Mpho Tshisaphungo may be a scientist steeped in maths and physics, but she is not the cold, cerebral, dispassionate kind. You can tell by the way she interrupts her presentation on the intricacies of sunspots to exclaim: “Just look at this CME, it’s so beautiful!”
Tshisaphungo is head of the space weather centre that the South African National Space Agency (Sansa) runs in Hermanus, where she and her team devote much of their time to monitoring the sun and the various ways it can bring humans joy and misery.
It’s the misery part that takes precedence — due to that miserable science, economics — and coronal mass ejections (CMEs) are a major culprit. Explosions of magnetic plasma released by solar flares, they hurtle towards the Earth where, depending on their strength, they can disable satellites, send GPS signals haywire and cause power grid blackouts.
And they’ll look gorgeous while they’re doing it. The video that made Tshisaphungo so happy, taken by a Nasa satellite dedicated to monitoring the sun, showed the waves of plasma bursting like a sci-fi fountain from a highly active sunspot early in October. Once the energy from that CME reached us a couple of days later, in the form of a geomagnetic storm, it caused spectacular polar lights displays, including an aurora visible in South Africa. It was the second such light display for South Africans this year, following what was dubbed the “Mother’s Day” storm in May.
Because of the configuration of the Earth’s magnetic field, CME energy is channelled to the north and south poles, only affecting the mid-latitudes when it arrives with unusual force. And that happens more often when the sun nears the peak of its 11-year storm cycle, known as “solar maximum”, which it is doing now.
“We are interested in space weather because it can impact our technological systems and we are very dependent on technology,” Tshisaphungo tells the FM. “If I want to find out where to go now, I just put my GPS on; we trust the technology so much but sometimes these technologies can be affected by space weather.”
A 2017 report by the University of Cambridge Judge Business School, the British Antarctic Survey, the British Geological Survey and the University of Cape Town (UCT) estimated that an extreme storm could cost the US economy $41.5bn a day.
The Hermanus team includes 11 space weather forecasters, a niche job if there ever was one, who monitor the sun 24/7 in a dimly lit room, gazing at a wall filled with screens showing real-time images from satellites and graphs of solar activity.
They try to predict how this activity will translate into impacts on Earth.
“Space weather is a new science, and we are now where terrestrial weather science was about 100 years ago,” says Daleen Fouché, communications practitioner at the Hermanus centre. “So we still have a lot to learn.”
The problem is that though it’s easy to record what happens on the surface of the sun, there’s no way of telling what changes CME energy will go through during the intervening 150-million kilometres to our planet. So it’s hard to say exactly when it will arrive, and how strong it will be when it does.
“We use our models to say ‘this is what is projected to happen’ ... People like to know with certainty, but unfortunately certainty is not something we can give them,” Fouché says.
“For the average person on the street, these storms come and go without you even noticing them, most of the time. It really is industries using these technological systems that need to take note ... But as we move further into a technology-reliant world, [space weather] will start affecting more and more people.”
The mother of all storms
The scientists, engineers, aviation authorities and insurance companies who worry about solar storms speak in hushed tones of “the Carrington event”, an extreme solar superstorm in 1859 named for the British astronomer who recorded it, Richard Carrington. Estimated to have released as much energy as 10-billion 1Mt nuclear warheads, it wreaked havoc on the state-of-the-art communication system of the time — the telegraph.
Fortunately no-one relied on GPS or smartphones in the mid-19th century, and Eskom had yet to be imagined. But another legendary CME impact in 1989 became known as “the Quebec storm” because it destroyed transformers, tripped circuit breakers and caused a nine-hour blackout in the Canadian province.
The energy from a CME can create geomagnetically induced current (GIC) in the Earth’s crust, which will pass into anything nearby that has attractive conductivity such as Eskom’s long transmission lines (and oil pipelines and copper subsea communication cables).
If Eskom struggles to survive a rainstorm that gets its coal wet, South Africans will be forgiven for wondering what a dose of GIC might do. In fact, we already know: in 2003 the strong “Halloween storm”, so named because it peaked at the end of October, sparked a series of events that culminated within months in several large transformer failures.
Trevor Gaunt, professor emeritus in the department of electrical engineering at UCT, explains: “GICs find their way into the power system through the [grounded] neutrals of transformers, typically, and circulate in the transmission network … The GICs are very low frequency so the transformer core tends to build up a saturation over a period.”
The result is heating, which can initiate damage to the insulation. “When the storm subsides, that weak spot might continue to deteriorate,” Gaunt, a co-author of the 2017 study into economic impacts, tells the FM. “If you have a problem with your car, and you don’t do something about it, eventually it becomes a big problem.”
But the good news, Gaunt says, is that Eskom and other utilities around the world have learnt their lesson and are upgrading their equipment so it is far more resistant to GIC damage.
“Now that we know to look for it, I don’t think Eskom will have that problem again … We also understand that reducing the load during a geomagnetic disturbance creates a little bit of headroom for transformer operating conditions.”
Eskom echoes Gaunt’s optimism.
“From the recent events, even when the storm severity was Kp8 [near the top of the range], the grid remained stable, and no issues were encountered,” an Eskom spokesperson said in an e-mail to the FM. This was the Mother’s Day storm. “No incidents were reported. The plant was assessed and found to be healthy post the storm.”
Eskom has collaborated with the Electric Power Research Institute in the US, whose work “showed that the blackout of our power grid because of a solar storm is highly unlikely”.
Don’t get on a plane
But if Eskom is safe, satellites and GPS are not. According to a 2016 report by the UK’s Civil Aviation Authority (CAA), a Carrington-scale storm would temporarily disable one in 10 satellites — and there’s no guarantee that an even stronger storm will not occur.
But even relatively mild storms degrade the accuracy of GPS systems, which have become essential for everyone from surveyors and Uber drivers to ship captains. The Mother’s Day storm caused havoc among farmers in the northern states of the US, whose hi-tech tractors now depend on GPS to tell one row of mealies from another.
It’s not only knowing where you are — GPS satellites equipped with atomic clocks are now the global standard for accurate time signals and synchronisation, which are crucial for, among other things, the smooth operation of financial transactions.
You might not have to hide under your bed when a geomagnetic storm hits, but you should think twice about catching a plane — flights can be rerouted, delayed or cancelled, and people flying on polar routes can be subjected to unusually high levels of radiation.
One of the main problems for pilots is that a solar storm generates energy that can knock out the high-frequency radio communications they use to communicate with the ground. This affects the entire side of the Earth facing the sun and the energy arrives within eight minutes, so no warning is possible.
It was to address the risks to aviation that Sansa set up its space weather forecasting centre, which has been operating since 2022.
“The International Civil Aviation Organisation [ICAO] has made it mandatory that all flights need to include space weather on their flight plans,” says Fouché. “So we started imagining this project … and we took [this centre] from a 9-5 limited research capability to a fully fledged 24/7 operational capability in three years.”
The Hermanus forecasting centre is one of only five in the world accredited by the ICAO.
“The aviation industry should ensure that the [space weather] risk has been assessed and mitigations are in place,” says the 2016 CAA report. “The issue is not will a solar superstorm occur, but when will it occur?”
Says Tshisaphungo: “The Carrington event was the mother of all storms. If we get one like it now, then we are going to be in trouble. Everything would stop working. We would go back to the Stone Age.”
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