Sea-Level Rise for the Coasts of
California, Oregon, and Washington:
Past, Present, and Future
Committee on Sea Level Rise in California, Oregon, and Washington
Board on Earth Sciences and Resources and Ocean Studies Board
Division on Earth and Life Studies
NATIONAL RESEARCH COUNCIL
OF THE NATIONAL ACADEMIES
THE NATIONAL ACADEMIES PRESS
Washington, D.C.
www.nap.edu
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NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.
This study was supported by the California Department of Water Resources, Contract No. 4600008602; the National Oceanic and Atmospheric Administration, Contract No. DG133R08CQ0062; the U.S. Army Corps of Engineers, Contract No. W912HQ-09-P-0155; and the United States Geological Survey, Grant/Cooperative Agreement No. G09AP00152. Any opinions, findings, or conclusions expressed in this publication are those of the author(s) and do not necessarily reflect the views of the organizations or agencies that provided support for the project.
International Standard Book Number-13: 978-0-309-25594-3
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Cover: Lighthouse Point, Santa Cruz, California. SOURCE: Courtesy of Shmuel Thaler, Santa Cruz Sentinel.
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Advisers to the Nation on Science, Engineering, and Medicine
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COMMITTEE ON SEA LEVEL RISE IN
CALIFORNIA, OREGON, AND WASHINGTON
ROBERT A. DALRYMPLE, Chair, Johns Hopkins University, Baltimore, Maryland
LAURENCE C. BREAKER, Moss Landing Marine Laboratories, California
BENJAMIN A. BROOKS, University of Hawaii, Manoa
DANIEL R. CAYAN, Scripps Institution of Oceanography, San Diego, California
GARY B. GRIGGS, University of California, Santa Cruz
WEIQING HAN, University of Colorado, Boulder
BENJAMIN P. HORTON, University of Pennsylvania, Philadelphia
CHRISTINA L. HULBE, Portland State University, Oregon
JAMES C. MCWILLIAMS, University of California, Los Angeles
PHILIP W. MOTE, Oregon State University, Corvallis
WILLIAM TAD PFEFFER, University of Colorado, Boulder
DENISE J. REED, University of New Orleans, Louisiana
C.K. SHUM, Ohio State University, Columbus
Ocean Studies Board Liaison
ROBERT A. HOLMAN, Oregon State University, Corvallis
National Research Council Staff
ANNE M. LINN, Study Director, Board on Earth Sciences and Resources
MARTHA MCCONNELL, Program Officer, Ocean Studies Board (through September 2011)
COURTNEY R. GIBBS, Program Associate, Board on Earth Sciences and Resources
JASON R. ORTEGO, Research Associate, Board on Earth Sciences and Resources
BOARD ON EARTH SCIENCES AND RESOURCES
CORALE L. BRIERLEY, Chair, Brierley Consultancy LLC, Highlands Ranch, Colorado
WILLIAM E. DIETRICH, University of California, Berkeley
WILLIAM. L. GRAF, University of South Carolina, Columbia
RUSSELL J. HEMLEY, Carnegie Institution of Washington, Washington, D.C.
MURRAY W. HITZMAN, Colorado School of Mines, Golden
EDWARD KAVAZANJIAN, Jr., Arizona State University, Tempe
DAVID R. MAIDMENT, The University of Texas, Austin
ROBERT B. MCMASTER, University of Minnesota, Minneapolis
M. MEGHAN MILLER, UNAVCO, Inc., Boulder, Colorado
ISABEL P. MONTAÑEZ, University of California, Davis
CLAUDIA INÉS MORA, Los Alamos National Laboratory, New Mexico
BRIJ M. MOUDGIL, University of Florida, Gainesville
CLAYTON R. NICHOLS, Idaho National Engineering and Environmental Laboratory (retired), Ocean Park, Washington
HENRY N. POLLACK, University of Michigan, Ann Arbor
DAVID T. SANDWELL, University of California, San Diego, La Jolla
PETER M. SHEARER, University of California, San Diego, La Jolla
REGINAL SPILLER, Azimuth Investments LLC, Texas
TERRY C. WALLACE, Jr., Los Alamos National Laboratory, New Mexico
National Research Council Staff
ELIZABETH A. EIDE, Director
ANNE M. LINN, Senior Program Officer
SAMMANTHA L. MAGSINO, Senior Program Officer
MARK D. LANGE, Program Officer
JENNIFER T. ESTEP, Financial and Administrative Associate
NICHOLAS D. ROGERS, Financial and Research Associate
COURTNEY R. GIBBS, Program Associate
JASON R. ORTEGO, Research Associate
ERIC J. EDKIN, Senior Program Assistant
CHANDA IJAMES, Senior Program Assistant
OCEAN STUDIES BOARD
DONALD F. BOESCH, Chair, University of Maryland, Cambridge
EDWARD A. BOYLE, Massachusetts Institute of Technology, Cambridge
RITA R. COLWELL, University of Maryland, College Park
SARAH COOKSEY, Delaware Department of Natural Resources and Environmental Control, Dover
CORTIS K. COOPER, Chevron Corporation, San Ramon, California
JORGE E. CORREDOR, University of Puerto Rico, Lajas
KEITH R. CRIDDLE, University of Alaska, Fairbanks
JODY W. DEMING, University of Washington, Seattle
ROBERT HALLBERG, National Oceanic and Atmospheric Administration, Princeton, New Jersey
ROBERT A. HOLMAN, Oregon State University, Corvallis
KIHO KIM, American University, Washington, D.C.
