And when the Siberians walked to North America they did it on dry land. We know that sea level, for example, has risen and fallen hundreds of feet just in the last 15,000 years or so.

At some point, who gives a rat's rump what the cause is. How much land is going to lost (at least for the short term) with a few foot rise? You can argue all millennium about the causes but when the water comes in the front door something needs to be done.

Anybody with functional eyes can see the decline in snow and ice cap on the Cascades and Rockies. That glacial ice is where local summer water comes from. What plans are being made for declining glacial sources of water supplies?

By being more concerned with the cause than the effect we do nothing.