The earth’s magnetic field protects us, and acts as a shield against the solar wind (a stream of charged particles and radiation) flowing from the sun. But the geomagnetic field is not stable in strength and direction, and it has the ability to turn or turn itself.
About 42,000 years ago, in an event known as the Laschamp Excursion, the Poles did so for about 800 years, before exchanging back – but scientists were not sure exactly how this would affect the world.
A team of researchers from the University of New South Wales in Sydney and the South Australian Museum say the flip along with changing solar winds could have caused a variety of dramatic climate changes that led to environmental change and mass extinctions.
Scientists have analyzed the rings in ancient New Zealand kauri trees, some of which have been preserved in sediments for more than 40,000 years, to create a time scale of how the earth’s atmosphere has changed over time.
Using radiocarbon dating, the team studied the diameter of the trees – the annual growth of which was a natural time stamp – to detect the changes in radiocarbon levels during the reversal of the pole.
“Using the ancient trees, we were able to measure and date the increase in atmospheric radiocarbon levels caused by the collapse of the Earth’s magnetic field,” said Chris Turney, a professor at UNSW Science, director of the University’s Earth. and Sustainability Research Center. and co-lead author of the study, said in a statement.
The team compared their new time scale to records of caves, ice cores and peat bogs around the world.
‘End of days’
Researchers have found that the reversal has led to “pronounced climate change”. Their modeling showed that ice plate and glacier growth in North America and shifts in large wind belts and tropical storm systems can be traced back to the period of the magnetic pole switch, which scientists called the “Adams Event”.
“Effectively, the Earth’s magnetic field almost disappeared and it opened up the planet to all these high-energy particles from outer space. It would have been an incredibly narrow time, almost like at the end of the days,” said Turney.
According to researchers, the Adams event could explain many of the Earth’s evolutionary mysteries, including the extinction of Neanderthals and the sudden widespread occurrence of figurative art in caves worldwide.
The phenomenon would have led to dramatic and dazzling events. In the run-up to the Adams event, the Earth’s magnetic field dropped to only 0% to 6% of it. power, while the sun experienced several long periods of silent solar activity.
“We actually had no magnetic field – our cosmic radiation shield was completely gone,” Turney said.
The weakening of the magnetic field meant that more space weather, such as solar flares and galactic cosmic rays, could go to Earth.
“Unfiltered radiation from space has torn apart air particles in the Earth’s atmosphere, separated electrons and emitted light – a process called ionization,” Turney said in a statement. “The ionized air ‘fried’ the ozone layer, which caused a ripple of climate change around the world.”
During this time, the inhabitants of the earth would have had some dazzling exhibits – northern and southern lights, caused by solar winds hitting the earth’s atmosphere, would have been frequent. Meanwhile, the ionized air would have increased the frequency of electrical storms – something that scientists say has led people to seek refuge in caves.
“The common cave art motif of red ocher handprints may indicate that it is used as a sunscreen, a technique still used by some groups today,” said Alan Cooper, honorary researcher at the South Australian Museum, in a statement.
“The amazing images created in the caves during this time have been preserved, while other art in open areas has since eroded, and it appears that art suddenly began 42,000 years ago,” added Cooper, co-lead author .
An upcoming turnaround
“This velocity – along with the weakening of the Earth’s magnetic field by about nine percent in the last 170 years – could signal an impending reversal,” Cooper said.
“If a similar event were to take place today, the consequences would be great for modern society. Incoming cosmic radiation would destroy our electric power networks and satellite networks,” he said.
“Human activity has already pushed the carbon into the atmosphere to a level ‘that humanity has never seen before,’ Cooper said.
“A magnetic pole reversal or extreme change in solar activity would be an unprecedented climate change accelerator. We urgently need to reduce carbon emissions before such a random event happens again,” he added.