Another key variable in regional sea level change is the increasing freshwater input that is predicted for the 21st century.  This freshwater would come from melting land ice, changes in land surface hydrology and/or changes in groundwater extraction.  Depending on where the input is entering the ocean will determine the magnitude of regional variation (Figure 13.18). Taking into account all these contributors, the CMIP5 ensemble models runs are able to project regional sea level change on a decadal scale up to 2100 (Figure 13.20).  It is very likely that 95% of the world’s ocean will experience a positive relative regional sea level change in the next century.  Those regions that will experience a negative relative sea level change are located in areas of isostatic rebound resulting from melting ice sheets.  Sea level could rise 55 cm along coastlines for RCP 4.5 and as much as 80 cm for RCP 8.5.  Under RCP 8.5 it is possible that 72% of coastlines will experience a change equal to +/- 20 % GMSLR.  However, due to smaller scale dynamic processes, the natural variability will be significant such that only longer-term observational records will be able to display any trends.  Additionally, predictions of regional scale GMSL changes are dependent on the initial conditions so there is still uncertainty attributed to the observations used to initialize the models.