4 ms·

Considering that sea levels were hundreds of feet lower back then, and waterways were critical for both transit and food gathering, it is likely that much of th

Considering that sea levels were hundreds of feet lower back then, and waterways were critical for both transit and food gathering, it is likely that much of the record of human pre-history from this era has been obliterated. Always glad to see discoveries like this that help shed more light on our distant past.

jvm___ 4y ago
What cities will survive in 2300. Atlanta? What's the biggest city that's unlikely to be underwater? What places of our modern storytelling will be just a memory in 2300.
- StanislavPetrov 4y ago
  >What cities will survive in 2300. That all depends on whether or not we avoid nuclear annihilation, which is a risk ancient people did not face. In the age of air travel and superhighways, human beings are much less reliant on waterways than they were in the past (though we are still reliant on them). >What's the biggest city that's unlikely to be underwater? Dallas, Phoenix, Denver? Hard to say which will be larger in 2300.
- spaceman_2020 4y ago
  New Delhi. Population over 32M. Nearest ocean is 900km away.
  - dragonwriter 4y ago
    Distance fron ocean is probable less important than elevation, but 216m seems pretty safe (not Bogota or Mexico City safe, but those are somewhat smaller cities, though not that much in the case of Mexico City.)
dredmorbius 4y ago
The realisation that sea level rises have likely obscured both the paths early humans took into the Americas and their early settlements only occurred to me recently. Though yes, it does seem highly likely. It does make me wonder what if any relics may remain beneath the waves. Inland river valleys are the next most likely sites for early habitations and migrations. Such as this one. In more populated regions, those are all but certainly obliterated by subsequent habitation and construction. Sea levels 30--15 kya would have been 120--100m below present levels. Along the west coast of North America, the continental shelf drops of relatively quickly, but this would still leave a coastal plane several mile seaward of present, and some features such as the Channel Islands would have been far nearer, or even attached to, the mainland. <https://upload.wikimedia.org/wikipedia/commons/1/1d/Post-Glacial_Sea_Level.png https://upload.wikimedia.org/wikipedia/commons/1/1d/Post-Gla...> Looking at that graph, the first thought that occurs is that civilisation emerged largely as the sea-level rise stopped. Why that is I don't know. Globally, the Earth would have appeared about like this: <https://en.wikipedia.org/wiki/Past_sea_level#/media/File:Global_sea_levels_during_the_last_Ice_Age.jpg https://en.wikipedia.org/wiki/Past_sea_level#/media/File:Glo...> I'd like to see details of the western North American coastline reconstructed. I suspect that the San Francisco Bay would have been a low inland plain with rivers running through it (the Sacramento river from the east, and likely the precursor of Coyote Creek from the south). The link below seems to confirm this --- apparently 20 kya the shoreline would have been at what is now the Farallon Islands, now 30 miles (50 km) offshore. <https://historicalmarkerproject.com/markers/HM1QWY_20-000-years-ago_San-Francisco-CA.html https://historicalmarkerproject.com/markers/HM1QWY_20-000-ye...> A KQED bit on evolution of the bay: <https://www.kqed.org/quest/7788/the-importance-of-studying-the-history-of-sea-level-change-in-san-francisco-bay https://www.kqed.org/quest/7788/the-importance-of-studying-t...