42,000 years ago there was a temporary breakdown of the Earth’s magnetic field. This led to unparalleled climate change and mass extinctions of species, a new international study co-led by UNSW Sydney and the Museum of South Australia shows. This dramatic turning point in Earth’s history, mixed with thunderstorms, widespread auroras and cosmic radiation has been dubbed the ‘Adams Geomagnetic Transition Event’, or ‘Adams Event’, a tribute to science fiction writer Douglas Adams, author of the classic “Hitchhiker’s Guide to the Galaxy” where, as our readers will know, the number ’42’ was the answer to life, the universe, and everything else.
The apocalyptic event may have been instrumental in the extinction of Neanderthals and the giant megafauna that once roamed Australia.
The magnetic poles of the Earth are not stable. The difference can be several kilometers each year and, based on geological records, it appears that the Earth is already quite behind when it comes to a total pole shift.
The last time the poles were reversed, the magnetic field temporarily collapsed and remained weakened for about 1,000 years. To understand how this collapse of the magnetic field affected life on Earth , scientists looked at the rings of ancient kauri trees in New Zealand, which have been preserved in sediments for more than 40,000 years.
“Kauri trees are like the Rosetta Stone, helping us to unite the records of environmental change in caves, ice cores and peatlands around the world,” explains Alan Cooper, co-author of the work.
A perfect cosmic storm
They discovered obvious signs of a global environmental crisis, as the tree rings revealed a substantial increase in atmospheric radiocarbon levels 42,000 years ago. This is most likely due to the fact that the Earth lost much of its magnetic field, which protects us from cosmic radiation, and therefore a large rate of extreme radiation reached the Earth’s atmosphere.
“For the first time in history, we have been able to accurately date the timing and environmental impacts of the last magnetic pole switch,” says Chris Turney, study leader in the journal Science.
The researchers compared the newly created timescale with records from sites across the Pacific and used it in modeling the global climate, finding that the growth of ice sheets and glaciers in North America and the large changes in the main wind and tropical storm systems could be traced back to the Adams Event. One of his first clues was that the megafauna in mainland Australia and Tasmania went through simultaneous extinctions 42,000 years ago.
The work suggests that the Adams Event could explain many other evolutionary mysteries, such as the extinction of Neanderthals and the sudden and widespread appearance of figurative art in caves around the world.
“It is the most surprising and important discovery I have ever been involved in,” Cooper concludes.
Could this phenomenon be repeated?
That’s how it is. There is some evidence to suggest that a change in the orientation of the Earth’s magnetic field is already taking place. Scientists have tracked the wandering of the magnetic north pole more quickly in recent years than in the past. And in the last 170 years, the Earth’s magnetic field has weakened by about 9%. Cosmic radiation would accelerate climate change in an unprecedented way and destroy technological networks as many dystopian works have told in the world of fiction.
Referencia: Alan Cooper, Chris S. M. Turney, Jonathan Palmer, Alan Hogg, Matt Mcglone, Janet Wilmshurst, Andrew M. Lorrey, Timothy J. Heaton, James M. Russell, Ken Mccracken, Julien G. Anet, Eugene Rozanov, Marina Friedel, Ivo Suter, Thomas Peter, Raimund Muscheler, Florian Adolphi, Anthony Dosseto, J. Tyler Faith, Pavla Fenwick, Christopher J. Fogwill, Konrad Hughen, Mathew Lipson, Jiabo Liu, Norbert Nowaczyk, Eleanor Rainsley, Christopher Bronk Ramsey, Paolo Sebastianelli, Yassine Souilmi, Janelle Stevenson, Zoë Thomas, Raymond Tobler, Roland Zech. A global environmental crisis 42,000 years ago. Science, 2021 DOI: 10.1126/science.abb8677 (2021).DOI:https://doi.org/10.1126/science.abb8677
