No proof that geomagnetic storms 'cause health issues': experts

Multiple experts told AFP that no credible studies have proven solar storms could affect human health, contrary to false social media posts shared after a geomagnetic storm hit the Earth in May 2024. They said solar flares primarily affect technology, including potential disruptions to the power grid, GPS signals and satellite operations.

“A geomagnetic storm may occur on May 10, which may affect the human body, causing biological clock disorders, anxiety, palpitations, etc," read the caption of a post on social media platform X in simplified Chinese published on May 9, 2024.

"The geomagnetic storm will affect people's sleep, causing fatigue and drowsiness during the day, and may cause inexplicable irritability," it continued.

The post was shared with a video repeating the false claim alongside clips showing a person struggling to sleep.

The Earth was hit by a geomagnetic storm in May 2024.

The storm -- the most powerful since October 2003 -- resulted in auroras that could be seen as far as Mexico, southern Europe and South Africa when normally the dazzling phenomenon could only be seen in the poles of the Earth.

It was caused by massive explosions on the surface of the Sun that shot out plasma, radiation and even magnetic fields at incredibly fast speeds born on the solar wind.

The false claim spread widely online in China, prompting a debate about whether the storm caused sleep problems. It was shared on X here and here, and Facebook here and here.

Other posts falsely claiming that geomagnetic storms could affect the menstrual cycle surfaced were also shared on X here and here.

It was also shared on the Chinese social media app Xiaohongshu, as shown in the screenshot below:

However, scientists said there was no evidence to support these false claims.

No effect

Daniel Verscharen, associate professor of Space and Climate Physics at University College London, told AFP there was no proof that geomagnetic storms directly affect human health (archived link).

He referred to a study that claimed to have found a link between heart diseases and space weather -- possibly caused by its slight effect on medical devices such as pacemakers -- but said the findings were not proven.

"This is not confirmed and also still controversial," he said.

Dan Welling, assistant professor at the University of Michigan Department of Climate and Space Sciences and Engineering, also said he and his undergraduate students had found studies linking space weather with human health to be of poor quality with unsupported conclusions (archived link).

"None of these studies are taken seriously at this time," he said.

He added that space weather has other effects such as; bird migration; potential disruptions to the power grid; interference with radio signals; and impacts on satellite operations.

"If you are in space, or if you are flying on airplanes over the North or South Pole, there is an increase in radiation risk," he said. "However, the atmosphere protects us from this while we are on the ground."

Mojtaba Akhavan-Tafti, an assistant research scientist in Climate and Space Sciences and Engineering at the University of Michigan, also told AFP by email in May that geomagnetic storms were linked to disruption to bird migrations as they use the Earth's magnetic field for navigation (archived link).

But he said he was "unaware of any studies where the health impacts of a geomagnetic storm on the ground have been scientifically examined".

Authorities from several countries have similarly dismissed online claims that solar activities affect human health.

Chinese state media CCTV quoted Guo Jiangang, Director of China's National Center for Space Weather of the National Satellite Meteorological Center, saying that while some have suggested solar storms may affect sleep, "it has not been scientifically proven yet".

NASA also said on May 16: "Harmful radiation from a flare cannot pass through Earth’s atmosphere to physically affect humans on the ground" (archived link).

The United States Geological Survey said the Earth's magnetic field does not directly affect human health (archived link).

"Geomagnetism can also impact the electrically based technology that we rely on, but it does not impact people themselves."

AFP previously fact-checked other misinformation on the recent solar storm here and here.