> SF Bay shoreline evolution: <https://ucmp.berkeley.edu/ucmp_oldsite_nonwpfiles/museum/events/shortcourse2002/images/sloan4.jpg https://ucmp.berkeley.edu/ucmp_oldsite_nonwpfiles/museum/eve...> Peak-glaciation coastline & bay: <https://ucmp.berkeley.edu/ucmp_oldsite_nonwpfiles/museum/events/shortcourse2002/images/sloan2.jpg https://ucmp.berkeley.edu/ucmp_oldsite_nonwpfiles/museum/eve...> Both above from: <https://ucmp.berkeley.edu/ucmp_oldsite_nonwpfiles/museum/events/shortcourse2002/doris.htm https://ucmp.berkeley.edu/ucmp_oldsite_nonwpfiles/museum/eve...> If you go back 125kya, sea levels were higher, and there was a straight between the Bay and Pacific through Colma: <https://cdn.kqed.org/wp-content/uploads/sites/39/2013/01/sanbrunomtn-bay125ka.gif https://cdn.kqed.org/wp-content/uploads/sites/39/2013/01/san...> From: <https://www.kqed.org/quest/49030/geological-outings-around-the-bay-san-bruno-mountain https://www.kqed.org/quest/49030/geological-outings-around-t...> California in the Late Pleistoscene (18 kya), with a fully-glaciated Sierra, many intermountain lakes especially on the east side of the Sierra Nevada, central-valley lakes, and a coastline extended far westward: <https://www.secretmuseum.net/map-of-lower-california/ https://www.secretmuseum.net/map-of-lower-california/>
- AlotOfReading 4y ago
  UCSB has an informational page about the former bay area coastline [1]. In general, we have excellent models of the late Pleistocene coastline changes for most of the west coast and the ease of access from major universities means there's been a lot of surveying, especially in places like the channel islands. Our understanding of the first settlers is immensely better than our understanding of their immediate ancestors because we've found so little in Siberia/Alaska/Northeast Asia. One of the big issues holding back progress has been the difficulty of improving the glaciation model resolution, which has become increasingly important as the evidence builds that humans entered the new world pretty much as soon as it was possible rather than waiting for conditions to be "easy" (read: still incredibly hostile). [1] https://animations.geol.ucsb.edu/2_infopgs/IP2IceAge/cSFBayFlood.html https://animations.geol.ucsb.edu/2_infopgs/IP2IceAge/cSFBayF...
  - dredmorbius 4y ago
    Thanks! The first thing that jumps out at me on that animation is that the Bay shrank over the past 2000 years. I'm wondering why that was --- sedimentation and wetlands filling in the Bay, falling sea levels, or ... ? Really interesting to watch, though, appreciated.
- moloch-hai 4y ago
  We know people in southeast Asia 70,000 years ago had boats they deliberately sailed out of sight of land: they colonized Australia. (Maybe via Timor, maybe Sulawesi, maybe both.) That they would have sailed wherever else they could, including along the Aleutians to North America, is the null hypothesis: you would need to demonstrate that they didn't, and show why not. The region had a million square miles of bottom land now under the sea. People lived there for tens of millennia, and were driven by sea level rise, generation by generation, to high ground where other people already lived. Something dramatic happened much more recently such that much of the population of the region now traces ancestry to a mother population from Taiwan. Plague, maybe? Another puzzle.
- spaceman_2020 4y ago
  > the first thought that occurs is that civilisation emerged largely as the sea-level rise stopped. The more likely explanation is that we only have records of civilization that survived the sea water rise. Graham Hancock can get into soe kooky territories, but he has some interesting ideas on civilization during the ice age.

