I'm not a climatologist, but rising sea levels are not the only problem. They are simply the most commonly selected problem to cite, as 'submerged cities' strikes close to home, and is a classical apocalyptic (and thus greatly feared) event.
There are far more consequences than just that. For example, all the coral of the entire ocean would be dead or dying. Not that I expect you to care about coral; that is just one example.
There are far more consequences than just that. For example, all the coral of the entire ocean would be dead or dying. Not that I expect you to care about coral; that is just one example.