0.3 mm/year is an order of magnitude off.
The satellite-measured average rate of SLR is about 3.3 +/- 0.4 mm per year from 1993 to 2009. Satellites can easily measure changes of 0.1 mm in sea level. The rate of SLR is increasing and the total rise in 2100 is expected to be between 1 and 2 meters.