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.
Some 42,000 years ago, in an event known as the Laschamp Excursion, the poles did just that for around 800 years, before swapping back — but scientists were unsure exactly how or if it impacted the world.
Now, a team of researchers from Sydney’s University of New South Wales and the South Australian Museum say the flip, along with changing solar winds, could have triggered an array of dramatic climate shifts leading to environmental change and mass extinctions.
Scientists analyzed the rings found in ancient New Zealand kauri trees, some which had been preserved in sediments for more than 40,000 years, to create a timescale of how Earth’s atmosphere changed over time.
Using radiocarbon dating, the team studied cross sections of the trees — whose annual growth rings served as a natural time stamp — to track the changes in radiocarbon levels during the pole reversal.
“Using the ancient trees we could measure, and date, the spike in atmospheric radiocarbon levels caused by the collapse of Earth’s magnetic field,” Chris Turney, a professor at UNSW Science, director of the university’s Earth and Sustainability Science Research Center and co-lead author of the study, said in a statement.
The team compared their new timescale with site records from caves, ice cores and peat bogs around the world.
‘End of days’
Researchers found that the reversal led to “pronounced climate change” … Click source below to read more.
Earth’s magnetic north pole is heading for Russia and scientists are puzzled
By Ashley Strickland, CNN, December 18, 2019
Unlike its geographical poles, Earth’s magnetic poles that serve as the foundation of our navigation are actively moving.
The north magnetic pole has been slowly moving across the Canadian Arctic toward Russia since 1831, but its swift pace toward Siberia in recent years at a rate of around 34 miles per year has forced scientists to update the World Magnetic Model – used by civilian navigation systems, the North Atlantic Treaty Organization, and US and British militaries – a year ahead of schedule.
The World Magnetic Model 2020 forecasts that the pole will continue on its path to Russia, but now the speed is slowly decreasing to about 24.8 miles per year. Since its discovery in 1831, the pole has traveled 1,400 miles.
The magnetic field reverses its polarity every several hundred thousand years, where the magnetic north pole resides at the geographic South Pole. The last reversal took place 770,000 years ago.
In a new study, researchers discovered that the last field reversal took 22,000 years to complete – much longer than anticipated or expected, the researchers said.
Although some believe reversals could happen over the course of a human life, the findings don’t support that theory.
Researchers were able to study the reversal by analyzing a global survey of ocean sediments, Antarctic ice cores and lava flows.
The details within those samples revealed how Earth’s magnetic field has weakened, shifted partially, stabilized and reversed over a million years.
“Reversals are generated in the deepest parts of the Earth’s interior, but the effects manifest themselves all the way through the Earth and especially at the Earth’s surface and in the atmosphere … ” Read more.
