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A new international study suggests that a reversal of the magnetic field – combined with shifting solar winds – contributed to an environmental crisis and mass extinctions 42,000 years ago. This 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 radiation. One of the researchers in the video above commented:
… It would have been incredibly scary.
The authors of the study named this catastrophic period Adams transitional geomagnetic event, or Adams event, a reference to a trope created by Douglas Adams, author of the sci-fi comedy series The Hitchhiker’s Guide to the Galaxy. Adams wrote that 42 was the answer to:
… Life, the universe and everything.
The University of New South Wales (UNSW) in Sydney and the South Australian Museum co-led the study, which was published on February 19, 2021 in the peer-reviewed journal Science. As Chris Turney of UNSW – a co-author of the study – explained in a statement:
The Earth’s magnetic field dropped to only 0-6% strength during the Adams event. We had virtually no magnetic field. Our shield of cosmic radiation was totally gone.
As the magnetic reversal of 42,000 years ago helped cause earthly extinctions, the scientists said, the sky would have been lit by diffuse auroras. These scientists suggest that the reversal could help explain mysteries of evolution, such as the extinction of the Neanderthals. Image via Unsplash / UNSW.
The results have been spectacular. Solar flares and galactic cosmic rays tore particles from Earth’s atmosphere, ionizing the air and zapping the ozone layer. Our ancestors would have witnessed shocking light shows in the sky day and night. The auroras, normally confined to the polar regions, would have spread across the globe. Ionized air would have been an excellent conductor for electrical storms, increasing their frequency.
The turbulence occurring above the head – and the loss of UV protection from the ozone layer – could explain the sudden emergence of rock art as early humans retreated into caves for protection.
As Science the magazine reported on February 18:
… The world has been turned upside down – at least magnetically speaking.
The oldest known rock art in Europe, some 42,000 years old, is found in the El Castillo cave in Spain. These red handprints may 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, New Zealand’s largest tree species, has been key to understanding this ancient environmental crisis. Sometimes referred to as the god of the forest, kauri trees make up some of the oldest forests in the world. A 60-ton trunk of a kauri tree was discovered several years ago by workers preparing the ground for a power plant in New Zealand. The tree, which had been preserved in a bog, turned out to be 42,000 years old and a valuable time capsule for scientists. Its rings lasted about 1,700 years and captured the magnetic reversal.
This brief magnetic reversal was known before, but previously its earthly effects were considered mild. The event was discovered in the 1960s in the Laschamps lava flows in Clermont-Ferrand, France, highlighted in magnetic studies of ancient lava. This magnetic reversal was brief; it was what scientists called an excursion: not a lasting change in Earth’s magnetic field, but just a temporary change. As you may know, the magnetic north and south poles of the Earth are not fixed or related to the axes of rotation of the Earth. The magnetic poles wander and wobble and, at times, shift places entirely, as seems to have happened temporarily 41,000 to 42,000 years ago. This particular temporary change lasted for about 800 years before returning. It is now called the Laschamps event, or the Laschamp excursion.
This ancient kauri diary lived during the Adams event. Image via Nelson Parker.
As Turney explained:
For the first time, we were able to accurately date the timing and environmental impacts of the last magnetic pole switch. The finds were made possible with ancient New Zealand kauris, which have been preserved in sediments for more than 40,000 years. Using the ancient trees, we were able to measure and date the peak in atmospheric radiocarbon levels caused by the collapse of the Earth’s magnetic field.
Thus, the Laschamp event refers to the reversal of the magnetic pole itself. The new term used by scientists in 2021 – the Adams event – refers more broadly to the effects on Earth during this period. Earth appears to have experienced an increase in auroras, electrical storms, and cosmic radiation, causing atmospheric radiocarbon levels to rise. Researchers have linked these events to the 42,000-year-old megafauna extinction on mainland Australia and Tasmania.
Scientists have done numerous studies on the blackout during the Laschamp event. The new study focused on the period leading up to the Laschamp event, as magnetic fields migrated through the Earth to their opposite positions. Scientists have discovered that this period is when earthly troubles were at their peak.
By studying the kauri tree, the researchers were able to create a more detailed timeline of the Laschamp event. As Alan Cooper of the South Australian Museum explained:
Kauri trees are like the Rosetta Stone, which helps us link records of environmental changes in caves, ice cores, and bogs around the world.
Could this happen today?
Some evidence suggests that a shift in the orientation of the Earth’s magnetic field is already underway. Scientists have been tracking the wandering of the North Magnetic Pole faster in recent years than in the past. And over the past 170 years, the Earth’s magnetic field has weakened by about 9%.
Modern society’s dependence on the electricity grid and satellites has all the makings for a dystopian novel to come to life, if the incoming radiation destroys our sources of energy and communication. The issue of climate change adds an additional element of disaster, according to Turney:
Our atmosphere is already filled with carbon to levels never seen by mankind before. A reversal of the magnetic poles or an extreme change in solar activity would be accelerators of unprecedented climate change. We urgently need to reduce carbon emissions before such a random event happens again.
Conclusion: Radiocarbon dating in kauri trees has helped researchers link the reversal of the magnetic field 42,000 years ago to environmental calamities and extinction events.
Source: A global environmental crisis 42,000 years ago
Via UNSW Sydney
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