Ebene News – GB – The reversal of the Earth’s magnetic field linked to extinctions 42,000 years ago

By Karina Shah

Earth’s most recent magnetic field reversal may be 42,000 years old, new analysis of fossilized tree rings finds This magnetic pole reversal has been devastating, creating extreme weather conditions and possibly leading to be at the extinction of large mammals

Earth’s magnetic field stretches out into space and is more concentrated at the north and south poles These magnetic poles occasionally wander and reverse every 200,000 to 300,000 years, but we have little evidence of how this affects our planet

Alan Cooper of the South Australian Museum in Adelaide and his colleagues have now provided answers.They have proposed the most accurate date to date of the last reversal of Earth’s magnetic field, the Laschamp event, which, according to them, occurred between 41,560 and 41,050 years and lasted less than 1000 years

The team calculated this estimate using radiocarbon analysis of tree rings from an ancient fossilized kauri (Agathis australis) preserved in the wetlands of northern New Zealand

“The tree lived throughout the Laschamps and we used the displacement of the radiocarbon, carbon-14, through the atmosphere to detect exactly when the magnetic field collapsed,” says Cooper

Earth’s magnetosphere – the region around the planet dominated by Earth’s magnetic field – weakens as magnetic poles reverse Cooper and his team estimate that Earth’s magnetic field was only 6% of current levels during the Laschamp event

When the magnetic field weakens, cosmic rays enter the atmosphere and transform carbon atoms into a radioactive form called carbon-14 By measuring the levels of carbon-14 in each tree ring of the kauri tree, they were able to accurately date the Laschamp event

They then used climate modeling to find that several major changes coincided with the Laschamp event.The weakened magnetic field allowed more ionizing radiation from solar flares and cosmic rays from space to reach the Earth

“They damage the ozone layer and the ultraviolet light comes in at very high levels,” Cooper says This is said to have caused extreme weather conditions including lightning, high temperatures and a lot of sunlight – to which organisms may have struggled to adapt

“These extreme environmental changes may have caused, or at least contributed to, extinction events, including those of large mammals in Australia and Neanderthals in Europe,” says Paula Reimer of Queen’s University in Belfast, who was not involved in the research The megafauna in Australia and Tasmania – giant prehistoric mammals that existed in the Late Pleistocene – and Neanderthals in Europe disappeared around the same time as the magnetic pole reversal there 42,000 years old

The North Pole has moved spasmodically over the last century, drifting about a mile a year, says Cooper “It doesn’t necessarily mean it’s going to happen again, but if it did, it would be absolutely catastrophic He said

Earth, Earth’s magnetic field, geomagnetic inversion, magnetism, swamp kauri, Laschamp event

Ebene News – GB – The shift in the Earth’s magnetic field linked to extinctions 42 years ago 000 years

Source: https://www.newscientist.com/article/2268520-earths-magnetic-field-flipping-linked-to-extinctions-42000-years-ago/