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Comment by curtis | Hacker News Reader

One of the challenges of North American archaeology is that it's likely that many potential archaeological sites are now underwater, since sea level was about 400 feet lower at the peak of the last ice age.

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I've always felt like if there were other earlier migrations, since they necessarily would need to be coast and seafaring migrations (potentially no bridge or path through the glaciers to southern North America), then by definition all trace of those migrations and settlements would be almost entirely be lost because they are coastal cultures, at least initially. 400 feet is a lot of lost coastal area. So I've always felt very skeptical that the absence of earlier archeological sites proved anything.

You're not alone.

https://en.wikipedia.org/wiki/Coastal_migration#Sea_levels

I think most informed people share that skepticism. The entirety of the human story is probably many times more interesting than we know. But it's only scientifically responsible to include the well-attested facts in basic education.

That said, I do think a permissive imagination can be key to being receptive to new facts that support surprising outcomes. The impact of speculation and philosophy on science is underrated, in my opinion.

Something just seems wrong about the timeline. Not the NA timeline, I mean the European timeline.

We have seafarers reaching Australia 40,000 years ago. I don't think it should come as a shock that seafarers reach North America 24,000 years ago. Except that maybe we should keep digging because why did it take 16,000 more years?

I think we may be labeling the Dawn of Civilization pretty badly when we have agriculture and intercontinental tribes debuting thousands or tens of thousands of years prior.

Maybe the first inland civilization, sure.

The something you're looking for may be the ice age.

Personally I wouldn't be terribly surprised to hear that humans reached Alaska either before or after the last ice age. But right in the middle? Strange timing.

I heard the story [1] that when people where able to cross the bering street due to the lower sea level, they could not proceed from Alaska due to the massive ice shield and when the shield was gone, the bering street was closed again, a mechanism described to be similar to a revolving door.

[1] Tim Flannery (2001), The Eternal Frontier: An Ecological History of North America and its Peoples

Yeah, I've read it too, but it's odd.

It's more difficult to move on ice or water than on grass. Moving on grass is convenient. But ice and water aren't impossible, we know that people reached Greenland from the northwest and stayed there, and we know that people reached Australia and even Easter Island.

Well-regarded books say strange things sometimes. Have you read Jared Diamond's Catastrophe? Its argument about why the Norwegians who moved to Greenland died presupposes that the technology that led to viking ships had nothing to do with fishing and, and states that Norwegians would rather hunger to death than eat fish.

I think you mean Collapse (https://en.wikipedia.org/wiki/Collapse:_How_Societies_Choose...)? Do you have more rebuttal to that? I'm reading it at the moment, and I'm always looking for issues with JD's usually compelling arguments.

Yes, Collapse, sorry.

No, I don't, really. Except that dried cod was a well-known foodstuff in Norway at the time, that's a recorded fact. Any argument that rests on Norwegians not eating cod is a poorly founded argument, no matter how well phrased.

(http://nrksuper.no/super/files/2013/10/t%C3%B8rrfisk2-e13823... is it. Tastes good, is light and doesn't require refrigeration. Smells though.)

Well, the seafarers reching Australia/Neuginea 40,000 years ago certainly had a much short distance to travel on the open sea. I can't find any good visualizations now but the difference between about 100 kilometers of open sea and multiple thousand is enormous. And going over the bering street wasn't that easy either like through the much harsher climate back then.

People can usually walk away faster than sea level can rise, so even if many of the piles of bones and pottery are now under water, the DNA of the inhabitants might not be. I'm hoping we'll soon be able to recover more of the early history of human migrations via DNA in living descendants.

We're apparently getting closer to being able to do an entire human gene sequencing for about $100. A $100 million project over the next generation or so could get us the complete genomes of a million people. Donated genomes could increase that number significantly. With enough data and improvements in algorithms, ever more subtle "shadows" of ancient people will emerge.

In addition, the ability to recover/reconstruct DNA from known archaeological sites will grow rapidly. The degradation of old DNA can be compensated for statistically, to some extent, by having many more samples. The number of samples will grow as the cost per sample falls, and the cost is plummeting.

