6 ms·

20,000 years ago the ocean levels were 130 meters lower. Imagine all the coastal settlements that are lost

avdempsey 5y ago
That claim struck me as extraordinary, but sure enough: https://en.m.wikipedia.org/wiki/Past_sea_level https://en.m.wikipedia.org/wiki/Past_sea_level
redis_mlc 5y ago
The North Sea was Doggerland 8500 years ago: https://en.wikipedia.org/wiki/Doggerland https://en.wikipedia.org/wiki/Doggerland You could walk from the Netherlands to Britain. Before that, the Mediterranean Sea was a dry depression. When the Atlantic barrier collapsed, you can imagine the wall of water filling the basin and chasing early humans uphill.
- ncmncm 5y ago
  The Mediterranean has been full throughout human prehistory. Some think the Black Sea was much smaller, and filled up, during the period in question. But evidence there is inconclusive. We know there was a cataclysmic meteor strike toward the west end of the Persian Gulf, well after it had filled in.
  - masklinn 5y ago
    > Some think the Black Sea was much smaller, and filled up, during the period in question. But evidence there is inconclusive. Evidence of catastrophic flooding is debated and inconclusive. That the black sea’s level used to be much lower is not, all water levels were much lower at the glacial maximum, and gradually rose as the ice age ended, nearing stable historical sea levels around 7.5kya (5500 bce).
    - ncmncm 5y ago
      I am corrected: Yes,the Black Sea level was much lower, and rose. But how quickly? E.g., if the Bosporus was blocked, and later broke, the water could rise very quickly, over weeks, not years. It could fall, instead, if the sea had filled in, and then suddenly drained by a similar process. But the subject is complicated by the unknown inflow from rivers, and from meltwater of retreating glacier. Hydrology is complicated.
- jcranmer 5y ago
  The Zanclean Flood (refilling of the Mediterranean) happened about 5 million years ago. That predates not only Homo sapiens sapiens, nor the Homo genus itself, but even Australopithecus itself.
  - deleted 5y ago
    [deleted]
kibwen 5y ago
Not just that. The Persian Gulf, in the heart of the cradle of civilization, is an average of 50m deep, never more than 90m. That's 250,000 square km of prime real estate (a river valley fed by the same rivers that would eventually produce Sumeria) that would have been well above the water line when civilization was just getting started. No wonder every culture has a flood myth.
- mc32 5y ago
  How quickly did coastal areas get reclaimed by the seas? If it happened over centuries then it’s a slow creep and hardly a flood, though given geography, it’s likely some areas got reclaimed at accelerated rates. In any event we’d need some evidence before accepting that this was the genesis of the myths.
  - ch4s3 5y ago
    It seems like somewhere between 1m-5m per century depending on time and place[1]. At 5m that would be noticeable in a lifetime in a coastal estuary, you would see dwellings from your childhood swallowed by the sea by middle age. Interestingly, Sumerian myths said that the Akkadians arrived from the sea and brought with them the knowledge of city building. Certainly begs some interesting questions. [1]https://noc.ac.uk/news/global-sea-level-rise-end-last-ice-age https://noc.ac.uk/news/global-sea-level-rise-end-last-ice-ag...
    - mc32 5y ago
      We need to know how people settled. Was it permanent dwellings, limited-lifespan dwellings (wattle/reed), seasonal dwellings, or nomadic dwellings. If people kind of moved from season to season, or as local resources get depleted, then water creeping up is kind of just accepted as "they way things happen." If it was settled for hundreds of years and then water crept up, sure, I can see that being considered a flood if it happened quickly enough. I guess we may have to live with guesswork as I doubt we'll have convincing answers.
      - 5y ago
sliken 5y ago
A story about similar, for those who haven't seen it: https://xkcd.com/1190/ https://xkcd.com/1190/
ekianjo 5y ago
Not sure there were that many coastal settlements in the first place. Ultimately you need access to drinking water and being next to a river is much better than being next to the sea.
- masklinn 5y ago
  > being next to a river is much better than being next to the sea. You can be next to both. Coastal settlements provide excellent food sources, and greatly limits various health issues (lack of salt, iodine, …). Consuming fish blood would also help, it’s going to be much closer to isotonic than seawater. Depending on land structures, coastal settlements would also often benefit from much higher precipitation rates, providing freshwater. That’s essentially the story of Polynesian settlements, islands would be settled if they either had natural springs or enough precipitations.
- hutzlibu 5y ago
  Thats why those settlements are usually all located on a river that goes into the the sea. (but for actual drinking water, smaller springs are preferrerd and can be found almost everywhere, except the dessert, too) So you have drinking water - and can do extensive fishing, in the river as well in the sea - and in the very fish rich area in between. Also with a river you can more easily connect inland. (have you never played civilisation?)

