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The ancient land was a much more hostile place than it is today. About 42,000 years ago, the Earth saw its magnetic poles switch. Scientists have known that the Earth’s magnetic poles have been turning since the late 1960s. Magnetic poles are not static. The poles are generated by electric currents from the liquid outer core of the planet which is constantly in motion.
We didn’t think the last pole jump had a major environmental impact. The magnetic field weakened and allowed more cosmic rays to reach the surface of the planet. Although bathed more in cosmic rays, plant and animal life does not appear to have been significantly affected. However, a new study has found that the further cosmic rise may have depleted ozone concentrations and allowed more ultraviolet radiation through the atmosphere.
Researchers believe this helped change the weather patterns that may have widened the ice sheet in North America while drying Australia out. This could have caused the extinction of many large species on the planet. The study’s authors also believe a solar storm could have pushed ancient humans into caves for shelter. According to the study, competition for resources among the remaining species could be the reason why Neanderthals became extinct.
So far, scientists have not been able to reach a consensus on what led to the extinction of Neanderthals. Some previous research has suggested that extinction occurred naturally due to inbreeding with modern humans. Others believe the Neanderthals could have been outmatched for resources as modern humans began to increase in numbers. Researchers in the new study believe it’s no coincidence that Neanderthals went extinct directly after a major shift in the planet’s magnetic poles.
Researchers looked to the ancient kauri tree that was alive in Neanderthal times for its rings to record radiocarbon levels. The rings showed signs of radiocarbon surge as the magnetic fields shifted, which is known as the Laschamps excursion. The team believe this event could have contributed to the downfall of the Neanderthals, but they admit it’s difficult to know exactly when they died.
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