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Comment by arjunchint | Hacker News Reader

there are no guarantees in life, can look up any random day and see a meteor streaking across the sky and realize that this is the end regardless of "sociopolitical structures".

All that matters is sociotechnological progress to be able to progress further enough to overcome these tests of existence.

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> look up any random day and see a meteor streaking across the sky

That's happened rather more times in Earth's history than most folks are comfortable admitting. Tunguska would have leveled any major metropolitan city on the planet. I still think an impact is one of the more likely initiators of the Younger Dryas abrupt cooling and worldwide ~100M sealevel rise ~12,000 years ago. Conspicuously aligned with the oldest surviving traces of city living, agriculture, etc. It's increasingly accepted that a large portion of human history is 100M underwater on the continental shelves, estuaries, and other coastal areas where humans would have liked to live.

Sea level rise was much faster before the cooling of the Younger Dryas.

You're right, and here's a graph: https://en.wikipedia.org/wiki/Past_sea_level#/media/File:Pos...

It's possible the sea level rise could have initiated the cooling. But there is much disagreement as to what exactly initiated the de-glaciation which caused the sealevel rise.

The impact hypothesis for Younger Dryas isn’t really tenable. Among other things, the climate effects of a large bolide impact would be global, whereas Antarctica actually warmed during YD. This “Polar See-saw” pattern is easily explained by a northerly meltwater pulse hypothesis, but not a bolide.

It's increasingly accepted that a large portion of human history is 100M underwater on the continental shelves, estuaries, and other coastal areas where humans would have liked to live.

Any references for that? Genuine question.

Here's a review: https://www.sciencedirect.com/science/article/abs/pii/S02773...

https://www.pnas.org/doi/10.1073/pnas.1411762111

https://www.nature.com/articles/s41586-025-08769-7

https://www.academia.edu/9737879/Land_Beneath_the_Waves_Subm...

https://pure.york.ac.uk/portal/en/publications/under-the-sea...

Much appreciated - living in the UK, I have heard of Doggerland and should have expected there would be plenty of similar areas worldwide - this is interesting stuff.

It's really amazing how much more connected the world was not very long ago. Take a look at 24k years ago here: https://sea-level.vercel.app/ Nearly every continent is one connected landmass. And all the most prime real estate is now under water.

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