Will climate change make shipwrecks pollute the sea?

As oceans warm, species migrate. If these are marine boring organisms – which eat or bore holes through wood – then shipwrecks may degrade faster, he said.

“Then there’s the ongoing process of ocean acidification [where the ocean absorbs more carbon dioxide from the atmosphere when there is an abundance].

“A little change in pH [how acidic or alkaline a solution is] can cause metal, for example, to degrade at a greater rate.”

“Every single wreck is unique, it has a story and people who were on it – sometimes are still on it in terms of human remains,” he said.

“When one of those sites is destroyed, that’s it. It’s gone. You can’t regenerate a shipwreck.”

He said many of the wrecks in Welsh waters were from both world wars, with some having run on coal, and others on oil.

“If they suddenly collapse because they’ve undergone really bad structural degradation, you could have the equivalent of a small oil tanker running aground in terms of the release of oil.”

To mitigate this environmental risk, researchers first have to know what each ship was fuelled on and was carrying.

But there is a problem: the true identities of all the wrecks are not known.