The former plane that is now the southern North Sea floor is generally known as Doggerland after the Dogger Bank. The Dogger Bank was once a mountain in this plane, then an island in the North Sea. Today it is a shallow area in the North Sea that is important because it is dangerous for shipping. It is named after the doggers, a Dutch type of fishing boats. The nets of these boats often scrape the North Sea floor and have been the source of interesting finds from various eras when the North Sea floor was dry. The last one was during and around the last Ice Age.
The following map shows a part of Europe centered around the North Sea:
https://ancillary-proxy.atarimworker.io?url=https%3A%2F%2Fcommons.wikimedia.org%2F...
- On the left today's situation.
- On the right the situation during the last Ice Age, when all of the British Isles and Scandinavia were covered by ice and France and Central Europe were comparable to today's Siberia. Only the most southern parts of Europe had appreciable human populations.
- In the middle the situation at the time when the Doggerland plane still existed and was already warm enough to be suitable for extensive human habitation by hunter-gatherers. This was roughly from 16000 BCE till 7000 BCE, although the last remnant of Doggerland, in the shape of an island where we now have the Dogger Bank, didn't disappear before around 5500 BCE.
The period depicted in the middle of the map is what the original article / news story is about. We are talking about the time when Britain and Ireland were last (not for the first time!) transformed from a single peninsula into two big islands and the Rhine-Thames river became the English Channel separating Britain from France.
Similar things happened elsewhere in the world at the same time. The world at the time of the Last Glacial Maximum (the height of the last Ice Age) can be seen on this map: https://ancillary-proxy.atarimworker.io?url=https%3A%2F%2Fcommons.wikimedia.org%2F... . Notably, the area around Indonesia was a huge peninsula -- a subcontinent of Asia much larger than the Indian subcontinent. Just like Britain, Indonesia was turned from part of a huge peninsula into an island.
The global sea level rise can be seen on this graph: https://ancillary-proxy.atarimworker.io?url=https%3A%2F%2Fcommons.wikimedia.org%2F... . Note that the horizontal axis is labelled in 1000 years ago, not in years BCE, so the Doggerland period is in the range from 18 to 9 on the map, and the catastrophe that flooded the Dogger Bank island was near 7.5 -- at a point when sea levels were beginning to stabilise almost on today's level. As far as I know, global sea level changes alone do not fully explain what happened to Doggerland. If I remember correctly, the current theory is that in the relevant period the still massive Scandinavian ice shelf depressed the Scandinavian land mass by several metres, and that this made Doggerland rise a few metres. (Recall that the continents are floating on magma.)
I think nothing is known about the genetics of the hunter-gatherers of Doggerland yet, because no human bones have been found yet. We do however know that the earliest humans who left significant genetic traces in today's population were the Western Hunter-Gatherers. They were 'black'-skinned and blue-eyed and are responsible for roughly a third of the ancestry of today's Europeans. It seems natural to speculate that the inhabitants of Doggerland belonged to this group. (Since 'black' skin is a specific adaptation for the tropics that our earliest human ancestors in Africa developed when losing their fur, it was relatively easy for evoluton to return Europeans to 'white' skin, which is more advantageous in northern regions. This is about trade-offs betwen skin cancer prevention and vitamin production in the winter.) Many people in the Baltics have almost exclusively Western Hunter-Gatherer ancestry, so apart from skin colour they might be most similar to the Doggerlanders.
There is speculation that the flood myths that can be found world-wide are somehow related to the flooding of large inhabited land masses in general and the one around Indonesia in particular, that the spread of agriculture starting simultaneously in various centres arranged almost like a wreath around Indonesia was caused by refugees from that region, and that the Atlantis myth is really about the Dogger Bank island. We may never know, but I think these speculations are fun. No doubt they will soon begin to appear in literature and popular culture.
It is also interesting to note that as late as 2000 years ago, when the Romans under Julius Caesar reached the North Sea region, they reported that there was basically no difference between Belgian and British tribes. Both regions had several different tribes that spoke different languages, but apparently the major tribes existed both on the continent and in Britain. It sounds almost as if at that time, 5500 years after the flooding of the Dogger Bank island, the descendants of the Doggerlanders still had a common cross-North-Sea culture.
The last time Doggerland made it into the general media was in 2007, when a huge project to map the southern North Sea floor and translate it into a map of Doggerland culminated in this book: https://ancillary-proxy.atarimworker.io?url=https%3A%2F%2Fwww.amazon.co.uk%2Fdp%2F19... . Since then, numerous documentaries have been made that you can easily find on YouTube by searching for "Doggerland". "Britain's Lost World" is one of the early and good ones. A good introduction with many pointers to scholarly literature is of course the Wikipedia article: https://ancillary-proxy.atarimworker.io?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2F... .