How Solar Storms Threaten Your Peanuts: Inside a $100M Risk to U.S. Peanut Farming

How a Solar Storm Can Put a Peanut Harvest at Risk

With solar activity expected to remain elevated for the next few years, stronger geomagnetic storms are possible. The northern lights may grab headlines, but the invisible interference with satellite navigation can ripple through modern agriculture — and, in extreme cases, threaten millions of dollars of peanut production.

What happened in May 2024

On May 10–11, 2024, the first G5 geomagnetic storm in more than two decades — dubbed the "Gannon Storm" — produced spectacular auroras and disrupted GPS guidance across parts of the U.S. Farmers reported autoguidance systems on tractors jolting, freezing or steering off course. For peanut growers in the southeastern United States, that disruption hit at a particularly sensitive moment: peak planting season.

Why peanuts are especially vulnerable

Peanut plants form pods underground, and once the canopy closes the rows are no longer visible. That makes peanut farming unusually dependent on ultra-precise positioning. Farmers use RTK (real-time kinematic) GPS, which delivers sub-centimeter accuracy and retains that precision over months — essential for aligning planting and later digging operations.

"It's imperative that we measure the planting progress, or the planting path with RTK GPS," agricultural economist Terry Griffin told Space.com. "Sub-centimeter accuracy is really important and RTK provides us that accuracy months or even years later."

If RTK signals degrade during planting or harvesting, farmers may not be able to follow hidden rows. Griffin estimates that losing RTK precision can reduce peanut yields by at least 11% because pods are missed during digging.

Economic stakes and timing

Griffin's modeling — currently under peer review — shows that mistimed decisions during GNSS (Global Navigation Satellite System) outages could put more than $100 million of southeastern U.S. peanut production at risk. In a worst-case timing scenario he estimates nearly 262 kilotons (262,000 metric tons; roughly 577 million pounds) of peanuts for human consumption could be lost.

The severity of impact depends strongly on timing. A major geomagnetic event during a narrow planting window can force farmers into a painful choice: continue planting without RTK and risk misaligned digging months later, or stop planting and lose vital growing time. Peanuts rely on accumulated warmth — "heat-unit accumulation" — to reach development milestones, so delays can cause a "biological penalty."

A practical solution: duration "nowcasts" and in-cab warnings

Right now, farmers often don't know whether a GPS outage will last hours or days. To reduce uncertainty, Griffin proposes short-term duration "nowcasts" that predict how long RTK-level GPS will remain degraded. Such forecasts could guide the decision to plant or wait.

Griffin's analysis suggests accurate space-weather nowcasts could be worth about $20 million per year for Georgia and roughly $33 million for the broader Southeast — roughly 5% of the peanut crop value in that region, and more than double the typical economic value attributed to terrestrial weather forecasts.

He also recommends integrating space-weather alerts into the same weather apps farmers already use and adding a simple in-cab alert to indicate when GPS data are unreliable.

Preparing for future storms

The May 2024 event was a wake-up call: modern precision agriculture had not yet experienced a strong solar storm in the era of widespread RTK use. Solar Cycle 25 brought the strongest geomagnetic storm in over 20 years and offered the first real-world stress test for GPS-guided planting and harvesting.

Researchers hope new space-based assets — including NOAA's SWFO-L1 observatory, NASA's IMAP mission and the Carruthers Geocorona Observatory — will improve monitoring and forecasting. If those observations can be translated into usable short-term guidance for farmers, agriculture could gain a valuable new tool to minimize crop loss during GNSS outages.

"If we can make forecasts that are usable for end users, that's going to be a huge step forward," Griffin said.