News – PH – Earth’s magnetic field broke before 42000 years ago and caused a massive sudden climate change

0
5

The last great geomagnetic reversal triggered a series of dramatic events that have far-reaching consequences for our planet

The world experienced before 42000 years ago, several centuries of apocalyptic conditions, triggered by a reversal of the Earth’s magnetic poles combined with changes in the behavior of the sun. This is the most important finding of our new multidisciplinary study published in Science

This last major geomagnetic reversal triggered a series of dramatic events that have far-reaching consequences for our planet. They read like the plot of a horror film: The ozone layer was destroyed, electric storms raged over the tropics, solar winds created spectacular light shows (aurors) , Arctic air rushed over North America, ice sheets and glaciers swayed, and weather patterns moved violently

During these events, life on earth was exposed to intense ultraviolet light, Neanderthals and giant animals known as megafauna became extinct, while modern humans took refuge in caves

The magnetic north pole – pointed to by a compass needle – has no permanent position.Instead, it usually wobbles over time near the geographic north pole – the point around which the earth rotates – due to movements in the earth’s core

For reasons that are not entirely clear, magnetic pole movements can sometimes be more extreme than a wobble000 years ago and is known as the Laschamps excursion – named after the village in which it was discovered in the French Massif Central

The Laschamps excursion has been recognized worldwide, most recently in Tasmania, Australia However, it has not yet been clear whether such magnetic changes had an impact on the climate and life on the planet Our new work summarizes several lines of evidence that strongly suggest that the effects were indeed global and far-reaching

To investigate what happened, we analyzed ancient New Zealand kauri trees that have been around for more than 40 years000 years ago in peat bogs and other sediments. With the help of the annual growth rings in the kauri trees, we were able to create a detailed time scale of how the earth’s atmosphere changed during this time.The trees showed a longer increase in atmospheric radiocarbon values, which was caused by the collapse of the earth’s magnetic field when switching the pole was caused This made it possible to precisely link widely geographically distributed records

“The Kauri trees are like the Rosetta Stone and help us compile records of environmental changes in caves, ice cores and peat bogs around the world,” says Professor Alan Cooper, who leads this research project

With the help of the newly created timescale, we were able to show that the tropical rain belts of the Pacific and the westerly winds of the Southern Ocean shifted abruptly at the same time, bringing arid conditions to places like Australia at the same time with a range of megafauna including giant kangaroos and giant wombats died out. Further north, the vast Laurentide ice sheet was growing rapidly in the eastern United States and Canada, while in Europe the Neanderthals were threatened with extinction

In collaboration with a computer program that simulated the global interactions between chemistry and climate, we investigated the effects of a weaker magnetic field and changes in the strength of the sun.It is important that during the magnetic switch the strength of the magnetic field dropped to less than 6% of its current value Back then, a compass would have difficulty finding the north at all

Since our planet has essentially no magnetic field, it has completely lost its very effective shield against cosmic rays, and many more of these very penetrating particles from space could make it to the top of the atmosphere.In addition, the Sun experienced several during this period “Large solar minima”, in which the total solar activity was generally much lower, but also more unstable, and emitted numerous massive solar flares that allowed stronger ionizing cosmic rays to reach the earth

Our models showed that this combination of factors had an amplifying effect. The galaxy’s energetic cosmic rays, and also enormous bursts of cosmic rays from solar flares, could penetrate the upper atmosphere, charging up the particles in the air and causing chemical changes that lead to loss caused by stratospheric ozone

The modeled chemistry-climate simulations are consistent with the environmental shifts observed in many natural climate and environmental change archives.These conditions would also have prolonged the dazzling light shows of the aurora around the world – sometimes the nights would be as bright as that We suggest that the dramatic changes and unprecedented high UV levels caused early humans to seek shelter in caves, which was the apparent sudden bloom of cave art before 42000 years around the world declared

Due to the coincidence of apparently random cosmic events and the extreme environmental changes before 42000 years around the world we have called this time the “Adams Event” – a tribute to the great science fiction writer Douglas Adams, who wrote The The Hitchhiker’s Guide to the Galaxy and identified “42” as the answer to life that Universe and Everything Douglas Adams was really up to something big, and the remaining mystery is how did he know?

Chris Fogwill, Professor of Glaciology and Paleoclimatology, Head of School Geography, Geology and Environment, and Director of the Institute for Sustainable Future, Keele University; Alan Hogg, professor, director, Carbon Dating Laboratory, Waikato University; Chris Turney, Professor of Earth Sciences and Climate Change, Director of the Earth and Sustainability Science Research Center, Director of the Chronos 14Carbon-Cycle Facility and UNSW Director of the ARC Center for Excellence in Australian Biodiversity and Heritage, UNSW, and Zoë Thomas, ARC DECRA Fellow , UNSW

This article is republished by The Conversation under a Creative Commons license Read the original article

Media Office, UNSW Sydney NSW 2052 Australia
Telephone 61 2 9385 2864, email media @ unsweduau
Authorized by the Chief Communications Officer of UNSW’s External Engagement Division Provider Code: 00098G ABN: 57 195 873 179

Earth’s magnetic field, earth, geomagnetic inversion, Neanderthal, magnetic field

News – PH – The earth’s magnetic field broke before 42000 years ago and caused a massive sudden climate change

Source: https://newsroom.unsw.edu.au/news/science-tech/earths-magnetic-field-broke-down-42000-years-ago-and-caused-massive-sudden-climate