Do you happen to know the elevation of his house?
Nearest I can find, some sources say 9 feet above sea level and others say 10’.
The Obama's is 3 to 4 meters above sea level.
3 meters is between 9' & 10' (9'10" & a whisker) & jives with the elevation map above that says 10'. I'm assuming it's in the yellow zone (flood danger) due to storm surges. I'm not saying that storm surges are getting worse or better, but simply that they are a thing that exists that would potentially explain why this property is in yellow on the flood risk map above.
Then you agree it's rising.
That's all I've stated here.
Currently rising about an inch per decade but has accelerated slightly since 1930.
The more the oceans absorb heat and as land ice melts it could rise faster.
Sea level continues to rise at a rate of about one-eighth of an inch per year. Higher sea levels mean that deadly and destructive storm surges push farther inland than they once did, which also means more frequent nuisance flooding.
What did they use before satellites? When does the "satellite era" begin?
Are the thousands of tide gauges around the globe broken?
Try using Ft Denison's tide guage Oldest in the S Hemisphere
You have less than 100 years out of 3.8 Billion. Narrow it down a little, what is the Holocene mean.
Whittle it down further to the 1000 year mean.
If you want to talk geological processes use geological time.
Why would you limit it to post coldest point in the Holocene?
You need to compare it to thousands of years to average it out to declare acceleration.
27 years is bupkis.