Skip to content

California property at serious risk from rising seas

No part of the world famous bay area is safe and San Francisco's Embarcadero and parts of Richmond, West Oakland, Alameda, Sausalito and Alviso will all be underwater unless levees or other protective structures are built, it is claimed.

San Mateo County, including Foster City and Redwood City, would be especially hard hit, while San Francisco and Oakland's airports could both be inundated, the work by the Oakland based Pacific Institute has found.

Dozens of hazardous waste sites and an assortment of power plants, roads and sewer plants are also threatened. Wetlands would be flooded and bluffs along the coast exposed to increased erosion from pounding waves.

The report estimates it would cost $14 billion to build 1,100 miles of dikes, sea walls, and other structures to protect the California coast, plus $1.4 billion a year in maintenance.

While the threat to the California's 1,000 miles of coastline between Oregon and Mexico is of concern, it is dwarfed by the threat to the bay's shoreline here a history of filling wetlands and building on them could be reversed by a rising sea, the report points out.

Assuming sea level will rise 1.4 meters, or about 4.5 feet, by 2100, the report found that nearly 500,000 people would be put into a 100 year flood plain, mostly in Orange County and in San Francisco Bay. That includes residents who are now in the floodplain but protected by levees or other flood protection that would be compromised with higher seas.

Of the properties threatened in San Francisco Bay, half are houses and apartments while a third are commercial buildings.

Sea level at the Golden Gate has gone up about 8 inches in the past 100 years. Climate scientists expect that increase to continue or accelerate over the next 100.

In 2007 the United Nation's Intergovernmental Panel on Climate Change estimated global sea level rise to be between 7 and 24 inches over the next 100 years. But more recent work suggests those numbers, which do not take into account the potential of accelerated ice melting in Greenland and Antarctica, are too conservative.

The figure used by the Pacific Institute study, which was developed at the Scripps Institution of Oceanography in San Diego, is on the high end of estimates of what will occur by 2100. It assumes a high level of greenhouse gas emissions in a world where population growth is steady but economic growth and technological development are slowing down.

California and the Bay Area have led the rest of the US in taking steps to lower greenhouse gas emissions. State law, for example, requires greenhouse gas emissions statewide be lowered to 1990 levels by 2020.