That claim struck me as extraordinary, but sure enough: https://en.m.wikipedia.org/wiki/Past_sea_level https://en.m.wikipedia.org/wiki/Past_sea_level

redis_mlc 5y ago

The North Sea was Doggerland 8500 years ago: https://en.wikipedia.org/wiki/Doggerland https://en.wikipedia.org/wiki/Doggerland You could walk from the Netherlands to Britain. Before that, the Mediterranean Sea was a dry depression. When the Atlantic barrier collapsed, you can imagine the wall of water filling the basin and chasing early humans uphill.

ncmncm 5y ago
The Mediterranean has been full throughout human prehistory. Some think the Black Sea was much smaller, and filled up, during the period in question. But evidence there is inconclusive. We know there was a cataclysmic meteor strike toward the west end of the Persian Gulf, well after it had filled in.
- masklinn 5y ago
  > Some think the Black Sea was much smaller, and filled up, during the period in question. But evidence there is inconclusive. Evidence of catastrophic flooding is debated and inconclusive. That the black sea’s level used to be much lower is not, all water levels were much lower at the glacial maximum, and gradually rose as the ice age ended, nearing stable historical sea levels around 7.5kya (5500 bce).
  - ncmncm 5y ago
    I am corrected: Yes,the Black Sea level was much lower, and rose. But how quickly? E.g., if the Bosporus was blocked, and later broke, the water could rise very quickly, over weeks, not years. It could fall, instead, if the sea had filled in, and then suddenly drained by a similar process. But the subject is complicated by the unknown inflow from rivers, and from meltwater of retreating glacier. Hydrology is complicated.
jcranmer 5y ago
The Zanclean Flood (refilling of the Mediterranean) happened about 5 million years ago. That predates not only Homo sapiens sapiens, nor the Homo genus itself, but even Australopithecus itself.
- deleted 5y ago
  [deleted]

kibwen 5y ago

Not just that. The Persian Gulf, in the heart of the cradle of civilization, is an average of 50m deep, never more than 90m. That's 250,000 square km of prime real estate (a river valley fed by the same rivers that would eventually produce Sumeria) that would have been well above the water line when civilization was just getting started. No wonder every culture has a flood myth.

mc32 5y ago
How quickly did coastal areas get reclaimed by the seas? If it happened over centuries then it’s a slow creep and hardly a flood, though given geography, it’s likely some areas got reclaimed at accelerated rates. In any event we’d need some evidence before accepting that this was the genesis of the myths.
- ch4s3 5y ago
  It seems like somewhere between 1m-5m per century depending on time and place[1]. At 5m that would be noticeable in a lifetime in a coastal estuary, you would see dwellings from your childhood swallowed by the sea by middle age. Interestingly, Sumerian myths said that the Akkadians arrived from the sea and brought with them the knowledge of city building. Certainly begs some interesting questions. [1]https://noc.ac.uk/news/global-sea-level-rise-end-last-ice-age https://noc.ac.uk/news/global-sea-level-rise-end-last-ice-ag...
  - mc32 5y ago
    We need to know how people settled. Was it permanent dwellings, limited-lifespan dwellings (wattle/reed), seasonal dwellings, or nomadic dwellings. If people kind of moved from season to season, or as local resources get depleted, then water creeping up is kind of just accepted as "they way things happen." If it was settled for hundreds of years and then water crept up, sure, I can see that being considered a flood if it happened quickly enough. I guess we may have to live with guesswork as I doubt we'll have convincing answers.
    - 5y ago

sliken 5y ago

A story about similar, for those who haven't seen it: https://xkcd.com/1190/ https://xkcd.com/1190/

ekianjo 5y ago

Not sure there were that many coastal settlements in the first place. Ultimately you need access to drinking water and being next to a river is much better than being next to the sea.

masklinn 5y ago
> being next to a river is much better than being next to the sea. You can be next to both. Coastal settlements provide excellent food sources, and greatly limits various health issues (lack of salt, iodine, …). Consuming fish blood would also help, it’s going to be much closer to isotonic than seawater. Depending on land structures, coastal settlements would also often benefit from much higher precipitation rates, providing freshwater. That’s essentially the story of Polynesian settlements, islands would be settled if they either had natural springs or enough precipitations.
hutzlibu 5y ago
Thats why those settlements are usually all located on a river that goes into the the sea. (but for actual drinking water, smaller springs are preferrerd and can be found almost everywhere, except the dessert, too) So you have drinking water - and can do extensive fishing, in the river as well in the sea - and in the very fish rich area in between. Also with a river you can more easily connect inland. (have you never played civilisation?)