I’m way more worried about mean sea level raising above much of our lower elevations. We’re already raising dikes, also making them wider so they can easily be made even higher in the future, accounting for the most pessimistic of projections, but you can’t really keep water out with dikes when the sea is pushing groundwater up. You can do it like the Dutch but if their pumps ever fail they’re royally fucked. Electricity, availability of huge amounts of energy in general, is not something you want to rely on in these matters if you can avoid it.

We’re probably going to end up with large areas of salt march interspersed by towns on mounds and a couple of lakes to construct those mounds, the dikes only making sure that they’re high, not low, salt marches – not elevation-wise but regarding how salty they are, how often they get flooded. The alternative would be to give up the marches completely and knowing our Frisians no that won’t happen. Barley and sugar beets are naturally salt-resistent, btw, more plants are getting bred for it. Not to mention tasty veggies that allow you to retire your salt shaker

tl;dr: Wat mutt, dat mutt. Imagine Sisyphus happy.