Solar storms caused the northern lights in May, but also disrupted satellites and GPS systems. An expert is now warning of stronger storms – and recommends revising the existing scales.
Just over a month ago, violent bubbling on the sun caused the strongest solar storms in 20 years – they reached the highest level on the solar scale at G5.
Now a British space weather expert is calling for a revision of the scales in the journal “Nature”: They leave no room for once-in-a-century superstorms – even though these are a very threatening reality.
In May, spectacular northern lights captivated people across many parts of the world – the result of the currently unusually strong solar activity. However, this not only caused colorful natural spectacles, but also malfunctions in satellites, such as those of the European Space Agency ESA, and the Starlink internet connections.
In North America, farmers complained about a failure of the satellite-based navigation system GPS, as reported by the New York Times. They had to interrupt their sowing because they use the system when working in the fields.
Simple scales for a complicated phenomenon
For space weather researcher Sean Elvidge, these very phenomena illustrate a dilemma facing his field: “How can we issue and communicate effective warnings when even such a significant storm changes little in most people’s lives?” Part of the problem lies in how space weather is classified, says Elvidge, who researches at the University of Birmingham in the UK. “The current systems are simplified, space weather is not.”
According to the Max Planck Institute for Solar System Research, the strength of solar storms is given in three five-level categories: – R for radio disturbances caused by X-ray flashes – S for radiation effects caused by high-energy particles – G for geomagnetic effects caused by plasma clouds.
Such scales are invaluable, says Elvidge, in helping industry and governments understand the risk of space weather. “But they need to be overhauled,” says Elvidge, referring to the geomagnetic storm that caused the auroras in May, which was classified as G5, or extreme. “This storm was triggered by a rapid succession of at least seven coronal mass ejections,” the expert writes. “When these collided with the Earth’s magnetic field, they compressed and disturbed it, triggering geomagnetic storms.”
No room for superstorms on the scale
Elvidge explains in his opinion piece that the storm was influenced by many factors, such as the speed, mass, duration and magnetic orientation of the coronal mass ejections. It is precisely the long duration that makes the May storm an exceptional event: “If an event like the one in May, which is classified as ‘extreme,’ results in only minimal obvious disruption, how can the risks of an even stronger storm that occurs once in 100 years be communicated?”
According to the space weather researcher, such a superstorm is a looming scenario – with serious consequences, the cost of which could amount to billions of US dollars. Elvidge lists power grids, satellites, and radio signals for aviation, shipping, and emergency services as areas that such an extreme storm could affect.
To adequately convey the severity of such storms, there are already proposals, including extending existing scales or introducing new phenomena such as radiation dosing or the propagation of radio waves in the Earth’s upper atmosphere.
Elvidge himself advocates a traffic light system that quickly informs those who could be affected first: “For example, yellow space weather warnings could warn industries such as aviation and agriculture that could be affected by minor geomagnetic storms. An orange warning could prompt users such as power grid and radar operators to take preventive measures to protect their services and prepare for interruptions. A red warning would signal that dangerous space weather is expected, the potentially significant impact of which requires immediate action, and that energy suppliers, satellite operators and emergency services must immediately implement contingency plans.”
The expert suggests that space weather centers worldwide should jointly discuss and agree on a unified approach to refining space weather reports and response strategies.
“While we are at the peak of the solar cycle, it is important to recognize that space weather affects our daily lives,” Elvidge emphasizes. In fact, the Sun’s activity fluctuates in a roughly 11-year cycle. The current cycle is currently at its peak – one that lasts a few years and is accompanied by relatively many solar flares. Elvidge writes: “By refining classification and reporting systems, scientists can better align public perception with reality and ensure that we neither raise false alarms nor are caught off guard.”