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

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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, in- cluding large cities, along with the infrastruc- ture—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 rap- idly 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 cata- strophic 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 as- sociated 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 de- cades 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.
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