The team made this observation after studying a band of radioactive elements, unleashed by a storm that struck the planet in 660 BC, preserved in the ice almost half a kilometre beneath the surface.
Professor Raimund Muscheler, from Lund University in Sweden, said: "If that solar storm had occurred today, it could have had severe effects on our hi-tech society".
Since evidence has pointed to three massive solar storms taking place in the last 3,000 years, the scientists plan to explore more ice core samples to better understand these odd phenomenons. Ancient ice cores, including the samples from Greenland featured in the study, could contain spikes of beryllium-10 and chlorine-36 from SPEs. With their research, the team aims to help people prepare for future giant solar storms, which could shut down global communication systems, air traffic systems, and satellites.
In 1859, a powerful geomagnetic storm-now known as the Carrington Event-caused by a coronal mass ejection hit Earth, causing widespread electrical disruptions and blackouts.
The sun is constantly sending a stream of charged particles toward Earth via the solar wind. However, when solar storms take place on the sun's surface, they can lead to a massive surge in these particles hitting Earth. Two examples of severe solar storms in modern times that caused extensive power outages took place in Quebec, Canada, (1989) and Malmö, Sweden (2003).
In the past, scientists have used ice cores to locate two other major solar storms, one which took place in 775 AD and another in 994 AD.
Big solar storms, while rare, appear to be a naturally recurring effect, said the researchers, writing in the journal Proceedings of the National Academy of Sciences.
"That's why we must increase society's protection against solar storms", he says. He argues that there is a need for greater awareness of the possibility of very strong solar storms and the vulnerability of society.
"Our research suggests that the risks are now underestimated".
While the most serious consequences for those living in 660 BC was just a stunning display or aurora borealis or australis, northern and southern lights respectively, things would be completely different for us today.