Earth’s Magnetic Field Today (Nov. 11, 2025): Equatorial Polarity Twist, South Atlantic Anomaly Expands, and NOAA Issues G2

Updated: November 11, 2025

Key points

New peer‑reviewed work finds that near Earth’s equator the magnetosphere’s large‑scale electric polarity is reversed from the long‑held view, a nuance that changes how scientists model storm‑time space weather. ^[1]
Eleven years of ESA Swarm data show the South Atlantic Anomaly (SAA) has continued to grow and evolve, with the weakest‑field region expanding and shifting toward Africa. ^[2]
NOAA’s Space Weather Prediction Center has geomagnetic storm watches in effect today through Nov. 13 (G2 today, G3 Wednesday, G1 Thursday) as multiple CMEs approach Earth. ^[3]

What’s new today

Geomagnetic storm watches (Nov. 11–13): The U.S. National Oceanic and Atmospheric Administration (NOAA) says several coronal mass ejections are expected to begin arriving later today, prompting watches for G2 (Moderate) on Nov. 11, G3 (Strong) on Nov. 12, and G1 (Minor) on Nov. 13. Forecast uncertainty remains because of how the CMEs may interact en route, but storm‑time impacts can include stronger auroras, intermittent HF radio issues, and navigation disturbances. ^[4]

Fresh research spotlighting a growing weak spot: A new study synthesizing 11 years of ESA’s Swarm satellite measurements confirms the South Atlantic Anomaly—a weak‑field zone stretching from South America toward Africa—has enlarged notably since 2014 and is evolving differently on its African and South American “lobes.” The work links this behavior to “reverse flux patches” at the core–mantle boundary. ^[5]

A subtle but important magnetospheric twist: Separate research highlights that the magnetosphere’s large‑scale dawn‑to‑dusk electric polarity flips at low latitudes—the equatorial morning side is negative and evening side is positive—while the traditional polarity holds near the poles. That refinement matters for how scientists model the transfer of solar‑storm energy into near‑Earth space. ^[6]

The South Atlantic Anomaly is growing—and changing shape

Using Swarm’s continuous vector magnetic field record from 2014.0 to 2025.0, scientists find the surface region where Earth’s field is weakest in the South Atlantic (below 26,000 nT) expanded by 0.9% of Earth’s surface area, while the minimum intensity fell by 336 nT (from 22,430 to 22,094 nT). At the same time, strong‑field regions in the north diverged: the Canadian area shrank and weakened, whereas Siberia’s strengthened and grew—consistent with the north magnetic pole’s migration toward Siberia. ^[7]

ESA’s mission update adds crucial context: the SAA is not a single block. Since 2020, weakening has accelerated southwest of Africa, driven by evolving core dynamics where some field lines loop back into the core rather than emerging outward. This deeper‑Earth behavior can steer how and where the anomaly intensifies. ^[8]

For operators in low‑Earth orbit (LEO), the SAA matters because a weaker geomagnetic shield lets more energetic particles penetrate, raising radiation exposure that can upset onboard electronics and, in worst cases, cause instrument resets or brief blackouts. Recent reporting underscores the anomaly’s growth and its eastward “lobe” toward Africa, reinforcing the operational risk calculus for satellites and even crewed missions transiting the region. ^[9]

Communities around the South Atlantic are paying attention too: regional outlets have flagged the SAA as both a scientific puzzle and a practical challenge for technology—spanning satellites, communications, and possibly animal navigation—underscoring the anomaly’s global relevance despite its geographic focus. ^[10]

Why today’s storm watches matter—and what to expect

NOAA’s G‑scale watches (G1–G5) help industry and the public gauge potential impacts. For G2 (Moderate) to G3 (Strong) conditions, effects can include enhanced auroras, intermittent HF radio degradation, satellite drag changes, and navigation or geomagnetically induced current (GIC) variability that utilities and pipeline operators monitor closely. Final outcomes depend on the CME magnetic field’s orientation when it reaches Earth. ^[11]

