The thing about sea level is that for any particular glacier in Antarctica and Greenland, it can melt really slow at start, but once the bottleneck part melts,

The thing about sea level is that for any particular glacier in Antarctica and Greenland, it can melt really slow at start, but once the bottleneck part melts, it can be very rapid. Understanding this mechanism, trying to estimate future sea level rise solely based on past sea level is a very bad idea!