About 42 years ago, the Earth experienced a change of magnetic poles, which coincided with serious climatic changes and mass extinctions, according to the International Research Group.
According to the press service of St. Petersburg State University, Yevgeny Rozanov, head of the SPbSU mega-grant and an expert in the field of solar-terrestrial effects, worked on the research as part of a group led by scientists from the University of New South Wales and the South Australian Museum. The results of the research are published in the journal Science.
Scientists call the climatic changes that occurred 42 years ago the Adams event, and the last change in the magnetic poles that occurred in the middle of the Ice Age — about 000 to 41 years ago — was called the Lachamp event.
Until recently, not only the exact date of the pole shift, but also how this change affected the climate and life on Earth remained a mystery to scientists.
To learn more about this chapter in the history of the planet, climatologists were helped by the New Zealand kaura tree, the trunk of which was discovered about two years ago in Northland, the northernmost region of New Zealand, in sediments older than 40 thousand years.
"Thanks to radiocarbon dating, researchers were able to track changes in the amount of radiocarbon precisely at the time of the shift of the magnetic poles, which, together with data on the age of trees around the world, made it possible to build a climate model of that time and restore the chain of ecological events," the message says.
Scientists managed to find out that that period was associated with electrical storms and frequent aurora borealis. Due to the migration of the poles, the Earth's magnetic field during the Adams event decreased to 0-6% of its current strength, which significantly weakened the Earth's protection against cosmic radiation. In addition, at that time the Sun experienced several large solar minima, which made the protective "screen" even thinner. As a result, as the researchers noted, the ionized air practically "fried" the ozone layer and started a wave of climate change on the entire planet.
The authors of the paper assume that the extinction of the megafauna on the mainland of Australia and Tasmania 42 thousand years ago was connected with the Adams event.
"The article suggests that it influenced the extinction of the Neanderthals and the wide spread of rock painting in that period. Perhaps, scientists note, new environmental conditions forced ancient people to seek refuge precisely in caves. There, the first drawings were preserved, and on open surfaces they were destroyed, creating the impression that rock painting suddenly appeared 42 years ago," says the press release.
The authors of the scientific article are concerned that today the North Magnetic Pole is also shifting, and the magnetic field is gradually weakening, which may indicate a repeat of the past scenario.
Moreover, due to the fact that the Earth's atmosphere is filled with carbon like never before, the consequences of such an event can be colossal: from the destruction of electrical and satellite networks to an unprecedented acceleration of climate change on the planet.
