Reversal of Earth's magnetic poles may have triggered Neanderthal extinction – and it could happen again
(CNN)The reversal of Earth's magnetic poles, along with a temporary breakdown of the world's magnetic field about 42,000 years ago, could have triggered a raft of environmental changes, solar storms and the extinction of the Neanderthals, according to a new study.
The Earth's magnetic field protects us, acting as a shield against the solar wind (a stream of charged particles and radiation) that flows out from the sun. But the geomagnetic field is not stable in strength and direction, and it has the ability to flip or reverse itself.
'End of days'
Researchers found that the reversal led to "pronounced climate change." Their modeling showed that ice sheet and glacier growth in North America and shifts in major wind belts and tropical storm systems could be traced back to the period of the magnetic pole switch, which scientists named the "Adams Event."
"Effectively, the Earth's magnetic field almost disappeared, and it opened the planet up to all these high energy particles from outer space. It would've been an incredibly scary time, almost like the end of days," Turney said.
Researchers say the Adams Event could explain many of Earth's evolutionary mysteries, including the extinction of Neanderthals and the sudden widespread appearance of figurative art in caves worldwide.
The phenomenon would have led to some dramatic and dazzling events. In the lead-up to the Adams Event, the Earth's magnetic field dropped to only 0% to 6% of its strength, while the Sun experienced several long lasting periods of quiet solar activity.
"We essentially had no magnetic field at all – our cosmic radiation shield was totally gone," Turney said.
The weakening of the magnetic field meant that more space weather, such as solar flares and galactic cosmic rays, could head to Earth.
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"Unfiltered radiation from space ripped apart air particles in Earth's atmosphere, separating electrons and emitting light – a process called ionisation," said Turney in a statement. "The ionised air 'fried' the Ozone layer, triggering a ripple of climate change across the globe."
During this time, Earth's inhabitants would have been subjected to some dazzling displays northern and southern lights, caused by solar winds hitting the Earth's atmosphere, would have been frequent. Meanwhile, the ionized air would've increased the frequency of electrical storms something that scientists think caused humans to seek shelter in caves.
An upcoming reversal
In the paper, published in the journal Science, experts say there is currently rapid movement of the north magnetic pole across the Northern Hemisphere – which could signal another reversal is on the cards.
"This speed alongside the weakening of Earth's magnetic field by around nine per cent in the past 170 years could indicate an upcoming reversal," said Cooper.
"If a similar event happened today, the consequences would be huge for modern society. Incoming cosmic radiation would destroy our electric power grids and satellite networks," he said.
Human activity has already pushed carbon in the atmosphere to levels "never seen by humanity before," Cooper said.
"A magnetic pole reversal or extreme change in Sun activity would be unprecedented climate change accelerants. We urgently need to get carbon emissions down before such a random event happens again," he added.
https://www.cnn.com/2021/02/19/world/magnetic-fields-earth-intl-scli-scn/index.html?