In other words, we may not have to find a lot of new sites to experience a rush of new discoveries in the very near future. I'm looking forward to it.

Those people didn't die in a flood - instead, over thousands of years, they relocated their communities further inland. Unfortunately, this means that when we dig at a settlement, all we can hope to find is fairly recent artifacts. (As the old settlement is now underwater.)

Those people didn't die in a flood - instead, over thousands of years, they relocated

Yes, that's exactly what I said. They walked away from the coast as sea levels rose, taking their DNA with them.

Not just North America. The "Out of Arabia" scenario for AMH expansion from the now-underwater Levant is quite compelling and revolutionary, but obviously difficult to prove.

[1] http://dienekes.blogspot.com/2014/09/an-archaeological-scena...

[2] https://www.academia.edu/8214444/Out_of_Arabia_and_the_Middl...

Along most of the west coast of North America, the Pacific Ocean depth drops down past 400ft within a couple miles of shore. When we go scuba diving we're never far from land. So certainly some sites are now underwater, but as long as the people spent time at least a little ways inland then there should be evidence near the current coastline.

Yep. Not so much of a shelf here as a plummet. One of the things that makes Monterey Bay so interesting, for example.

which makes me realize - none of the current coral reefs existed back then, and the ones that were are no longer there (since corals need warm water near surface to thrive). and probably number of sea species that went extinct

Most ancient people were smart enough (or learned the hard way) to not build their cities on the coast. Most major coastal cities you can think of today -- New York, Singapore, Shanghai, Tokyo -- have only a couple hundred years of history as a city.

Most cities that were sizably developed in ancient times -- such as Paris, Beijing, Moscow, Rome, Kyoto, Xi'an, London -- were not built on the coast for good reasons. I suspect that the humans in North America would have also avoided living too close to the coast if they were smart.

I disagree - we may not have built large settlements by the coast but there are thousands of small towns on the coastlines of the world that were essential in the exploration of the world that drove settlement.

The location of ancient capitals probably has more to do with the importance of trade and food production than avoiding coastal storms or flooding.

Not really, as coastal city can also benefit from fishing, and certain coastal area had maritime trade back in ancient times.

But it's not sea level either, my understanding is that the reason why most ancient capitals are built inland is military.

Coastal areas are harder to defend from foreign invasions than inland areas, as there is little signal and time to mobilize troops, moreover, martial strategy privileges high ground.

Capitals were usually built around a river that connects to the sea, and where that river meets the sea, you can usually find a fortified town which had a military garrison.

My guess is that the advent of the airplane bomber has changed the considerations.

Did you mean to reply to me? I ask because your comment appears to be disagreeing with arguments that I never made.

My major point was that (1)the coast, by itself, was not a critical factor either pro or con. (2) What appears to matter when it comes to becoming a first rate city is food production and access to trade, be it by road, river, or sea--preferably, all three.

Your defense thesis doesn't make sense. If defense really mattered, cities would be built on mountain tops, but they aren't. Instead, cities grow where trade flourishes. They take their lumps, periodically, from invasion, and then rebuild and get back to business. Virtually every major city from the ancient world is still in business, even though the empire that founded it has long since been destroyed. Only when the economic basis of the city gets destroyed, does the city die. That argues for economics trumping military considerations, which, again, was my thesis.

Finally, bombers don't appear to have altered this equation one bit. To the best of my knowledge, the major cities from before WWII are still major cities today.

Yes I meant to reply to you. I think we are confounding flourishing cities and capitals. I was more talking specifically about the later. Most ancient and especially modern capitals (D.C., Canberra, Ottawa etc.) are built inland, but the land mass offer less protection than it did in ancient times, not so much because of bombers actually (land offers ground air defense), but missiles, which were rendered effective at the end of WWII (V-2). Nonetheless it is still a preferred configuration for capitals for the same factors. Coastal cities are just more vulnerable in times of war.

Moscow was founded in the ~11th century. It only became the sprawling metropolis of today because of a series of historical accidents, that had more to do with who won what war, then its superior location.

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