and receded. Vast parts of the world that are today dry land were once ocean bottoms. Today there is clear evidence that the oceans are advancing; scientists dispute the causes—is it global warming due to human activities, or is it an inevitable cycling of global temperatures? To islanders such as those living on the coral islands of Tuvalu and Kiribati, it does not matter; they just know their land is disappearing. So, it is not just the risk of a tsunami that makes the design of port and coastal facilities so important; if the mean sea level rises, some coastal facilities will have a reduced margin of safety; others will simply disappear.

Just what is the margin of safety? Elsewhere I’ve mentioned that the elevation of the Balboa Peninsula where I live is 10 feet above mean sea level—not much comfort there. The same is true of large sections of the Pacific and Atlantic coasts of the United States, as it is of countries ringing the Indian Ocean and of many Pacific Islands. There are two piers, about a mile apart, that are an integral part of our beachfront community. The southerly one, called the Balboa Pier, has a deck that rises 20 feet above mean sea level, while the Newport Pier, a little farther north, is 22 feet above mean sea level. Both piers have restaurants overlooking the ocean, and during daylight hours visitors or people fishing will be on the piers enjoying the view. Would they be safe in a tsunami?

About 15 miles farther north is the giant port complex of the combined Los Angeles–Long Beach harbors. This seaport is the largest in the United States in terms of container ships; every day dozens of giant vessels enter the port from all over the world to discharge goods or to load materials for shipment overseas. There is a long breakwater that protects the harbor; it is 14 feet above mean sea level.

I met with Tony Gioiello, the chief engineer of the Port of Los Angeles, to discuss port design. He told me that the port had contracted with the U.S. Army Corps of Engineers to construct a large-scale hydraulic model of the port, along with its breakwater, various piers, and other features. This model can be used to study tidal effects within the port, seiching, currents, and any other aspects that might affect its operation.

To comply with California’s strict seismic design codes, the cranes and other critical port facilities are designed to withstand a major

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