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 at the time of the disappearance of the Neanderthals, an extinct human species that once roamed what is now Europe, these scientists said, and would have come with electrical storms, widespread auroras and an influx of cosmic radiation. One of the researchers in the video above commented:
… would have been incredibly scary.
The study’s authors called this period of time catastrophic. Adams transition geomagnetic event, or The 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 wrote this 42 was the answer to:
… life, the universe and everything.
The University of New South Wales (UNSW) Sydney and the South Australian Museum co-led the study, which was published on 19 February 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 just 0 to 6% during the Adams event. In essence, I had no magnetic field at all. Our cosmic radiation shield was completely gone.
Because the magnetic reversal of 42,000 years ago contributed to the disappearance of Earth’s disappearances, these scientists said, the sky would have been lit by widespread auroras. These scientists suggest that the reversal could help explain evolutionary mysteries, such as the disappearance of Neanderthals. Image via Unsplash / UNSW.
The results were dramatic. Solar flames and galactic cosmic rays shattered particles in the Earth’s atmosphere, ionizing the air and blowing the ozone layer. Our ancestors would have witnessed shocking light shows in the sky both day and night. Auroras, normally limited to the polar regions, would have spread around the globe. Ionized air would have been an excellent conductor for electrical storms, increasing their frequency.
The turbulence that occurs above the head – and the loss of UV protection from the ozone layer – could explain the sudden emergence of rock art as the first humans retreated to 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, about 42,000 years old, is in the El Castillo Cave in Spain. These red prints can be linked to an ancient form of sunscreen. Image by Paul Pettitt / Gobierno de Cantabria / UNSW.
Trees were the key to the mystery
The kauri tree, the largest tree species in New Zealand, was the key to understanding this ancient environmental crisis. Sometimes called 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 found a few years ago by workers who started the ground for a New Zealand power plant. The tree, which had been kept in a swamp, turned out to be 42,000 years old and a valuable time capsule for scientists. Its rings spanned about 1,700 years and captured magnetic reversal.
This brief magnetic reversal had been known before, but previously its earthly effects were thought to be 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 short; it was what scientists called a trip: not a lasting change in the Earth’s magnetic field, but only a temporary change. As you probably know, the Earth’s northern and southern poles are not fixed or connected to the Earth’s axes of rotation. The magnetic poles wander and sway and occasionally completely change places, as seems to have happened temporarily 41,000 to 42,000 years ago. This temporary switch lasted about 800 years before returning. Now it’s called the Laschamps Event or the Laschamp Trip.
This old kauri diary lived during the Adams event. Image by Nelson Parker.
As Turney explained:
For the first time, we were able to accurately date the time and environmental impact of the latest magnetic pole switch. The discoveries were made possible by kauri trees in New Zealand, which have been preserved in sediments for over 40,000 years. Using ancient trees we could measure and date the increase in atmospheric radiocarbon levels caused by the collapse of the Earth’s magnetic field.
So 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 the Earth during that time. The Earth appears to have experienced an increase in auroras, electrical storms and cosmic radiation, causing an increase in atmospheric radiocarbon levels. Researchers have linked these events to the disappearance of megafauna 42,000 years ago in mainland Australia and Tasmania.
Scientists have done many studies on the breakdown during the Laschamp event. The new study focused on the time leading up to the Laschamp Event, as magnetic fields migrated to Earth in their opposite positions. Scientists have discovered that this period is the time when the earth’s turmoil was at its peak.
By studying the kauri tree, the researchers were able to create a more detailed chronology of the Laschamp event. As Alan Cooper of the South Australia Museum further explained:
Kauri trees are like Rosetta stone, helping us to tie together records of environmental changes in caves, ice cores and peatlands around the world.
Could it happen today?
Some evidence suggests that a change in the orientation of the Earth’s magnetic field is already underway. Scientists have been tracking the North Magnetic Pole wandering faster in recent years than in the past. And in the last 170 years, the Earth’s magnetic field has weakened by about 9%.
The dependence of modern society on the electricity network and satellites has all the means for a dystopian novel to come to life, if incoming radiation destroys our energy and communication sources. The issue of climate change adds an additional element of disaster, according to Turney:
Our atmosphere is already full of carbon at levels never seen before by humanity. A reversal of the magnetic pole or an extreme change in solar activity would be unprecedented accelerators of climate change. We urgently need to reduce carbon emissions before such a random event happens again.
Bottom line: Radiocarbon dating in kauri trees has 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
