oping world and it is likely that response to nations, and interna- sea level rise on coastal cities will consume tional bodies. Research much of the available resources and funding. has shown that under They include: Miami, New York, Los Ange- conditions of deep les, Tokyo, Mombasa, Shanghai, Jakarta, and uncertainty such as Dhaka. Trillions of dollars have been invested this, the most prudent in infrastructure to support them—all dur- approach is not to ing a period of relative stability of sea level. search for the optimum That’s about to change. Worldwide sea level solution, but rather to rose about 0.6 feet over the past 100 years. identify a portfolio of Over the next 100 years it is projected to strategies that are robust rise by 3, 5, 7 feet, or much more depending across numerous pos- upon what happens to the Greenland and sible outcomes that in the west Antarctic Ice sheets. Superimposed the aggregate minimize upon this inexorable rise in sea level will be the potential for regret. an increase in the intensity, and probably the frequency, of tropical storms—hurricanes Never in the history of and typhoons. All driven by global climate humankind has living change. near the coast been riskier. And the risk is Sea level rise, inundation of coastal areas, increasing. Throughout erosion of shorelines, and increased tropi- most of the history of cal storm activity are the most immediate modern civilization, sea and direct effects of global climate change level has been relatively on humans and human society. More than stable. Since the Industrial Revolution began half the world’s population lives within the some 200-250 years ago, global sea level has coastal zone, and the percentage is projected risen only about a foot. In the same period to grow to 75% before the end of this cen- the world’s population has increased by tury. Instead of migrating toward the coast, nearly 700%, from less than a billion to 6.8 we should begin now to make plans to move billion away from much of the coast in a thought- ful, planned, systematic and sustained way to We are experiencing the two biggest migra- minimize human and financial dislocations. tions in human history—the migration to the It’s a design problem. coast and the migration into cities. In 2008 for the first time in human history more than half the world’s population lived in towns and cites. By 2030 more than 5 billion people will live in towns and cities with the growth concentrated mostly in Africa and Asia.

More than two-thirds of the world’s cities with populations greater than 5 million are located along the coast. These cities are in

COASTAL HAZARDS 39 Appendix A