A new study is shedding light on how and why Neanderthals died out.
The predecessor to humans today, Homo sapiens, vanished about 42,000 years ago. Prevailing theories posited that Neanderthals gradually vanished after breeding out or were outsmarted by Homo sapiens for resources. Some scientists believe that they just died out organically, while others think the population shrunk too much to hunt and mate.
But one research team believes that the flipping of Earth’s magnetic poles around 40,000 B.C. is a likely reason the Neanderthals disappeared.
An article published Friday in the journal Science states that as Earth’s magnetic field weakened, it allowed an influx of cosmic rays to devastate animal and plant life.
The poles are generated by electric currents within the planet’s iron core, which essentially forms one large magnet. Presently, the North pole has drifted toward northern Russia.
With more cosmic radiation heating Earth, ozone concentrations lessened which allowed more ultraviolet rays into the atmosphere.
We find that geomagnetic field minima ~42 ka, in combination with Grand Solar Minima, caused substantial changes in atmospheric ozone concentration and circulation, driving synchronous global climate shifts that caused major environmental changes, extinction events, and transformations in the archaeological record.
Earth saw a lot of commotion when its magnetic poles flipped 42,000 years ago.
Scientists have known about the flip since the late 1960s. Earth’s magnetic poles aren’t static – they’re generated by electric currents from the planet’s liquid outer core, which is constantly in motion. As of late, Earth’s magnetic North pole has wandered considerably on a path toward northern Russia.
But for the most part, scientists didn’t think the last pole flip had a major environmental impact. Sure, the planet’s magnetic field got weaker, allowing more cosmic rays to penetrate the atmosphere, but plant and animal life wasn’t known to have been greatly affected.
A new study now suggests a more dramatic phenomenon occurred: The additional cosmic rays may have depleted ozone concentrations, opening the floodgates for more ultraviolet radiation in the atmosphere. Shifting weather patterns may have expanded the ice sheet over North America and dried out Australia, prompting the extinction of many large mammal species. A solar storm, meanwhile, might have driven ancient humans to seek shelter in caves.
As competition for resources grew, our closest extinct human relative, Neanderthals, may have died out.
“It would have been an incredibly scary time, almost like the end of days,” Chris Turney, an Earth scientist at the University of New South Wales, said in a video describing the new research.
h/t Digital mix guy