Communities 'could be abandoned' as seas rise
11 February 2014 Last updated at 11:48 GMT
An investigation by BBC Wales has found that around 50 coastal communities might have to face some form of "managed retreat" from the sea or be abandoned in future, according to plans which have been adopted by local councils.
The plans have been drawn up with expert advice from specialist engineers and hydrologists, and have been adopted by councils, who currently have to maintain sea defences.
One of those communities is Fairbourne in Gwynedd, where a council management plan has concluded there should be no new or improved defences after 2025.
Mike Phillips, professor of coastal geomorphology at the University of Wales Trinity St David's, said if this went ahead decisions would have to be made about whether to move homes or demolish them, and how far inland to go.
"We have built on the coastline, all our activities are on the coastline and that's the area under threat," he told BBC Radio Wales.
He was speaking to Oliver Hides.
A Week In Week Out programme on the subject will be screened on Tuesday, 11 February at 22:35 GMT on BBC One Wales.