Determining a average sea level
is tricky since there is no absolute standard.
The solid
Earth is always flexing in
complex ways in every different area and
the oceans likewise.
There must be an elaborate procedure for arriving at an average
sea level.
Currently, sea level rise rate
is 0.28 ± 0.4 cm/yr.
By 2100,
sea level rise is expected
be somewhere between 0.1 m and 2.0 m over the present.
There are vast uncertainties in such predictions.
Just extrapolating the current rise rate, we can expect a rise of
∼ 24 cm.
Few people expect the rise rate to stay constant.
So the 24 cm prediction is NOT robust.