New study links ancient solar storms to increased radiocarbon in tree rings at University of Oulu

A new study reveals that signs of ancient solar storms can be identified in tree rings. Solar storms occur when particles and plasma ejected from the Sun collide with the Earth’s atmosphere, leading to an unusual increase in a form of carbon known as radiocarbon.

Researchers at the University of Oulu have found that significant amounts of radiocarbon accumulate in the annual growth rings of trees during solar storms, amounts described as substantial compared to typical levels. Using these anomalous radiocarbon levels, scientists can now accurately date historical solar storms to the year, which aids in preparing for future storms and deepens our understanding of solar activity and physical phenomena.

Knowledge of past solar storms is crucial for anticipating future events, which can potentially damage satellite systems and power grids. Extreme solar storms are linked to long-term changes in solar activity, though the exact reasons for their occurrence remain unclear. The most visible consequence of solar storms is the aurora borealis, with the most powerful storm since 2003 occurring last May.

Ilya Usoskin, a professor involved in the study, explains that solar activity fluctuates in 11-year cycles, and we are currently at the end of one cycle, resulting in increased sightings of strong auroras worldwide. He emphasizes that while we are experiencing more intense solar storms than a few years ago, this is normal and unrelated to the extreme storms that occur approximately once every thousand years.

The increased radiocarbon levels caused by solar storms also aid archaeologists and environmental scientists in precisely dating historical sites and events. For example, the construction date of a wooden lake fortification in Latvia was determined based on changes in radiocarbon levels caused by a solar storm.