BARBARA A. KNUTH, Cornell University, Ithaca, New York
GEORGE I. MATSUMOTO, Monterey Bay Aquarium Research Institute, California
JOHN A. ORCUTT, University of California, San Diego
JAY S. PEARLMAN, IEEE, Port Angeles, Washington
STEVEN E. RAMBERG, National Defense University Pennsylvania State University, Washington, D.C.
ANDREW A. ROSENBERG, Conservation International, Arlington, Virginia
DANIEL L. RUDNICK, Scripps Institution of Oceanography, San Diego, California
PETER L. TYACK, University of Saint Andrews, Scotland, United Kingdom
DON WALSH, International Maritime Inc., Myrtle Point, Oregon
DAWN J. WRIGHT, Oregon State University, Corvallis
JAMES A. YODER, Woods Hole Oceanographic Institution, Massachusetts
National Research Council Staff
SUSAN J. ROBERTS, Director
DEBORAH A. GLICKSON, Senior Program Officer
CLAUDIA MENGELT, Senior Program Officer
KIM J. WADDELL, Senior Program Officer
SHERRIE FORREST, Senior Program Associate
GRAIG R. MANSFIELD, Financial Associate
PAMELA A. LEWIS, Administrative Coordinator
LAUREN L. HARDING, Senior Program Assistant
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Preface
Projections of sea-level rise are increasingly being incorporated into coastal planning at national, state, and local levels. This assessment of sea-level rise for the California, Oregon, and Washington coasts was requested by 10 state and federal agencies:
• California Department of Water Resources
• California Energy Commission
• California Department of Transportation
• California State Water Resources Control Board
• California Ocean Protection Council
• Oregon Watershed Enhancement Board
• Washington Department of Ecology
• National Oceanic and Atmospheric Administration (NOAA)
• U.S. Army Corps of Engineers (USACE)
• U.S. Geological Survey (USGS)
At the committee’s first meeting, each agency described its needs for sea-level information.1 The state agencies need estimates and projections of sea-level rise in their areas to assess coastal risk; to plan investments in water, transportation, energy, and pollution-control infrastructure; to modify design and construction standards; to develop adaptation strategies that will protect the environment and infrastructure against increased salt-water intrusion, coastal erosion, and inundation; and to identify necessary changes in state law or policy. NOAA and the USGS need sea-level information at state, national, and global scales to assess coastal vulnerability and response to sea-level rise; to improve models and forecasts; to develop research priorities; and to develop decision support tools for a variety of users, including the public. Finally, the USACE needs sea-level information to guide water resource investment decisions.
Assessments of sea-level rise at state and regional levels are challenging because data on the geophysical processes involved are relatively sparse and there are no agreed-upon models or approaches for projecting future sea-level rise. Consequently, in addition to searching the scientific literature, it was necessary to consult widely with colleagues and to carry out original data analyses. The results were discussed during four committee meetings in 2011 and countless teleconference and email discussions.
The committee used standard statistical techniques to calculate means, trends, and uncertainties associated with sea-level rise, and to extrapolate recent data into the future. To ensure that the calculated results were sound, the committee verified its results in several ways. Calculations performed using standard statistical packages or the equations and data presented in the report were cross-checked by one or two committee members. This process was used to check the means and uncertainties of the various components of sea-level rise, the tide gage and satellite altimetry measurement errors and corrections, vertical land motion observations and models, and estimates of the effect of gravitational attraction. Calculations that required specialized software, including extracting the steric contribution from model results, calculating trends from satellite measure-
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1 Presentations to the committee by the 10 sponsor agencies on January 12, 2011.
ments and glacial isostatic adjustment (GIA) models, and projecting future sea-level rise, were carried out or checked by a colleague or student of the lead committee member. The method for extrapolating the cryospheric contribution to sea-level rise was developed in collaboration with a statistician, who also verified the results. Where possible, the data and equations for these calculations are provided in the report or the public-access file, enabling an independent check from reviewers.
