[revelio]

Please prove that it's human actions that cause coastal erosion, because I'm pretty sure coastlines have always been moving and shifting in response to erosion. That's how beaches are made, isn't it?

Also, even if that were to be true which I doubt, so what? They were supposed to sink beneath the waters as they rapidly rise due to melting polar ice. That was the doom scenario that was used to motivate people, but it hasn't happened. In a rational world that should cause us to toss out the other predictions made by such "experts", not try to retcon what was said to fit whatever actually happens. Especially because a change like "maybe a beach migrates northward a bit in some islands, others grow a bit, others shrink a bit" is nowhere near important enough to make disruptive changes to the lives of everyone on the planet.