Ancient French Trees Expose Largest Solar Flare in History

Over 14,000 years ago, the Earth was struck by the largest solar flare on record. However, it was only recently uncovered when the University of Leeds and Collège de France (CDF) researched sub-fossilised tree trunks in the French Alps. 

These trees held the key to the event, due to the trunks’ growth rings possessing “an unprecedented… [amount] of atmospheric radiocarbon,” CDF said. As such, scientists deduced the amount of radiocarbon found was from a large solar flare: the biggest known to humankind.

Professor Edouard Bard, Chair of Climate and Ocean Evolution at CDF, said: “this sudden increase in radiocarbon in the atmosphere was probably caused by an exceptional solar flare, the largest ever identified.” He added: “Variations in solar activity can have an impact on the Earth’s climate, but they can also cause serious technological risks.”

How The Solar Flare Was Discovered 

Researchers identified that the ancient trees within the French Alps hosted records of solar flares past. Using an AixMICADAS spectrometer at Aix-en-Provence’s CEREGE, the team examined the trunks’ annual growth rings, and measured the radiocarbon hidden within. 

From there, they pinpointed the exact year – that being, 14,300 years ago – that the solar flare hit Earth. This was done by comparing the radiocarbon results with those found in ice cores in Greenland and performing statistical analysis. 

As a result of the analysis, the researchers identified that the solar flare was the biggest Earth has ever experienced. Bard said: “it can be attributed to a Maunder type solar phenomenon linked to the modulation of cosmic galactic particles by the helio-magnetic field.”

Risks To Human Technology

Locating a solar flare of this magnitude has engendered a need to better understand “solar phenomena”, Bard said. If a similar solar storm occurred in contemporary society, it would decimate any satellite and telecommunication system in its wake. Losing such systems would stagnate Earth, due to its dependency on in-space and on-ground technology.  

Solar flares emit a high amount of particles and electromagnetic waves, making GPS navigation systems and power grids highly susceptible. According to Bard, these waves would “paralysing air, maritime, and land transport”. Therefore, Bard argues that Earth’s technological infrastructure needs to be better equipped to handle future, unprecedented, solar flares. 

Compared To Other Solar Flares In History

In Bards analysis, he noted that nine solar flares had been detected over the past 15,000 years. Comparatively, the newly discovered solar storm was 10 to 100 times more intense than the Carrington Event of 1859. Carrington was responsible for interfering with telegraph networks and bringing the Northern Lights nearer to the equator. It’s also exceptionally larger than the solar flare Quebec experienced in 1989. This event, according to Bard: “plunged the province… into chaos for several hours”.