Some 42,000 years ago, Earth’s magnetic poles switched, causing the magnetic field around the planet to temporarily collapse. According to a new study, the shift was apocalyptic, sparking major climate shifts filling the skies with electrical storms, widespread auroras, and cosmic radiation. The researchers even argue these major climate shifts and may have had a decisive role in the extinction of the Neanderthals and the giant megafauna that once roamed Australia.
It’s easy to assume that Earth’s magnetic poles are stable — north is north and south is south. However, the magnetic poles can wander several kilometers every year, and based on geological records, it appears that Earth is long overdue for a total pole shift. This process is generally thought to be guided by the movement of the magnetic "blobs" of molten material swirling around the planet's interior.
An especially significant change in the Earth's magnetic field is known as the Laschamps event, which occurred around 42,000 years ago. When the poles flipped, the magnetic field temporarily collapsed and remained weakened for around 1,000 years. To understand how this magnetic field collapse affected life on Earth, scientists at the University of New South Wales and the South Australian Museum looked at rings on the ancient kauri trees in New Zealand, which have been preserved in sediments for over 40,000 years.
They discovered clear signs of a global environmental crisis. As reported in the journal Science, the tree rings revealed a substantial spike in atmospheric radiocarbon levels 42,000 years ago. This was most likely the result of Earth losing much of its magnetic field, a highly effective shield against cosmic radiation, allowing more extreme cosmic radiation to reach Earth’s atmosphere.
The team suggests that this had a hugely damaging effect on the natural world and could potentially explain some of the major extinctions that occurred around this time.
“The impacts of this event were marked and global, and may have been pivotal to our evolutionary story. The coincidence between the timing of the Laschamps event and the extinction of the Neandertals and Megafauna in Australia is remarkable and highlights the global scale of this event,” Professor Chris Fogwill, Director of Keele’s Institute for Sustainable Futures, said in a statement.
“If a similar event happened today, the consequences would be huge for modern society. Incoming cosmic radiation would destroy our electric power grids and satellite networks," added Professor Alan Cooper, co-lead author from the South Australian Museum.
This is just one of many theories on why Neanderthals went extinct. Others have speculated it was a result of competition with Homo Sapiens, inbreeding, falling fertility rates, and other manifestations of climate change. It’s fair to argue that it was, in fact, a combination of all these factors, including a catastrophic magnetic pole collapse.
Since this event occurred 42,000 years ago, the researchers have named it the “Adams Transitional Geomagnetic Event”, as a nod to novelist Douglas Adams and his book The Hitchhiker’s Guide to the Galaxy, in which the number 42 is the answer to the great question "of life, the universe, and everything.”