The dykes needed would require massive civil engineering projects and expensive pumps as mentioned in OA (the bit about New Orleans). That needs coordination at

The dykes needed would require massive civil engineering projects and expensive pumps as mentioned in OA (the bit about New Orleans). That needs coordination at a regional level and I gather from the OA that the required consensus does not exist. I think you have a point in the sense that building a consensus may require a tacit agreement not to mention global warming, but simply to look at the frequency of flooding in specific areas (which will show a rise) and the inland creep of the 'potable water contour'. I'm saying agree about the phenomena and agree to disagree about the cause.