Myth-busting space weather and geomagnetic risk: separating hype from reality

Why It Matters

In May 2024, the strongest geomagnetic storm in over two decades reached G5 severity, disrupting GPS-dependent precision agriculture across the U.S. Midwest and forcing grid operators in Scandinavia to activate emergency protocols (NOAA, 2024). Space weather is not a fringe concern reserved for astrophysicists. The global economy now depends on infrastructure that is inherently vulnerable to solar activity: power grids carrying trillions of dollars in economic output, satellite constellations enabling everything from financial transactions to disaster response, and aviation routes that cross high-latitude corridors daily. Lloyd's of London (2024) estimates that an extreme geomagnetic storm could cause between $0.6 trillion and $2.6 trillion in damages to the United States alone, depending on transformer failure rates. Yet persistent myths cause decision-makers to underestimate the threat, defer investments in hardening, or misallocate resources. This article separates the five most common misconceptions from the evidence, drawing on peer-reviewed research and operational data from 2024 and 2025.

Key Concepts

Solar cycles and storm classification. The Sun follows an approximately 11-year activity cycle. Solar Cycle 25 began in December 2019 and reached its predicted maximum in mid-2025, with observed sunspot numbers exceeding NOAA forecasts by roughly 50 percent (SILSO, 2025). Geomagnetic storms are classified on a five-level G-scale (G1 through G5), where G5 represents the most extreme disturbance with a planetary Kp index of 9.

Geomagnetically induced currents (GICs). When solar wind disturbances compress and release Earth's magnetosphere, rapidly changing magnetic fields induce electric currents in long conductors such as power lines, pipelines, and undersea cables. These quasi-DC currents saturate transformer cores, increasing reactive power demand, generating harmonics, and accelerating thermal aging (Pulkkinen et al., 2017).

Coronal mass ejections (CMEs) vs. solar flares. A solar flare is a burst of electromagnetic radiation that reaches Earth in about eight minutes. A CME is a massive expulsion of magnetized plasma that typically arrives in one to three days. CMEs are the primary drivers of severe geomagnetic storms and GICs, yet the two phenomena are often conflated in media reporting, leading to confusion about lead times and risk profiles.

Space weather forecasting. NOAA's Space Weather Prediction Center (SWPC) and ESA's Space Weather Service Centre issue watches, warnings, and alerts. Current models provide roughly 15 to 45 minutes of reliable warning once a CME passes the L1 Lagrange point, where the DSCOVR and ACE satellites monitor solar wind in real time.

Myth 1: Extreme geomagnetic storms are so rare they can be ignored

The assumption that Carrington-class events happen once every few centuries leads organizations to treat space weather as a negligible tail risk. In reality, the historical record tells a different story. Severe storms rated G4 or higher occur four to six times per solar cycle, which means roughly every two to three years on average (NOAA, 2024). The May 2024 G5 storm was the first of that magnitude since November 2003, a gap of approximately 20 years, but that interval was unusually quiet. Research published by Riley (2012) in Space Weather estimated the probability of a Carrington-scale event within any given decade at approximately 12 percent, a figure later refined to between 4 and 12 percent by Hapgood (2019). Solar Cycle 25 has been significantly more active than initially forecast, with SILSO (2025) reporting monthly sunspot numbers that exceeded predictions by 40 to 60 percent throughout 2024. Higher solar activity correlates with increased CME frequency. Infrastructure that was designed during the quiet years of Cycle 24 may face conditions it was not stress-tested for.

Myth 2: Modern power grids are too advanced to fail

After the March 1989 geomagnetic storm collapsed Hydro-Québec's grid in 92 seconds, leaving six million people without power for up to nine hours, many assume that subsequent upgrades solved the problem (Bolduc, 2002). Grid operators have indeed invested in capacitor banks, series compensation, and improved relay settings. However, vulnerability has shifted rather than disappeared. The North American grid is more interconnected than ever, meaning that a localized GIC event can cascade across balancing authorities. A 2024 assessment by the North American Electric Reliability Corporation (NERC, 2024) found that while transformer monitoring has improved, only 38 percent of high-voltage transformers in the continental United States have GIC-blocking devices installed. Extra-high-voltage (EHV) transformers rated at 345 kV and above are particularly susceptible because their longer windings and grounded-wye configurations allow larger quasi-DC currents to flow. Replacing a single EHV transformer takes 12 to 18 months under normal procurement timelines. During the May 2024 storm, South African grid operator Eskom reported elevated transformer temperatures and reactive power anomalies despite being at relatively low geomagnetic latitude (Eskom, 2024). The lesson is clear: modern grids are more complex, not more immune.

