Tonight BBC2 9pm, perhaps giving the answer, sink-hole, underground salt migtation or airbourne salt and concrete reinforcement corrossion?
On 27/06/2021 12:28, N_Cook wrote:> I don't know what this geology effect is called, but Miami , Florida > would be one of the first regions of the world I'd expect to show it . > I saw a TV prog a month ago, that explained something that had puzzled > me about sea level rise. I think it was the Solomon Islands, why their > islands are fast bcoming uninhabitable but global SLR is only a few > inches in a century. Firstly there are hundreds of islands, so a > statistical thing and some are lower lying than others. Secondly > migrating salination of the soil rapidly (over a life time of a farmer) > makes farming impossible . Similarly perhaps rusting the rebar of > concrete piling and concrete spalling earlier than designed for, ie > designed for freshwater only. > As average sea level rises, the salty ground water migrates inland > disproportionally faster than the vertical rise would suggest. > Not just farmers crops, any vegetation including trees succome to the > rising saline soil conditions, die , and soil cohesion goes, so the next > normal storm washes away that island. > In Florida there is ground subsidence due to excessive freshwater > abstraction for agriculture etc. So instead of the global sea level rise > of about 4mm/year, locally to Miami it is about 8mm/year due to the > about equal yearly amount of aquifer depletion and subsidence of the > land above it. > Background to the Florida aquifer problem. >