Estimates of SLR in the literature vary widely, from an observed value of 8-inches per century to about 33-inches per century based on IPCC high estimates. High-resolution global altimetry data, through the end of 2009, suggest that in the last two decades, global mean sea level has increased at a rate close to the upper end of the IPCC projections. This corresponds to an increase in global mean sea level of around 10 inches by 2050 and 30 inches by 2100. However, semi-empirical studies by Rahmstorf, have stated that SLR over the next 100 years could be substantially higher than that suggested by IPCC and could be as much as 55-inches by 2100.
This SLR estimate was adopted by the CALFED Independent Science Board as a plausible, albeit high, value. It is also the basis for long-term SLR estimates recommended by San Francisco Bay regional agencies.