Solar Storm 14,300 Years Ago Created Radiocarbon Spike, Scientists Find

Scientists have always been fascinated by the sun's influence on Earth, and many studies have been conducted on this topic over the years. A recent finding, both unsettling and important for Earth sciences, has shed new light on this relationship.

In this new study, an international team of scientists identified a substantial rise in radiocarbon levels by examining ancient tree rings found in the French Alps. By examining ancient tree rings, scientists have unearthed evidence of an exceptionally powerful solar storm that struck Earth approximately 14,300 years ago. Remarkably, these findings indicate that it may have been one of the most colossal solar storms ever documented.

According to a news release, a similar solar storm today would be catastrophic for modern technological society, potentially wiping out telecommunications and satellite systems, causing massive electricity grid blackouts, and costing us billions of pounds. The academics are warning of the importance of understanding such storms to protect our global communications and energy infrastructure for the future.

The collaborative research, which was carried out by an international team of scientists, is published today (October 9) in The Royal Society's Philosophical Transactions A: Mathematical, Physical, and Engineering Sciences and reveals new insights into the sun's extreme behavior and the risks it poses to Earth.

A team of researchers from the College de France, CEREGE, IMBE, Aix-Marseille University, and the University of Leeds measured radiocarbon levels in ancient trees preserved within the eroded banks of the Drouzet River, near Gap, in the Southern French Alps.

The tree trunks, which are subfossils-remains whose fossilization process is not complete-were sliced into tiny single tree rings. Analysis of these individual rings identified an unprecedented spike in radiocarbon levels occurring precisely 14,300 years ago. By comparing this radiocarbon spike with measurements of beryllium, a chemical element found in Greenland ice cores, the team proposes that the spike was caused by a massive solar storm that would have ejected huge volumes of energetic particles into Earth's atmosphere.

"Radiocarbon is constantly being produced in the upper atmosphere through a chain of reactions initiated by cosmic rays. Recently, scientists have found that extreme solar events, including solar flares and coronal mass ejections, can also create short-term bursts of energetic particles that are preserved as huge spikes in radiocarbon production occurring over the course of just a single year," said Edouard Bard, Professor of Climate and Ocean Evolution at the College de France and CEREGE and lead author of the study.