If skies are clear and darkness falls during peak activity, mid‑latitude observers could get an auroral show. Pilots, mariners, and high‑latitude communities know the drill—watch for advisories and be ready for minor communications or navigation quirks while the storm window persists. ^[12]

The new “equatorial polarity flip” finding, explained

For decades, a textbook view held that the magnetosphere’s large‑scale electric field points from the morning (dawn) side to the evening (dusk) side globally. New satellite observations and global MHD simulations challenge that simplicity: near the equator, the charge polarity reverses compared with polar regions. The upshot? The electric force and charge distribution are consequences—not the cause—of plasma motion, which refines how models capture storm‑time convection and energy coupling. ^[13]

Popular coverage of the study emphasizes why this nuance matters: it helps reconcile theory with space‑era measurements and may sharpen forecasts of how solar storms perturb the near‑Earth environment—including effects that ripple into navigation, communications, and radiation‑belt dynamics. ^[14]

Is a pole reversal imminent? What models say in 2025

Despite the eye‑catching headlines, a magnetic pole reversal is not considered imminent. Reversals, when they occur, unfold over hundreds to thousands of years, and current changes—though significant—don’t indicate a flip is underway now. Leading science coverage this year has reiterated that point, even as the north magnetic pole continues its modern migration toward Siberia. ^[15]

Behind the scenes, global field models used across aviation, maritime, energy, and research—most notably the International Geomagnetic Reference Field (IGRF)—were refreshed for the five‑year cycle now in effect (IGRF‑14). Those open coefficients, finalized by IAGA in late 2024, are the backbone for consistent, up‑to‑date magnetic mapping that many industries rely on daily. ^[16]

What this means for satellites, airlines, and everyday readers

Spacecraft & ISS transits: Expect continued radiation‑management protocols over the SAA (e.g., instrument safing, data gap planning). During storm windows, operators assess additional drag and radiation risks and adjust accordingly. ^[17]
Aviation & polar routes: HF radio and GNSS can be intermittently affected during stronger disturbances; flight operations routinely plan for these scenarios. ^[18]
Power & pipelines: Utilities monitor GICs during G2–G3 watches; major grid impacts are uncommon but the sector stays on heightened awareness. ^[19]
Everyone else: For most of us, the near‑term impact is limited to potential auroras at lower‑than‑usual latitudes and a better appreciation for how dynamic—and scientifically fascinating—Earth’s magnetic shield really is. ^[20]

The bottom line

Today brings active space‑weather watches and fresh peer‑reviewed insight into how our magnetic field is changing—from the fine print of an equatorial polarity flip in the magnetosphere to the big‑picture evolution of the South Atlantic Anomaly. For technology and exploration in low‑Earth orbit, this is practical news. For science, it’s a reminder that Earth’s dynamo and its space‑weather interface are still yielding surprises. ^[21]

Sources & further reading

NOAA Space Weather Prediction Center: Geomagnetic Storm Watches for 11–13 November. ^[22]
ESA Swarm mission update: Weak spot in Earth’s magnetic field is growing (SAA). ^[23]
Finlay, Kloss & Gillet (2025), Physics of the Earth and Planetary Interiors: Core field changes from eleven years of Swarm observations (open‑access PDF, detailed numbers). ^[24]
ScienceDaily (Kyoto University press summary): Magnetosphere polarity reversed at low latitudes (with links to JGR Space Physics). ^[25]
Popular Mechanics coverage: Part of Earth’s Magnetic Field Is Backward (Nov. 10, 2025). ^[26]
Live Science explainer on SAA growth and risks to satellites. ^[27]
The Independent (Nov. 11, 2025): Strange core–mantle boundary patterns linked to SAA evolution. ^[28]
NOAA NCEI: International Geomagnetic Reference Field (IGRF‑14) background and downloads. ^[29]
Agenda Malvinas (Nov. 9, 2025): The South Atlantic magnetic anomaly—global implications. ^[30]

Editorial note: This article is tailored for Google News/Discover and reflects developments available on Nov. 11, 2025 from peer‑reviewed studies, space‑agency updates, and official space‑weather forecasts.

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