A coastline absolutely can vanish(submerged) or be against geography, such as rocky cliffs, that is unsuitable. “Coastlines can’t stop existing, only move” is semantic nonesense.
EDIT: for ya downvoters, where’s the coastline on an island that vanishes due to rising sea levels? The Marshall Islands have a max elevation of ~7’ and are already having issues with rising sea levels. When the sea rises above them, where does their coastal ecosystem go?
A coastline absolutely can vanish(submerged) or be against geography, such as rocky cliffs, that is unsuitable. “Coastlines can’t stop existing, only move” is semantic nonesense.
EDIT: for ya downvoters, where’s the coastline on an island that vanishes due to rising sea levels? The Marshall Islands have a max elevation of ~7’ and are already having issues with rising sea levels. When the sea rises above them, where does their coastal ecosystem go?