How much would rising sea levels depress the Earths crust with the additional weight of water?
The answer to this problem is quite complex. The computation involves computing depressions of distributed loads of a certain size. For example, for a 1 metre load of water over discs of different radii, the vertical displacements at the centre are:- 1 km radius -0.3mm 10 km radius -2mm 100 km radius -11mm Thus, the depression just due to the weight of water in the local area that is flooded is probably only a few tenths of a mm. For the crustal displacement due to an increase in sea level over a whole sea area (such as the North Sea), a larger mass is involved. For example, our work on storm surge loading shows that a storm surge of about 2 metres in the southern North Sea depresses the crust by 20 to 30 mm in near coastal areas.
