At https://phys.org/news/2023-05-years-outflow-mediterranean-atlantic-ocean.html … we are told that at the start of the Yonger Dryas episode, around 13,000 years ago, global temperatures plummeted. This appears to coincide with an arid phase around the Mediterranean basin. This is described, in Steven Mithen’s book, After the Ice, but pertains essentially to the Levant, and presumably the eastern Mediterranean. The authors appear to expand this idea to the whole of the Mediterranean basin – which is a very big area. Anyway, the gist of the story is that during the Younger Dryas episode, roughly lasting 1300 years, the flow of water into the Atlantic, via the Straits of Gibraltar, doubled. Yes, twice as much water was being discharged into the Atlantic. The paper then goes on to suggest that this water, with a high saline content, affected the North Atlantic ocean conveyor belt system and eventually caused the modern circulation of the ocean to return to normal. Asuming the current ocean pattern is normal. However, it took 1300 years to accomlish this – and one may wonder if they are producing research in support of the consensus view of the Younger Dryas, and ignoring the catastrophist theory of Firestone et al. Bill Napier has more recently suggested the earth passed through a dense stream of meteors outgassed from a comet, setting the Younger Dryas in motion. This idea must also apply to the Older and Oldest dryas periods as well. The theory involves a very large comet shedding a lot of material and creating, in the process, a complex of meteor streams that continued to cause problems on earth during the Holocene. Not everyone’s cup of tea, and obviously the authors of the study remain silent on the issue.
If the saline properties of the Mediterranean did not affect the North Atlantic circulation then scientists have to find a reason why the outflow was double what it is in the modern world. One idea mooted in recent years is that the Mediterranean was different in the early Holocene – and therefore different at the Younger Dryas boundary. For instance, the Aegean islands were much bigger than they are now, suggesting a sea level rise at some point – during the Holocene. The same goes for the ridge of land, now submerged, between what is now Tunisia and Malta/Sicily. Much of this may have been dry land, just as the North Sea basin was dry. Hence, the incoming Atlantic water would have been turned around more quickly than it is now. No doubt other alternative theories can be produced. One does not have to follow the consensus line on this topic.