Summary
February 20, 2021: A newly released scientific paper makes the deduction that the magnetic pole shift that happened 42,000 years ago (roughly the 40th Century BC) caused the extinction of neanderthals and most species of megafauna. The polar shift disrupted the Earth's magnetic field, allowing more cosmic ray radiation to reach the earth. These cosmic rays broke down ozone, which in turn let more ultraviolet light into the Earth's atmosphere. Skin cancer and mutation rates went up as diurnal animals world wide got bad sunburn. This also lead to climate change and disruption of weather patterns, so basically one disaster after another. It would be extra bad if this magnetic flip on earth coincided with a time of bad solar flare activity.
Primitive man may have survived by seeking shelter in caves (see caveman), and the article proposes that the increased frequency of cave painting at this time is evidence of that. It even suggests all those hand images in caves may have been some sort of record of people using ochre-colored "sunscreen".
Towards the end of the article it discusses recent variations in the earth's magnetic field and poles, just to make you worry that it might happen again. Apparently the magnetic flip-flop happens 4 or 5 times every million years, and has the potential to cause massive upheavals and extinctions whenever it does.
Source
Game and Story Use
- Could be used in an after the end scenario, where your fictional civilization is blotted out of existence by some terrible ecological collapse and disaster plotline. Climate change and death rays from the sky! Combine it with sunspot shenanigans for extra craziness. Compasses stop working, the sky becomes toxic, and people abandon their homes to live in caves or subway tunnels. Steal your favorite bits from the September 1859 Geomagnetic Storm or Venus Was Potentially Habitable pages to add to the timeline of Post-Apocalyptic Decay.
- For a recent alternate history scenario, you could say this sort of thing happened at Y2K or in the change of the Mesoamerican long-count calendar in 2012.
- If you've got a monster or cryptid that could easily run out of control and wipe out humanity (like in "the Thing"), you could give it the classic weakness of being succeptible to sunlight or radiation. Maybe man's greatest predator was a species of vampire (or whatever else floats your boat) that was mostly eradicated in 40,000 BC, allowing us to flourish and build cities when it was gone. A few survived deep within the earth, and pop up from time to time on the surface, but can't deal with our levels of background radiation.
- If mankind invents a shield to protect us from EMP and solar flares, it might mean these creatures are able to re-emerge and conquer the earth!
- In the Continuum RPG, there's a fun nugget of canonical setting subversion hidden in one of these times of magnetic flip-flop. An early civilization developed anachronistic technology and caused a collapse of causality scenario that shifted the earth on its axis, changed magnetic north, wiped out their civilization, and created a barrier that is impenetrable by time travel tech. You have to get really high-"level" characters before you've got the ability to go back far enough and interact with any of this stuff, but it's pretty great if and when you do, as it basically marks the point where the game gets super-epic and goes from a game about the minutia and society of being a time-traveler into basically cthulhu vs the greys.