as much ocean-front real estate is created by sea-level rise as is destroyed, approximately.
There isn't a substantial change in the amount of ocean-front real estate, but there is a substantial change in the total amount of real estate. Super-crude model: you have a square island of side 1 unit; rising sea level reduces the side by 0.01 units of length, which by coincidence is also how near the sea something needs to be to be "ocean-front". Before, the total amount of land is 1 unit and the total amount of sea-front land is 0.0396 units. After, the total amount of land is 0.9801 units and the total amount of sea-front land is 0.0392 units. So the total amount has gone down by ~2x as much relatively, and by ~50x as much in absolute terms.
Cool idea using numbers!
From wikipedia we see that a 1% decrease in above sea level land area happens with about a 10 m sea level rise. In your example above you work with a 2% decrease in area, so you are developing numbers associated with a 20 m rise in sea level.
Predictions are for 0.2 to 0.6 m sea level rise in 100 years. This causes a 0.02% to 0.06% reduction in land area, associated with a 0.01% to 0.03% reduction in coastline.
Note: Please see this post of mine for more on the project, my sources, and potential sources for bias.
I have written a couple of blog posts on my understanding of climate forecasting, climate change, and the Anthropogenic Global Warming (AGW) hypothesis (here and here). I also laid down the sources I was using to inform myself here.
I think one question that a number of readers may have had is: given my lack of knowledge (and unwillingness to undertake extensive study) of the subject, why am I investigating it at all, rather than relying on the expert consensus, as documented by the IPCC that, even if we're not sure is correct, is still the best bet humanity has for getting things right? I intend to elaborate on the reasons for taking a closer look at the matter, while still refraining from making the study of atmospheric science a full-time goal, in a future post.
Right now, I'm curious to hear how you formed your views on climate change. In particular, I'm interested in answers to questions such as these (not necessarily answers to all of them, or even to only these questions).