A new international study suggests that a reversal of magnetic field – combined with changing solar winds – contributed to an environmental crisis and mass extinction 42,000 years ago. These scientists happened around the time of the downfall of the Neanderthals, an extinct human species that once wandered into what is now Europe. One of the researchers in the video above commented:
… it would have been incredibly narrow.
The authors of the study called this catastrophic period the name Adams Transitional Geomagnetic Event, of Adams Event, a reference to a trope created by Douglas Adams, author of the comedy-science fiction series The Hitchhiker’s Guide to the Galaxy. Adams wrote it famously 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 in the peer-reviewed journal on 19 February 2021. Science. As Chris Turney of UNSW – 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 actually had no magnetic field. Our cosmic radiation shield was completely gone.
Since the magnetic reversal of 42,000 years ago helped to bring about terrestrial extinctions, these scientists said that the sky would be illuminated by widespread auroras. These scientists suggest that the reversal could help explain evolutionary mysteries, such as the extinction of Neanderthals. Image via Unsplash / UNSW.
The results were dramatic. Solar flares and galactic cosmic rays tore particles into the Earth’s atmosphere, ionizing the sky and cutting off the ozone layer. Our ancestors would have seen day and night shocking flashes of light across the sky. Aurorae, usually confined to the polar regions, would have spread all over the world. The ionized air would have been an excellent conductor for electrical storms, which increased its frequency.
The overall turbulence – and the loss of UV protection from the ozone layer – may explain the sudden rise of cave art when early humans retreated to caves for protection.
As Science reported on February 18:
… the world is upside down – at least magnetically speaking.
The oldest cave art in Europe, about 42,000 years old, is in the El Castillo cave in Spain. These red handprints may be related to an ancient form of sunscreen. Image via Paul Pettitt / Governor of 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 old environmental crisis. Sometimes called the God of the forest, and kauri trees form some of the oldest forests in the world. A 60-tonne trunk from a kauri tree was found several years ago by workers breaking ground for a power station in New Zealand. The tree, preserved in a swamp, appears to be 42,000 years old and a valuable time capsule for scientists. The rings stretched for about 1700 years and captured the magnetic reversal.
This short magnetic reversal has been known before, but previously its terrestrial effects were considered mild. The event was discovered in the 1960s in the Laschamps lava flows in Clermont-Ferrand, France, as evidenced by magnetic studies of the ancient lava. This magnetic reversal was short; this was what scientists called an excursion: not a lasting change in the earth’s magnetic field, but only a temporary change. As you may know, the magnetic north and south poles of the earth are not attached or attached to the axis of rotation. The magnetic poles wander and wobble and sometimes change completely from time to time, as apparently happened 41,000 to 42,000 years ago. This particular temporary transition took about 800 years before it declined. This is now called the Laschamps event, or the Laschamp outing.
This old kauri stump lived on during the Adams event. Image via Nelson Parker.
As Turney explained:
For the first time, we were able to accurately update the timing and environmental impact of the latest magnetic pole switch. The findings were made possible by ancient New Zealand kauri trees, which have been preserved in sediments for more than 40,000 years. 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.
The Laschamp event thus refers to the reversal of the magnetic pole. The new term that scientists used in 2021 – the Adams Event – refers more widely to effects on the earth during that time. The Earth appears to have undergone an increase in aurorae, electric storms, and cosmic radiation, causing an increase in atmospheric radiocarbon levels. The researchers linked these events to the extinction of megafauna across mainland Australia and Tasmania 42,000 years ago.
Scientists have done many studies on the breakdown during the Laschamp event. The new study focused on the period before the Laschamp event, as the magnetic fields moved across the earth to their opposite positions. The scientists found that this period was the greatest unrest in the world.
By studying the kauri tree, researchers were able to create a more detailed timeline for the Laschamp event. As Alan Cooper of the South Australian Museum further explained:
The kauri trees are like the Rosetta Stone, which helps us tie together records of environmental change in caves, ice cores and peat bogs around the world.
Can it happen today?
Some evidence suggests that a change in the orientation of the Earth’s magnetic field is already underway. Scientists have detected the northern magnetic pole that has been spotted 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 electric grid and satellites has an impact on a dystopian novel as the incoming radiation destroys our sources of power and communication. The issue of climate change adds an extra element of disaster, according to Turney:
Our atmosphere is already filled with carbon at levels that humanity has never seen before. A magnetic pole reversal or extreme change in solar activity would be an unprecedented climate change. We urgently need to reduce carbon emissions before such a random event occurs again.
In short: radiocarbon dating in kauri trees has helped researchers link the reversal of the magnetic field 42,000 years ago to environmental accidents and extinction events.
Source: A global environmental crisis 42,000 years ago
Via UNSW Sydney
