Climate resilience construction is a good thing, regardless of whether sea levels are rising or not...
The NYC subway flooded already... The tunnels below the Hudson are vulnerable already... bridges are in danger already. People died and will continue dying unless changes are made.
Spending money on measures to protect vital infrastructure is a good thing whether or not you agree with rising waters due to climate change.
Reality is most engineers are not as dumb as we may look. There is a list of standards to be considered in designing for water flow and flooding. Usually they are expressed in year intervals of likely occurrence. Like 10, 25, 50, 100 year interval. Usually you don't go beyond 100 because reality is that you don't have enough money to do everything. Reality is that designing for a 100 year storm does not mean that it will only occur once in 100 years. It means that every year you have a 1% change of having a storm of that intensity. As an example, quite a few years ago, in the 70's I think, Richmond VA had a 100+ year flood 6 times in 10 years. They have not had any that has gotten anywhere close since. Generally subdivision and other street inlets and storm sewers are designed for 25 year floods, BUT it is also a requirement that overflows not impact buildings. Never done that sort of thing, so I cannot say what that overflow design return period is. Generally for major highways it is 50 or 100, but again, that is nominal ditch and culvert and bridge capacity. It does not mean if you exceed it the world ends.
During the period I was in Taiwan the Taiwan Railway had been placed below ground and the first portion of the Mass Rapid Transit system completed. The downtown MRT station on the Red line was below the TRA station. The city / national government was well on its way to completing a set of 500 year storm walls and levees around the city. All that was left was a relatively short section of levees designed to hold back the design 200+ year river flow. And Then:!! We had Typhoon Nari. While most Pacific Typhoons follow a relatively predictable path, this one did not. It made landfall and then stalled. The area covered by the typhoon was almost identical to that of the Keelung River basin which is the river flowing by Taipei city. We had three days of hard rain falling on the entire river basin. The 500 year walls and levees had water quite a ways up them, but were not near to being overtopped. However, the 200 year levees were overtopped. As a result we had 3 to 5 feet of water in many streets and water into the TRA and MRT tunnels. There was a picture taken from the top of one of the escalators to the railway platform that showed about 5 feet of water over the platform, and obviously more over the track. What that really meant was that the MRT station was full to the ceiling. Although there was quite a bit of political uproar, it was ultimately recognized that you cannot protect everything against everything. However, the remaining system of levees to 500 year flooding was completed post haste.
Back to the subject at hand, yes, anything new should be based on the possibility of a two foot seal level rise, but I really consider that overkill. Who knows what the climatic trends will be over the next 100 years. More consideration should be given to storm surges that appears to currently be the case. That consideration should probably appease the 2 foot panic people. What I would do, is for every coastal line along the west coast any section needing rebuilding should be about 25 feet above sea level. This is not for sea level rise, but for tsunamis.
