A new international study suggests that a reversal of the magnetic field – combined with changing solar winds – contributed to an environmental crisis and mass extinctions 42,000 years ago. It happened around the time of the demise of the Neanderthals, an extinct human species that once roamed what is now Europe, these scientists said, and it would have come with electrical storms, widespread auroras and an influx of cosmic rays. One of the researchers in the video above commented:
… it would have been incredibly scary.
The authors of the study described this catastrophic period Adams Transitional Geomagnetic Event, or Adams event, a reference to a trope created by Douglas Adams, author of the science fiction comedy series The Hitchhiker’s Guide to the Galaxy. Adams famously wrote that 42 was the answer to:
… Life, the universe and everything.
The University of New South Wales (UNSW) Sydney and the South Australian Museum jointly led the study, which was published in the peer-reviewed journal on February 19, 2021 ScienceAs UNSW’s Chris Turney – a co-author of the study – explained in a statement:
Earth’s magnetic field dropped to just 0 to 6% strength during the Adams event. We essentially had no magnetic field at all. Our cosmic ray shield was completely gone.
Since the magnetic reversal of 42,000 years ago helped trigger Earth extinctions, these scientists said, the sky would be illuminated by widespread auroras. These scientists suggest the reversal could help explain evolutionary mysteries, such as the extinction of Neanderthals. Image via Unsplash / UNSW.
The results were impressive. Solar flares and galactic cosmic rays shattered particles in the Earth’s atmosphere, ionized the air and zapped out the ozone layer. Our ancestors would have seen shocking light shows in the sky both during the day and at night. Normally confined to the polar regions, Aurorae is said to have spread all over the world. The ionized air would have been an excellent conductor for electrical storms, increasing their frequency.
The overhead turbulence – and the loss of UV protection from the ozone layer – could explain the sudden rise of cave art as early humans retreated to caves for protection.
Like Science magazine reported on Feb. 18:
… The world was turned upside down – at least magnetically.
The oldest cave art known in Europe, about 42,000 years old, is located in the El Castillo cave in Spain. These red handprints could be related to an ancient form of sunscreen. Image via Paul Pettitt / Gobierno de Cantabria / UNSW.
Trees were the key to the mystery
The kauri tree, the largest tree species in New Zealand, was key to understanding this ancient environmental crisis. Kauri trees, also called the God of the Forest, are some of the oldest forests in the world. A 60-ton trunk of a kauri tree was found several years ago by workers breaking the ground for a power plant in New Zealand. The tree, which was preserved in a swamp, turned out to be 42,000 years old and a valuable time capsule for scientists. Its rings spanned some 1,700 years and recorded the magnetic reversal.
This brief magnetic reversal was known before, but the terrestrial effects were previously believed to be mild. The event was discovered in the 1960s in the lava flows of Laschamps in Clermont-Ferrand, France, and is attested by magnetic studies of the ancient lava. This magnetic reversal was short lived; it was what scientists called an excursion: not a permanent change in the Earth’s magnetic field, but only a temporary change. As you may know, the Earth’s north and south magnetic poles are not fixed or connected to the Earth’s rotational axes. The magnetic poles wander and wobble and switch completely from time to time, as appears to have happened temporarily 41,000 to 42,000 years ago. This particular temporary switch took about 800 years before being rolled back. It is now called the Laschamps Event, or the Laschamp excursion.
This old cowrie block was alive during the Adams event. Image via Nelson Parker.
As Turney explained:
For the very first time, we have been able to accurately date the timing and environmental impact of the last magnetic pole switch. The findings were made possible with ancient New Zealand kauri trees, which have been preserved in sediments for over 40,000 years. Using the ancient trees, we were able to measure and date the peak in atmospheric carbon levels caused by the collapse of the Earth’s magnetic field.
The Laschamp Event thus refers to the magnetic pole reversal itself. The new term used by scientists in 2021 – the Adams event – more broadly refers to effects on Earth during that time. Earth appears to have seen an increase in aurorae, electrical storms and cosmic rays, increasing the atmospheric level of radiocarbon. The researchers have linked these events to the extinction of megafauna in mainland Australia and Tasmania 42,000 years ago.
Scientists have conducted many investigations into the malfunction during the Laschamp Event. The new study focused on the period leading up to the Laschamp event, when Earth’s magnetic fields migrated to their opposite positions. The scientists discovered that during this period the earthly unrest was greatest.
By studying the kauri tree, researchers were able to create a more detailed timeline of the Laschamp event. As Alan Cooper of the South Australian Museum further explained:
The kauri trees are like the Rosetta stone and help us link together data about environmental changes in caves, ice cores and peatlands around the world.
Could it happen today?
There is some evidence that a change in the orientation of the Earth’s magnetic field is already underway. Scientists have been tracking the magnetic North Pole faster in recent years than in the past. And in the past 170 years, the Earth’s magnetic field has weakened by about 9%.
Modern society’s reliance on the power grid and satellites has what it takes to bring a dystopian novel to life, as incoming radiation destroys our sources of power and communication. The issue of climate change adds an additional disaster, according to Turney:
Our atmosphere is already filled with carbon at levels that humanity has never seen before. A magnetic polar reversal or extreme change in the activity of the sun would be unprecedented accelerators of climate change. We urgently need to cut CO2 emissions before such a random event occurs again.
Bottom Line: Radiocarbon dating in kauri trees helped researchers link the reversal of the magnetic field 42,000 years ago to environmental disasters and extinction events.
Source: a global environmental crisis 42,000 years ago
Via UNSW Sydney
