A 41,000 year old piece of pollen shows that the sun scorched the Earth when its magnetic field weakened.
The Laschamps Event was a period when the Earth's magnetic poles briefly flipped and the protective field nearly vanished. Analysis of subfossil pollen from this time shows a huge spike in compounds that plants use to shield themselves from UV-B rays. This is the first empirical proof that a weak magnetic field leads directly to a bombardment of harmful radiation. This extra radiation likely put massive pressure on prehistoric life and influenced evolution. It serves as a warning for what could happen if our magnetic field continues its current decline.
Reduced geomagnetic shielding increased UV-B radiation at Earth’s surface during the Laschamps Event
EarthArXiv · 10.31223/X53N31
Exposure to excess UV-B radiation can harm organisms through DNA damage and oxidative stress, and has likely been a key ecological and evolutionary driver throughout Earth’s history. Here, we show UV-B at Earth’s surface was significantly increased during the Laschamps Event, the last major geomagnetic excursion ca. 41ka BP. During the Laschamps, we find significant and prolonged (lasting >600yrs) increases in UV-B absorbing compounds in subfossil Pinus Diploxylon pollen (e.g., 31% [95% CI 19-44