An interesting story, as many such stories are from all ancient cultures, but it clearly is not what actually happened.
And certainly there will be elements of such stories that bare some relationship to reality.
Evidence is now clear that sea levels varied substantially over time, and that the last 8,000 years of relatively stable sea level is the exception rather than the rule, so that just 10,000 years ago it would have been possible to walk to Sri Lanka from India, and that would have been so for 30,000 years. 20,000 years ago sea level was almost 500ft (140m) below where it is now, meaning in most places the coast was many miles from its current position, and one could walk from Asia to North America.
So stories of great floods all over the world are true in a sense. In the sense that all the coastal communities of 20,000 years ago are now under at least 400ft of water. And most of evidence of them has been completely destroyed by centuries of wave action as the seas gradually rose (at about 3 ft every 100 years, for 12,000 years) – with occasional spurts where it may have come up as much as a foot every 5 years.
So it is not at all surprising that there are world wide myths of global floods, for in a very real sense, that is what happened, repeatedly, many times over the last 2 million years.
It is also true that there are sometimes winters that last for many years – due to very large volcanoes.
So the earth is not a benign thing.
It is not a stable thing.
It is not something that cares for us.
It is a very complex set of systems, that sometimes produces outcomes that are very difficult to survive, and the last 8,000 years of relative stability are very much the exception to the rule.
If we wish to have security, then we need to develop some serious technology very quickly.
We also need to develop systems of global cooperation to match the technologies.
We cannot look to the past alone for guidance.
We seem to have the capacity to create systems that are highly cooperative, and we also have the ability to be highly competitive.
As the old shaman story of the two wolves within us goes:
Which wolf wins – the one we feed.
We have been feeding the competitive wolf with our economic structures for too long – it is now a very dangerous beast.
Our focus must be on feeding the cooperative wolf!