The older seaports are the more vulnerable to SLC because, as these graphs generally show, sea level tends to be at a different level now compared to when the seaports were built.
I have marked the ends of those records with a small blue square.
Another seaport complication is that there are two types of SLC, sea level fall (SLF) and sea level rise (SLR).
The graph at Fig. 3 shows a case of SLF, the graph at Fig. 11 shows a mixed case of both, while the other graphs tend to show cases of SLR.
Remember that infrastructure around seaports will be more exposed in older ports than they will be in newer ports, whether they face SLR or they face SLF.
It can undermine infrastructure unexpectedly that way.
When flora begin to die out from being exposed to salt water, the infrastructure can also soon be subjected to damage from incursion.
This happens well before the seawater actually breaches the surface of the land (flooding) which that infrastructure is built upon (The Extinction of Charleston, The Extinction of Philadelphia, The Extinction of Washington, D.C., The Extinction of Boston, The Extinction of Miami, The Extinction of Manzanillo,The Extinction of Providence, The Extinction of Chesapeake Bay Islands).
To the contrary, in areas where SLF is taking place, the infrastructure can be isolated as the waters move away from the high tide mark, and as the seaport becomes more shallow.
Marine engineering and construction firms face the problem of determining when and how much SLC will take place well ahead of the time when construction would have to begin in order to be timely (Peak Sea Level - 2).
Add to that the logistics nightmare of all seaports needing attention at relatively the same time.
You know, SLC is taking place on a global scale, rendering thousands of ports vulnerable at about the same time.
There are thousands of ports, but only a relatively small number of competent marine engineering and construction companies available to help the thousands of ports facing increasing vulnerability.
Add to that the political tugs and pulls on public bodies, such as port authorities who have political realities to face, and "Houston we have a problem" (The Extinction of Houston).
Some of those port authorities are climate change deniers who have to deal with the public and higher ups in the federal government.
Most of the federal officials are not climate change deniers (Global Climate & Homeland Insecurity - 2).
In some places the political tug of war will exacerbate the issues, adding even more difficulty to the substantial and still underestimated predicament (Why Sea Level Rise May Be The Greatest Threat To Civilization, 2, 3, 4, 5).
Even one of those difficulties or one port can have a domino effect which affects the viability of other ports "down stream" from the problem or predicament (The top 10 metropolitan port complexes in the U.S.).
The next post in this series is here, the previous post in this series is here.