[yesthatjallen]

According to Wikiepdia the elevation of Portsmouth is 20 ft (6 m).

According to an article from Live Science:

"The 2 meters by 2100 is cited a lot, but if you ask scientists what they think of that number, they say it is probably a little high, maybe 1.5 meters [4.9 feet] is more like an upper bound," Willis said.

https://www.livescience.com/39891-sea-level-rise-ipcc-report.html

[palmer]

"The 2 meters by 2100 is cited a lot, but if you ask scientists what they think of that number, they say it is probably a little high, maybe 1.5 meters [4.9 feet] is more like an upper bound," Willis said.

Current sea level rise is about a little over an inch per decade. It is not accelerating. The chances of attaining that kind of rise (7.5 inches per decade) is zero. Furthermore while the worldwide average might be as much as 3mm per year, the relative rise in Portsmouth is just 1-2mm per year as others posted.