In May 2024, the strongest geomagnetic storm in two decades pushed the Northern Lights far enough south to become visible across much of the UK and beyond. Now, a study that appeared in Royal Society Open Science reveals that the incident also exposed important gaps in how the UK monitors and prepares its power grid, satellites, and aviation for future extreme space weather.
The storm reached a G5 rating, which is the highest level on the geomagnetic storm scale used by NOAA, as a result of five coronal mass ejections reaching Earth within a period of two days. Researchers with the Space Environment Impacts Expert Group (SEIEG) stated that although the storm caused only relatively minor disruption, it revealed shortcomings in the UK’s capacity to monitor and prepare for more severe space weather events.
The SEIEG then made 14 recommendations to the UK government addressing matters such as grid monitoring, satellite operations, and space weather forecasting. Richard Horne, chair of SEIEG and head of space weather at the British Antarctic Survey, recently gave a presentation on the findings at the Royal Astronomical Society’s National Astronomy Meeting in Birmingham.
A Storm That Tested the Limits
Researchers estimate that the May 2024 storm was a one-in-13-year event. By contrast, a Carrington-class storm, like the 1859 event that defines the standard for extreme space weather, has about a 1% chance of occurring in any given year. This means that a much more disruptive storm is still possible. The SEIEG report uses the 2024 storm as a practical example to assess how prepared the UK is for a more severe event.
“The Northern Lights were the most visible sign of the May 2024 storm, but they were only one part of a much broader space weather event that tested the UK’s critical infrastructure. The storm highlighted where we need better monitoring, better forecasting and more research so we’re prepared for a more severe event in the future,” Horne said.
The Blind Spot in Britain’s Power Grid
Geomagnetic storms create electric fields at Earth’s surface that can drive geomagnetically induced currents (GICs) through long conductive systems, including power transmission networks. High levels of GICs can overheat transformers, disrupt their normal function, and in severe cases cause damage that may lead to failures across parts of the power grid.
Currently, there are no GIC monitors in operation in England or Wales. The SEIEG report recommends establishing a network of monitors to assess how much current various transformer designs can tolerate before sustaining damage.
New Zealand as the Model
The report cites New Zealand as an example of effective monitoring. Since it is at a similar geomagnetic latitude, the country faces similar space weather risks, and its grid operators monitor around 93 transformers across 28 substations. Unlike in England and Wales, where monitoring is absent, these operators have verified their models using actual measurements and implemented operational mitigation procedures during the May 2024 storm.
Crowded Skies, Rising Risk
The storm also affected satellites in orbit. Almost 5,000 satellites adjusted their orbits during the storm. Satellites licensed in the UK saw their number of collision warnings rise by 35%. Since there are now so many objects in low-Earth orbit, a serious storm could raise the risk of collisions, possibly resulting in debris and causing additional incidents.
Preparing for Future Storms
SEIEG also recommends improving forecasts of coronal mass ejections and solar energetic particle events to provide two to three hours of warning before severe geomagnetic storms reach Earth. Improved forecasts could allow grid operators, satellite controllers, and airlines to take protective measures before severe geomagnetic storms arrive.
“One of the biggest lessons from the May 2024 storm is that we still have important gaps in our monitoring and understanding of how severe space weather could affect UK infrastructure,” said Horne. “We were fortunate that this was not a one-in-100-year event. We now have an opportunity to strengthen our monitoring, improve our forecasts and make sure the UK is better prepared before a much larger storm occurs.”
The 14 recommendations are now under review by the UK government. Whether these steps will be taken before a Carrington-scale storm occurs remains uncertain. With this extreme class of storms remaining a realistic possibility, the researchers argue that improving monitoring and forecasting now could reduce the impact of a future extreme event.
Austin Burgess is a writer and researcher with a background in sales, marketing, and data analytics. He holds an MBA, a Bachelor of Science in Business Administration, and a data analytics certification. His work focuses on breaking scientific developments, with an emphasis on emerging biology, cognitive neuroscience, and archaeological discoveries.