Cold, glacial epochs have been the rule for a million years or more. Only once every 120,000 years or so does the earth warm to present temperatures, and then only briefly, for about 10,000 years. We are now nearing the end of one of these periods.
Sea level follows trhe temperature,
and is usually much lower, by up to 350 feet, than at present. Here is
the sea level for the past 100,000 years, and also for the past 10,000
years, the so-called "Holocene" specifically for the San Francisco Bay
What is the impact on the state of California?
Most of the time our bays don't
exist, and you'd have to walk a long way from the Golden Gate to get to
Superimposed on this process is the steady faulting that affects California terrain, both north and south. Compare this with the more complex condition found in glaciated coastal areas such as Boston.