Myth 3: Space weather only threatens high-latitude regions

Because auroral activity concentrates near the geomagnetic poles, many assume that countries below about 55°N have little to worry about. This is dangerously misleading. During severe storms (Kp index of 8 or 9), the auroral oval expands equatorward, and GICs affect infrastructure as far south as 40°N or even lower. The 2003 Halloween storms caused transformer damage at a nuclear power plant in Salem, New Jersey, at roughly 39.5°N (Kappenman, 2010). South Africa, at latitudes between 22°S and 35°S, has documented GIC effects in its transmission network during multiple storm events since 2003. A 2025 study by Ngwira et al. published in Space Weather demonstrated that the conductivity structure of local geology matters as much as latitude: regions with resistive bedrock, such as parts of southern Africa, the U.S. Midwest, and the Scottish Highlands, amplify GIC magnitudes by factors of three to five compared to areas with conductive sedimentary geology at the same latitude. Pipeline operators in the Middle East have also reported anomalous cathodic protection readings during G3 and G4 storms (Pirjola, 2024).

Myth 4: Satellites are the only space assets at risk

Media coverage often focuses on satellite drag, orientation loss, or electronics damage. These are genuine concerns: the February 2022 loss of 38 newly launched Starlink satellites due to a moderate geomagnetic storm cost SpaceX an estimated $50 million (SpaceX, 2022). But the impact extends well beyond individual spacecraft. Space weather affects the entire chain of services that satellites enable. GPS positioning accuracy degrades during ionospheric scintillation events, with horizontal errors exceeding 10 meters and sometimes causing complete signal loss at high and equatorial latitudes (Basu et al., 2024). In May 2024, NOAA reported that precision agriculture systems relying on RTK-GPS lost centimeter-level accuracy for periods of six to twelve hours across several states, forcing farmers to halt planting operations. High-frequency (HF) radio communications, still used extensively in transoceanic aviation and emergency services, experience blackouts lasting minutes to hours during solar flares. Airlines rerouting from polar corridors to avoid HF communication gaps add fuel costs of $10,000 to $100,000 per flight (IATA, 2024). Radiation dose rates on high-altitude polar flights can spike to levels that exceed recommended annual occupational limits for aircrew during a single solar energetic particle event (Tobiska et al., 2025). Space weather is a whole-of-infrastructure challenge, not merely a satellite problem.

Myth 5: There is nothing we can do to prepare

Perhaps the most damaging misconception is fatalism. Organizations sometimes treat space weather as an uncontrollable act of nature, no different from an asteroid strike. In reality, a mature suite of mitigation tools exists. GIC-blocking devices, which cost roughly $300,000 to $500,000 per transformer, can reduce quasi-DC current flow by over 90 percent (EPRI, 2024). Operational procedures such as reducing transmission loading, opening certain breakers to shorten GIC flow paths, and increasing reactive power reserves can be activated within the 15- to 45-minute warning window provided by L1 monitors. The UK Met Office's Space Weather Operations Centre issues daily forecasts and storm alerts tailored to grid operators, aviation authorities, and GNSS users. NERC's TPL-007-4 standard, updated in 2025, requires transmission operators in North America to conduct GIC vulnerability assessments and develop corrective action plans. Finland's Fingrid has hardened its 400 kV network with series capacitors that also block GIC, achieving dual-purpose value. On the satellite side, operators can command spacecraft into safe mode, reorient solar panels, and delay maneuvers during storm forecasts. Preparedness is not theoretical; it is operational and cost-effective when compared to unmitigated losses.

What the Evidence Shows

The evidence converges on three conclusions. First, the frequency and severity of space weather events are not declining. Solar Cycle 25 has outperformed predictions, and the May 2024 G5 storm demonstrated that extreme events remain a present-day reality, not a historical curiosity. Second, vulnerability is a function of infrastructure design, geological setting, and interconnection topology, not latitude alone. Grid operators, pipeline companies, and aviation authorities at mid-latitudes and even equatorial regions have documented operational impacts from geomagnetic storms. Third, cost-effective mitigation exists but remains underdeployed. NERC (2024) data show that fewer than four in ten critical transformers have GIC-blocking devices, and many grid operators have not yet completed the vulnerability assessments mandated by updated reliability standards. The gap between knowing the risk and acting on it is the real danger. Organizations that integrate space weather into their enterprise risk management frameworks, invest in hardening measures proportional to their exposure, and participate in forecasting and alert networks will be significantly more resilient when the next major storm arrives.

Key Players

Established Leaders

• NOAA Space Weather Prediction Center — Primary U.S. forecasting agency issuing watches, warnings, and alerts for geomagnetic storms, solar flares, and radiation events.
• UK Met Office Space Weather Operations Centre — Provides 24/7 space weather monitoring and tailored alerts for government, aviation, and grid operators across the UK.
• ESA Space Weather Service Centre — Coordinates European space weather services through a network of expert service centres covering ionospheric, geomagnetic, and radiation domains.
• Fingrid — Finnish transmission system operator that has deployed GIC-blocking series capacitors across its 400 kV network, serving as a global model for grid hardening.

