A new study reveals that a reversal of the Earth’s magnetic poles 42,000 to 41,000 years ago could have led to environmental crises that led to mass extinctions. The period is called The Laschamps trip and the research used accurate carbon dating from ancient tree fossils to study its effects.
The team details how they created an accurate radiocarbon record during the “Laschamps geomagnetic reversal about 41,000 years ago in the rings of swamp trees in New Zealand.”
“This record reveals a substantial increase in the carbon-14 content of the atmosphere, culminating in the period of weakening of the intensity of the magnetic field preceding the polarity switch.” The team concluded that “the minimum geomagnetic field caused substantial changes in the concentration of atmospheric ozone that led to the global climate and synchronous environment”, their model investigating the consequences of this event.
The researchers also pointed out that it is the first study of its kind to determine a link between pole reversal and environmental change. To conduct the study, Cooper and his team used cross-sections from four ancient trees recovered from a swamp in Ngāwhā Springs in northern New Zealand and tested them for carbon-14.
The team then simulated how a changing magnetic field could affect atmospheric patterns. Their results indicated that the increase in charged particles entering the atmosphere would also result in an increase in the production of atmospheric oxides of hydrogen and nitrogen.
These molecules would consume ozone, preventing stratospheric ozone from protecting Earth’s inhabitants from ultraviolet radiation. These changes would also disrupt sunlight from being absorbed into various layers of the atmosphere, leading to widespread cooling of the planet.
However, although the research is generally interesting and solid, researchers rely a little too much on hypotheses. It’s like looking for anything that happened 42,000 years ago, which could be related to changing environmental circumstances.
Finally, what happened 42,000 years ago is still unknown. But the paper could inspire more research to examine the principles behind these mass extinctions. The study was published in the journal Science.
DISCLAIMER: This article has been updated to contextualize the limitations of the research and its conclusions.