4 ms·

A global environmental crisis 42,000 years ago

29 points by divbzero 6y ago

aritmo 6y ago
Sadly the full text is not freely available. ScienceMag demands $15. Is Sci-Hub down? Some of the presumably mirrors redirect to ScienceMag instead.
- akeck 6y ago
  There's details here: https://newsroom.unsw.edu.au/news/science-tech/ancient-relic-points-turning-point-earths-history-42000-years-ago https://newsroom.unsw.edu.au/news/science-tech/ancient-relic...
Supersaiyan_IV 6y ago
https://phys.org/news/2021-02-ancient-relic-earth-history-years.html https://phys.org/news/2021-02-ancient-relic-earth-history-ye... "Ancient relic points to a turning point in Earth's history 42,000 years ago" Just because this article's title is less sensationalistic, doesn't make it any less interesting.
DiabloD3 6y ago
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018RG000629 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/201... Here's a good paper from 2019 that covers this in depth. "The past strength of Earth's dipole field provides a proxy for UVR flux because of its role in maintaining stratospheric ozone." [...] "The demise of Neanderthals at ~41 ka can now be closely tied to the intensity minimum associated with the Laschamp magnetic excursion, and the survival of anatomically modern humans can be attributed to differences in the aryl hydrocarbon receptor that has a key role in the evolutionary response to UVR flux."
- trhway 6y ago
  While the rest of the body can be protected with bodily hair, animal pelts, grasses, tree leaves, dirt (or something like ochre mentioned in the article), etc. the eyes is the only body part that couldn't be protected from UV back then. When compared to Cro-Magnon, Neanderthals had bigger (and most probably light colored) eyes adapted to the lower light of their more Northern areas. So quick rise in UV (especially if it was not accompanied by the similar scale rise in the total amount of visible light to trigger eyes f-stop equivalent) would have made for noticeable chronic damage to retina and other parts of the eye (googling UV eye damage brings a lot of possibilities), etc. which would be one more factor against them in competition with the Cro-Magnon whose eyes had evolved in the higher UV environment of Africa.
godmode2019 6y ago
I posted this yesterday [Ancient kauri shows magnetic pole shift 42,000 years ago]( https://www.tvnz.co.nz/one-news/new-zealand/ancient-kauri-reveal-secrets-life-earth-after-magnetic-pole-shift-42-000-years-ago https://www.tvnz.co.nz/one-news/new-zealand/ancient-kauri-re...)

29 points by divbzero 6y ago

Sadly the full text is not freely available. ScienceMag demands $15. Is Sci-Hub down? Some of the presumably mirrors redirect to ScienceMag instead.

akeck 6y ago
There's details here: https://newsroom.unsw.edu.au/news/science-tech/ancient-relic-points-turning-point-earths-history-42000-years-ago https://newsroom.unsw.edu.au/news/science-tech/ancient-relic...

Supersaiyan_IV 6y ago

https://phys.org/news/2021-02-ancient-relic-earth-history-years.html https://phys.org/news/2021-02-ancient-relic-earth-history-ye... "Ancient relic points to a turning point in Earth's history 42,000 years ago" Just because this article's title is less sensationalistic, doesn't make it any less interesting.

DiabloD3 6y ago

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018RG000629 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/201... Here's a good paper from 2019 that covers this in depth. "The past strength of Earth's dipole field provides a proxy for UVR flux because of its role in maintaining stratospheric ozone." [...] "The demise of Neanderthals at ~41 ka can now be closely tied to the intensity minimum associated with the Laschamp magnetic excursion, and the survival of anatomically modern humans can be attributed to differences in the aryl hydrocarbon receptor that has a key role in the evolutionary response to UVR flux."

trhway 6y ago
While the rest of the body can be protected with bodily hair, animal pelts, grasses, tree leaves, dirt (or something like ochre mentioned in the article), etc. the eyes is the only body part that couldn't be protected from UV back then. When compared to Cro-Magnon, Neanderthals had bigger (and most probably light colored) eyes adapted to the lower light of their more Northern areas. So quick rise in UV (especially if it was not accompanied by the similar scale rise in the total amount of visible light to trigger eyes f-stop equivalent) would have made for noticeable chronic damage to retina and other parts of the eye (googling UV eye damage brings a lot of possibilities), etc. which would be one more factor against them in competition with the Cro-Magnon whose eyes had evolved in the higher UV environment of Africa.

godmode2019 6y ago

I posted this yesterday [Ancient kauri shows magnetic pole shift 42,000 years ago]( https://www.tvnz.co.nz/one-news/new-zealand/ancient-kauri-reveal-secrets-life-earth-after-magnetic-pole-shift-42-000-years-ago https://www.tvnz.co.nz/one-news/new-zealand/ancient-kauri-re...)