The reversal of the Earth’s magnetic poles with a decline in solar activity 42,000 years ago could have generated an apocalyptic environment that could have played a role in a major event ranging from extinction megafauna in late Neanderthals, researchers say
Earth’s magnetic field acts as a protective shield against harmful cosmic radiation, but when the poles change, as has happened several times in the past, the protective shield weakens considerably and leaves the planet exposed to high energy particles
A temporary pole reversal, known as the Laschamps excursion, occurred 42,000 years ago and lasted around 1,000 years.Previous work has found little evidence that the event took place. a profound impact on the planet, perhaps because the focus had not been on the period in which the poles were actually moving, researchers say
Now scientists say the turnaround, coupled with a period of low solar activity, could have been the source of a wide range of climatic and environmental phenomena with dramatic ramifications. “It probably would have felt like the end of days Said Professor Chris Turney of the University of New South Wales and co-author of the study
The team collectively called this period the “Adams Event”, a nod to Douglas Adams, author of The Hitchhiker’s Guide to the Galaxy in which 42 was seen as the “Answer” to the ultimate question of life, the universe and everything “
In the journal Science, Turney and colleagues describe how they performed radiocarbon analyzes of ancient kauri rings preserved in the wetlands of northern New Zealand, some of which were over 42,000 years old.
This allowed them to track over time the increase in carbon-14 levels in the atmosphere produced by increasing levels of high-energy cosmic radiation reaching Earth during the Laschamps excursion. were able to date atmospheric changes in more detail than those offered by previous records, such as mineral deposits
They then examined numerous recordings and materials from around the world, including lake and ice cores, and found that a host of major environmental changes were occurring as carbon-14 levels hit. their maximum
“We are seeing this massive growth of the ice sheet over North America we see the tropical rain belts in the west pacific shifting dramatically at this point, then also the wind belts in the south ocean and a drying out in Australia, ”Turney said
The researchers also used a model to examine how the chemistry of the atmosphere might change if the Earth’s magnetic field was lost and if there was an extended period of low solar activity, which would have further reduced the protection of Earth against cosmic radiation Ice core records suggest that such declines in solar activity, known as “great solar minima”, coincided with the Laschamps excursion
Results reveal that atmospheric changes could have led to huge changes in climate, electrical storms and widespread colorful auroras
Besides the environmental changes that could accelerate the growth of ice caps and contribute to the extinction of Australian megafauna, the team suggests they could also be linked to the emergence of red ocher handprints , the suggestion being that humans may have used the pigment as a sunscreen against increased levels of ultraviolet radiation hitting Earth due to ozone depletion
They also suggest that the increase in cave use by our ancestors during this time, as well as the rise of rock art, could be due to the underground spaces providing shelter from the harsh conditions. The situation could also have stimulated competition, potentially contributing to the end of Neanderthals, Turney said.
Earth’s magnetic field has weakened by around 9% over the past 170 years, and researchers say another turnaround could be considered Such a situation could have a dramatic effect, including devastating power grids and satellite networks
Richard Horne, head of space, weather and atmosphere at the British Antarctic Survey, who was not involved in the work, said the chemical changes in the upper atmosphere predicted by the study matched to what had been measured at the Halley research station in Antarctica during strong but short-lived events during which energetic particles were emitted by the sun
But could the environmental effects have been as severe as the team predicted? “Maybe not as extreme, but it gives you pause to think,” Horne said, noting that Earth’s magnetic field was unlikely to disappear completely.
Dr Anders Svensson of the University of Copenhagen, however, said ice cores from Greenland and Antarctica show no evidence of dramatic climate change around the time of the excursion to Laschamps, but that does not exclude that it has an impact “The changes in the ozone layer and the impact of increased UV radiation on humans is not something that we can confirm or reject from carrots of ice, ”he said
Chris Stringer, who studies human origins at the Natural History Museum in London, said the work was important He said the increased use of caves as shelter was plausible, but the link with an increase in rock art was less convincing as paintings of pigs were apparently produced in Sulawesi in Indonesia long before the Laschamps excursion
“The authors also make a connection with the physical extinction of the Neanderthals around 40,000 years ago and I think this certainly could have contributed to their demise,” he said. “But they survived longer and spread more widely than Europe alone, and we have a very bad idea of when they finally disappeared in parts of Asia.”
Dr Richard Staff, a quaternary geochronology researcher at the University of Glasgow, said the study was exciting and noted that it could lead to further investigation into the environmental and evolutionary effects of other downturns more dramatic effects of the earth’s magnetic field force further in time
Earth, Earth’s magnetic field, geomagnetic inversion, swamp kauri, magnetism, Laschamp event
Ebene News – UA – End of the Neanderthals linked to the reversal of the Earth’s magnetic poles, according to a study