jvm___ 4y ago

What cities will survive in 2300. Atlanta? What's the biggest city that's unlikely to be underwater? What places of our modern storytelling will be just a memory in 2300.

StanislavPetrov 4y ago
>What cities will survive in 2300. That all depends on whether or not we avoid nuclear annihilation, which is a risk ancient people did not face. In the age of air travel and superhighways, human beings are much less reliant on waterways than they were in the past (though we are still reliant on them). >What's the biggest city that's unlikely to be underwater? Dallas, Phoenix, Denver? Hard to say which will be larger in 2300.
spaceman_2020 4y ago
New Delhi. Population over 32M. Nearest ocean is 900km away.
- dragonwriter 4y ago
  Distance fron ocean is probable less important than elevation, but 216m seems pretty safe (not Bogota or Mexico City safe, but those are somewhat smaller cities, though not that much in the case of Mexico City.)

dredmorbius 4y ago

The realisation that sea level rises have likely obscured both the paths early humans took into the Americas and their early settlements only occurred to me recently. Though yes, it does seem highly likely. It does make me wonder what if any relics may remain beneath the waves. Inland river valleys are the next most likely sites for early habitations and migrations. Such as this one. In more populated regions, those are all but certainly obliterated by subsequent habitation and construction. Sea levels 30--15 kya would have been 120--100m below present levels. Along the west coast of North America, the continental shelf drops of relatively quickly, but this would still leave a coastal plane several mile seaward of present, and some features such as the Channel Islands would have been far nearer, or even attached to, the mainland. <https://upload.wikimedia.org/wikipedia/commons/1/1d/Post-Glacial_Sea_Level.png https://upload.wikimedia.org/wikipedia/commons/1/1d/Post-Gla...> Looking at that graph, the first thought that occurs is that civilisation emerged largely as the sea-level rise stopped. Why that is I don't know. Globally, the Earth would have appeared about like this: <https://en.wikipedia.org/wiki/Past_sea_level#/media/File:Global_sea_levels_during_the_last_Ice_Age.jpg https://en.wikipedia.org/wiki/Past_sea_level#/media/File:Glo...> I'd like to see details of the western North American coastline reconstructed. I suspect that the San Francisco Bay would have been a low inland plain with rivers running through it (the Sacramento river from the east, and likely the precursor of Coyote Creek from the south). The link below seems to confirm this --- apparently 20 kya the shoreline would have been at what is now the Farallon Islands, now 30 miles (50 km) offshore. <https://historicalmarkerproject.com/markers/HM1QWY_20-000-years-ago_San-Francisco-CA.html https://historicalmarkerproject.com/markers/HM1QWY_20-000-ye...> A KQED bit on evolution of the bay: <https://www.kqed.org/quest/7788/the-importance-of-studying-the-history-of-sea-level-change-in-san-francisco-bay https://www.kqed.org/quest/7788/the-importance-of-studying-t...> SF Bay shoreline evolution: <https://ucmp.berkeley.edu/ucmp_oldsite_nonwpfiles/museum/events/shortcourse2002/images/sloan4.jpg https://ucmp.berkeley.edu/ucmp_oldsite_nonwpfiles/museum/eve...> Peak-glaciation coastline & bay: <https://ucmp.berkeley.edu/ucmp_oldsite_nonwpfiles/museum/events/shortcourse2002/images/sloan2.jpg https://ucmp.berkeley.edu/ucmp_oldsite_nonwpfiles/museum/eve...> Both above from: <https://ucmp.berkeley.edu/ucmp_oldsite_nonwpfiles/museum/events/shortcourse2002/doris.htm https://ucmp.berkeley.edu/ucmp_oldsite_nonwpfiles/museum/eve...> If you go back 125kya, sea levels were higher, and there was a straight between the Bay and Pacific through Colma: <https://cdn.kqed.org/wp-content/uploads/sites/39/2013/01/sanbrunomtn-bay125ka.gif https://cdn.kqed.org/wp-content/uploads/sites/39/2013/01/san...> From: <https://www.kqed.org/quest/49030/geological-outings-around-the-bay-san-bruno-mountain https://www.kqed.org/quest/49030/geological-outings-around-t...> California in the Late Pleistoscene (18 kya), with a fully-glaciated Sierra, many intermountain lakes especially on the east side of the Sierra Nevada, central-valley lakes, and a coastline extended far westward: <https://www.secretmuseum.net/map-of-lower-california/ https://www.secretmuseum.net/map-of-lower-california/>

AlotOfReading 4y ago
UCSB has an informational page about the former bay area coastline [1]. In general, we have excellent models of the late Pleistocene coastline changes for most of the west coast and the ease of access from major universities means there's been a lot of surveying, especially in places like the channel islands. Our understanding of the first settlers is immensely better than our understanding of their immediate ancestors because we've found so little in Siberia/Alaska/Northeast Asia. One of the big issues holding back progress has been the difficulty of improving the glaciation model resolution, which has become increasingly important as the evidence builds that humans entered the new world pretty much as soon as it was possible rather than waiting for conditions to be "easy" (read: still incredibly hostile). [1] https://animations.geol.ucsb.edu/2_infopgs/IP2IceAge/cSFBayFlood.html https://animations.geol.ucsb.edu/2_infopgs/IP2IceAge/cSFBayF...
- dredmorbius 4y ago
  Thanks! The first thing that jumps out at me on that animation is that the Bay shrank over the past 2000 years. I'm wondering why that was --- sedimentation and wetlands filling in the Bay, falling sea levels, or ... ? Really interesting to watch, though, appreciated.
moloch-hai 4y ago
We know people in southeast Asia 70,000 years ago had boats they deliberately sailed out of sight of land: they colonized Australia. (Maybe via Timor, maybe Sulawesi, maybe both.) That they would have sailed wherever else they could, including along the Aleutians to North America, is the null hypothesis: you would need to demonstrate that they didn't, and show why not. The region had a million square miles of bottom land now under the sea. People lived there for tens of millennia, and were driven by sea level rise, generation by generation, to high ground where other people already lived. Something dramatic happened much more recently such that much of the population of the region now traces ancestry to a mother population from Taiwan. Plague, maybe? Another puzzle.
spaceman_2020 4y ago
> the first thought that occurs is that civilisation emerged largely as the sea-level rise stopped. The more likely explanation is that we only have records of civilization that survived the sea water rise. Graham Hancock can get into soe kooky territories, but he has some interesting ideas on civilization during the ice age.