Good question.
Obviously, I think we need to protect the area
, but if and when sea levels rise, the average high tide could require frequent use of higher levels of defence. Our tidal barrier has been used more frequently than when it first was built, but also, the EA has also adopted "controlled retreat" policies, where large tracks of land have been left to the estuary to flood at high tides.
This has meant improvements in the flood management, but ultimately, if levels rise too high we may end up with inter-tidal mud flats that are much bigger than currently. Whether they will surround Hull, I think is unlikely, as surrounding villages close to the Hull boundary will need to be protected. On the West side, this results in a slight rise in land level in the suburbs, so poses less of a risk from the Humber. On the East, we have a flatter geography, and it is only here that the tide has any chance of making any long term advances like you speak of, if left unprotected.
We could end up like Holland, with large sea defences, protecting valuable land. Indeed, with property prices and a feeling of high population density, it may be felt that such schemes may be worthwhile.
If current attitudes are anything to go by, controlled retreat could be the way forward, with us deciding which land is worth saving. IMHO, most of it is
