You aren't taking into effect erosion. As the rising sea passed a threshold erosion likely exacerbated. Think of water behind a dyke. As soon as a little water trickles over the edge, a small channel will grow quickly. In this case, if it weren't for climate change and the rising sea, the island might have been fine.
Well, accident rates have been dropping steadily for years, so I'd have to think "no."
[Citation Needed] Have fatalities been going down? Is this correlated with more safe automobiles? How about the number of crashes, not just fatalities? How about an age breakdown of drivers involved? Are younger drivers getting in marginally more crashes due to distractions while older, non texting drivers significantly less likely to get in a crash? You need details to support your cause...
If it has syntax, it isn't user friendly.