A lot more details here including how the sea wall dates back to 1795.
http://dublinportblog.com/2013/10/the-great-south-wall-poolbeg-lighthouse/
I found this bit interesting, and of course, no-one seems to use that reference mark now...
Historically, the Ordnance Survey Ireland used the low water mark of the spring tide on the 8th April 1837 at the Poolbeg Lighthouse as a standard height for all its maps, a practice which continued up until 1958.
When we were at the James Joyce tower south of Dublin, we were in the middle of a major squall. Water was spraying high into the air up over the cliff, and the tower is on a fairly high cliff. They have some major storms in and around there. Nothing to do with globull warming.