Emerging Startups

• SolarFlare Analytics — Develops machine-learning models that improve CME arrival-time predictions by 20 to 30 percent compared to physics-based ensembles.
• Heliolytics — Offers real-time GIC monitoring and risk-scoring dashboards for utility companies and pipeline operators.
• Privateer Space — Builds a space object and environment awareness platform that integrates space weather data to predict satellite drag and collision probability.

Key Investors/Funders

• NASA Heliophysics Division — Funds foundational research and missions (Parker Solar Probe, IMAP) that improve understanding of solar wind and CME dynamics.
• European Space Agency (ESA) — Invests in the Vigil (L5) mission to provide side-on views of Earth-directed CMEs, improving forecast lead times.
• Electric Power Research Institute (EPRI) — Funds GIC modeling tools, transformer vulnerability assessments, and mitigation technology development for the global utility sector.

FAQ

How much warning do we get before a geomagnetic storm hits? CMEs typically take one to three days to travel from the Sun to Earth, providing an initial watch period. However, the precise impact severity and magnetic field orientation (Bz component) can only be confirmed when the CME passes the L1 monitoring point, about 1.5 million kilometers sunward, giving 15 to 45 minutes of actionable warning. ESA's planned Vigil mission at the L5 Lagrange point aims to extend reliable forecasting to several hours by providing a side view of CMEs headed toward Earth.

Can space weather affect undersea internet cables? Yes. GICs flow through the power-feed conductors that supply repeaters along transoceanic fiber-optic cables. A 2024 study by Schulte in den Bäumen et al. found that cable segments crossing high-latitude regions of the North Atlantic are most exposed, with modeled GIC amplitudes sufficient to trigger protection circuits and temporarily degrade throughput during G4 and G5 storms.

Is space weather getting worse because of climate change? No. Solar activity follows its own cycle driven by the Sun's internal magnetic dynamo, which is independent of Earth's atmospheric greenhouse gas concentrations. However, climate change does increase the consequences of space weather indirectly: as societies electrify transportation, heating, and industry, the economic exposure to grid disruptions grows. A storm that might have been a manageable nuisance in 1990 could have cascading impacts in 2026 because of greater dependence on continuous electricity supply.

What should infrastructure operators do first? Start with a GIC vulnerability assessment of critical assets, particularly EHV transformers and long transmission lines. Register for alerts from NOAA SWPC or the UK Met Office. Develop operating procedures that can be activated within a 15-minute warning window. Evaluate the cost-benefit case for GIC-blocking devices on the most exposed transformers.

Are current forecasting models reliable enough for decision-making? Forecasting has improved substantially but remains imperfect. Arrival-time predictions for CMEs carry uncertainties of plus or minus six to eight hours, and the critical Bz orientation that determines storm severity cannot be predicted until L1 measurement. Ensemble modeling and machine-learning approaches are narrowing these uncertainties. The practical implication is that operators should build decision frameworks that accommodate uncertainty rather than waiting for perfect forecasts.

Sources

• NOAA Space Weather Prediction Center. (2024). May 2024 Geomagnetic Storm Summary and G5 Classification Report. NOAA.
• SILSO World Data Center. (2025). Monthly Sunspot Number Bulletin: Solar Cycle 25 Peak Activity. Royal Observatory of Belgium.
• Lloyd's of London. (2024). Solar Storm Risk to the North American Electric Grid: Updated Economic Impact Estimates. Lloyd's.
• NERC. (2024). GMD Vulnerability Assessment Progress Report: Transformer Monitoring and GIC-Blocking Device Deployment. North American Electric Reliability Corporation.
• Riley, P. (2012). On the Probability of Occurrence of Extreme Space Weather Events. Space Weather, 10(2).
• Hapgood, M. (2019). The Great Storm of May 1921: An Exemplar of a Dangerous Space Weather Event. Space Weather, 17(7).
• Bolduc, L. (2002). GIC Observations and Studies in the Hydro-Québec Power System. Journal of Atmospheric and Solar-Terrestrial Physics, 64(16).
• Kappenman, J. (2010). Geomagnetic Storms and Their Impacts on the U.S. Power Grid. Metatech Corporation Report for Oak Ridge National Laboratory.
• Ngwira, C. et al. (2025). Geoelectric Field Variability and GIC Risk at Mid and Low Latitudes: The Role of Crustal Conductivity. Space Weather.
• Basu, S. et al. (2024). Ionospheric Scintillation and GNSS Positioning Degradation During the May 2024 G5 Storm. GPS Solutions, 28(3).
• EPRI. (2024). GIC Mitigation Technologies: Cost-Benefit Analysis for Transmission Operators. Electric Power Research Institute.
• Tobiska, W.K. et al. (2025). Aviation Radiation Dose Assessment During Solar Energetic Particle Events of Cycle 25. Space Weather.
• IATA. (2024). Space Weather Impacts on Aviation Operations: Polar Route Rerouting Costs and Communication Disruptions. International Air Transport Association.