Dozens of reports predict—as best as scientists can—the level of sea rise and the expected timeframe. Another factor is the speed at which carbon-reduction policies can achieve their goals. It’s difficult work and hardly precise.
But the most recent scientists’ report for the state of California’s Ocean Protection Council offers the best look at the possibilities, offering a range of scenarios and assigning probabilities to the projections. For example, if officials do everything humanly possible to prepare for sea-level rise, there is still a 67 percent probability that the San Francisco Bay Area will experience sea rise between 1 foot and 2.4 feet by 2100. Absent any response, that range increases to 1.6 to 3.4 feet.
Scientists often explain that the Pacific Ocean is not a bathtub — the sea will rise at different rates in different places, dictated by variants such as the presence of seawalls, wetlands and the shape of the ocean floor. The actual rate of rise is very much a local phenomenon. Overall, though, the report concludes that if nothing is done to slow global warming, the Pacific Ocean will rise 10 feet along the California coast, a rate of rise that is 30 to 40 times faster than the previous century.