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A giant Kauri tree growing in Waipoua Forest, Northland, New Zealand. Researchers have studied rings in these very old trees to discern fluctuations in the Earth s magnetic poles.
An ancient, well-preserved tree that was alive the last time the Earth s magnetic poles flipped has helped scientists pin down more precise timing of that event, which occurred about 42,000 years ago.
This new information has led them to link the flipping of the poles to key moments in the prehistoric record, like the sudden appearance of cave art and the mysterious extinction of large mammals and the Neanderthals. They argue that the weakening of the Earth s magnetic field would have briefly transformed the world by altering its climate and allowing far more ultraviolet light to pour in.
February 18, 2021 at 3:02 pm
A flip-flop of Earth’s magnetic poles between 42,000 and 41,000 years ago briefly but dramatically shrank the magnetic field’s strength and may have triggered a cascade of environmental crises on Earth, a new study suggests.
With the help of new, precise carbon dating obtained from ancient tree fossils, the researchers correlated shifts in climate patterns, large mammal extinctions and even changes in human behavior just before and during the Laschamps excursion, a brief reversal of the magnetic poles that lasted less than a thousand years. It’s the first study to directly link a magnetic pole reversal to large-scale environmental changes, the team reports in the Feb. 19
Researchers say a crisis ensued the last time Earth s magnetic poles flipped : NPR npr.org - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from npr.org Daily Mail and Mail on Sunday newspapers.
End of Neanderthals linked to flip of Earth s magnetic poles, study suggests Nicola Davis Science correspondent
The flipping of the Earth’s magnetic poles together with a drop in solar activity 42,000 years ago could have generated an apocalyptic environment that may have played a role in a major events ranging from the extinction of megafauna to the end of the Neanderthals, researchers say.
The Earth’s magnetic field acts as a protective shield against damaging cosmic radiation, but when the poles switch, as has occurred many times in the past, the protective shield weakens dramatically and leaves the planet exposed to high energy particles.