Climate change brings with it the inevitability of rising sea levels. Even if green house gas emissions were stopped completely, the sea will continue to rise for hundreds or thousands of years.
Not only will the submerged properties be affected by the rising tides, so will all the new island properties. Initially, some properties will just be temporarily cut-off from civilization. Eventually, those temporary islands will become permanent.
An initial reaction may be "Oh, I've always wanted to live on island;" however, being stranded on a deserted island is not fun. It is important to look forward and evaluate the risk in value to real estate. Much of the newly isolated land will become worthless.
ARS Technica reports, "having a property above water won't be much good if flooding nearby means you can't get to a hospital or grocery store when you need to or lose access to electricity or other services. It's entirely possible for rising seas to leave a property high, dry, but uninhabitable as rising seas cut connections to essential services. A group of researchers has analyzed the risk of isolation driven by sea level rise, and shows it's a major contributor to the future risks the US faces."
If you're interested in comparing the risk of isolation to that of inundation, the researchers built a website that lets you explore the risks under different sea level rise scenarios.
The Journal Nature published "Risk of isolation increases the expected burden from sea-level rise":
The typical displacement metric for sea-level rise adaptation planning is property inundation. However, this metric may underestimate risk as it does not fully capture the wider cascading or indirect effects of sea-level rise. To address this, we propose complementing it by considering the risk of population isolation: those who may be cut off from essential services. We investigate the importance of this metric by comparing the number of people at risk from inundation to the number of people at risk from isolation. Considering inundated roadways during mean higher high water tides in the coastal United States shows, although highly spatially variable, that the increase across the United States varies between 30% and 90% and is several times higher in some states. We find that risk of isolation may occur decades sooner than risk of inundation. Both risk metrics provide critical information for evaluating adaptation options and giving priority to support for at-risk communities.