The committee would like to thank the individuals who briefed the committee; supplied data, figures, or model results; or provided other input or feedback: Jonathan Allan, Brian Atwater, Patrick Barnard, Laura Brophy, John Church, Abe Doherty, Catia Domingues, Peter Gleckler, Chris Goldfinger, Dominic Gregorio, Jonathan Gregory, Eric Grossman, Junyi Guo, Erica Harris, Greg Hood, Masayoshi Ishii, Ian Joughin, Jeanine Jones, Tom Kendall, Paul Komar, Eli Levitt, Sydney Levitus, Becky Lunde, Anne Pardaens, Archie Paulson, Stephan Rahmstorf, Eric Rignot, Peter Ruggiero, Carl Safina, Ingo Sasgen, Armand Thibault, Wouter van der Wal, Hansheng Wang, Kelin Wang, Jeff Weber, Josh Willis, Frank Wu, Patrick Wu, Jianjun Yin, and Phoebe Zarnetske. Special thanks go to Balaji Rajagopalan, who developed the statistical approach for the ice extrapolations; James Foster, who compiled and analyzed leveling data in California; Richard Peltier, who provided details of his GIA models and computed past and future predictions of relative sea-level changes in Washington, Oregon, and California; and Jerry Mitrovica, who provided gravity fingerprints along the U.S. west coast for Alaska, Greenland, and Antarctica. The committee also thanks the students, postdocs, and colleagues who crunched numbers, validated results, and created (and recreated) figures, including Jianbin Duan, Zhenwei Huang, Chungyen Kuo, Darrin Sharp, Scott Waibel, and Yuchan Yi. Without the hard work and contributions of all these individuals, it would have been difficult to complete this report.
Finally, I thank all the members of the committee for their service, some of whom had to go way beyond that usually required for an NRC committee because of the short study period and the complexity of the task. Finally, I thank Anne Linn for her tireless efforts as Study Director and for bringing the report to fruition.
Robert A. Dalrymple, Chair
Committee on Sea Level Rise in
California, Oregon, and Washington
Acknowledgments
This report has been reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the NRC’s Report Review Committee. The purpose of this independent review is to provide candid and critical comments that will assist the institution in making its published report as sound as possible and to ensure that the report meets institutional standards for objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process. We wish to thank the following individuals for their participation in the review of this report:
Linda K. Blum, University of Virginia, Charlottesville
Roland Bürgmann, University of California, Berkeley
John A. Church, Centre for Australian Weather and Climate Research, Hobart, Tasmania
Peter J. Gleckler, Lawrence Livermore National Laboratory, California
Peter H. Gleick, Pacific Institute for Studies in Development, Environment, and Security, Oakland, California
Mark F. Meier, emeritus, University of Colorado, Boulder
Jerry X. Mitrovica, Harvard University, Cambridge, Massachusetts
Antony R. Orme, University of California, Los Angeles
W. Richard Peltier, University of Toronto, Canada
Stephen Price, Los Alamos National Laboratory, New Mexico
Claudia Tebaldi, Climate Central, Princeton, New Jersey, and Palo Alto, California
John M. Wallace, University of Washington, Seattle
Joshua K. Willis, Jet Propulsion Laboratory, Pasadena, California
Although the reviewers listed above have provided many constructive comments and suggestions, they were not asked to endorse the conclusions or recommendations nor did they see the final draft of the report before its release. The review of this report was overseen by Ken Brink, Woods Hole Oceanographic Institution, and Warren Washington, National Center for Atmospheric Research. Appointed by the National Research Council, they were responsible for making certain that an independent examination of this report was carried out in accordance with institutional procedures and that all review comments were carefully considered. Responsibility for the final content of this report rests entirely with the authoring committee and the institution.
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Contents
Geographic Variation Along the U.S. West Coast
2 MEASURED GLOBAL SEA-LEVEL RISE
Gravity Recovery and Climate Experiment (GRACE)
3 CONTRIBUTIONS TO GLOBAL SEA-LEVEL RISE
Glaciers, Ice Caps, and Ice Sheets
4 SEA-LEVEL VARIABILITY AND CHANGE OFF THE CALIFORNIA, OREGON, AND WASHINGTON COASTS
Short-Term Sea-Level Rise, Storm Surges, and Surface Waves
Sea-Level Fingerprints of Modern Land Ice Change
5 PROJECTIONS OF SEA-LEVEL CHANGE
Recent Global Sea-Level Projections
Committee Projections of Global Sea-Level Rise
Previous Projections of U.S. West Coast Sea-Level Rise
Committee Projections of Sea-Level Rise Along the California, Oregon, and Washington Coasts
6 RESPONSES OF THE NATURAL SHORELINE TO SEA-LEVEL RISE
Retreat of Cliffs and Beaches Under Sea-Level Rise
Opportunities for Marsh Restoration and the Effect of Marshes on Storm Wave Attenuation
A Vertical Land Motion and Sea-Level Data Along the West Coast of the United States
B Sea-Level Rise in the Northeast Pacific Ocean
C Analysis of Sea-Level Fingerprint Effects
D Long-Term Tide Gage Stability from Leveling Data