UC Santa Cruz

Each coastal disaster is followed by the inevitable debates about whether rebuilding is the right decision. Hurricanes Sandy and Katrina are good examples, as were the damaging El Niño events along the California coast in 1982-83, 1997-98, and 2009-10. Coastlines globally have been migrating landward since the last Ice Age ended about 18,000 years ago, and all indications are that this trend will continue in the decades and centuries ahead, most likely at an increased pace as the rate of sea-level rise increases. Retreating from the shoreline is not a new approach, and there are many communities and neighborhoods along the coasts of the United States and elsewhere where relocation has occurred and where formerly developed parcels are now underwater. Documenting these lost neighborhoods and those that are in the process of disappearing today is important in providing a longer-term perspective of what we face as a state and as a nation. Coastlines are in constant flux, and with few exceptions, they are migrating inland, either gradually or more rapidly during extreme events. Although there are short-term or temporary approaches that have been used for decades to hold back the ocean, they all have their limits. Communities need to assess their vulnerabilities to future sea-level rise and begin to adapt or prepare for the inevitability of a changing shoreline.