From time to time in the media, you can see warnings about geomagnetic storms or their schedule for the coming month and recommendations on how to protect yourself from their harmful effects. Fortunately, most of them have nothing to do with reality.
What is really going on?
A geomagnetic storm is rapid, albeit small, a decrease in the magnetic field on the Earth’s surface. Almost all geomagnetic storms are caused by active processes in the Sun. In order for a geomagnetic storm to occur on Earth, two conditions must be met:
- from the central part of the solar disk should come the emission of solar matter or the flow of fast solar wind in the direction of the Earth
- when this emission or flow reaches the Earth in about 2-3 days, the magnetic field in it should be directed opposite to the main magnetic field of the Earth (ie to the south)
The release of solar matter, or, more correctly, the release of coronal mass, usually occurs suddenly. One can only predict the probability of release. Fast streams, on the other hand, are fairly stable structures and can only be predicted as soon as they appear in sight. Therefore, magnetic storms can be predicted in 2-3 days for emissions (stronger storms) and in 5-6 days for fast flows (weaker storms). With the launch of another spacecraft to monitor the Sun, the forecast horizon for fast currents can be increased to 10 days. A typical magnetic storm lasts from 1 to 3 days, and its main phase, in which the magnetic field changes the most, is several hours. Therefore, the schedules of magnetic storms by the hour for the month ahead have no scientific basis.
What is affected by a geomagnetic storm?
The magnetic storm itself affects power lines, magnetic orientation systems (used, for example, in space and when drilling oil and gas wells), satellite communications, and navigation systems such as GPS. A magnetic storm is sometimes accompanied by other manifestations of space weather, which can affect the electronics of spacecraft, radio communications, and the health of astronauts and people aboard high-altitude aircraft. According to experts from the European Space Agency, the annual losses of the European Union from adverse space weather exceed 10 billion euros. At the same time, more than 7 billion euros of losses are due to the effects of magnetic storms.
And what about the deterioration of the well-being of ordinary people during magnetic storms?
Here the situation is somewhat ambiguous. It has now been established that changes in the magnetic field, similar to magnetic storms and even much stronger, do not affect humans. This is very easy to see by taking the subway. During the acceleration and braking of a subway train, the changes in the magnetic field are about 40 times greater than those during the strongest recorded magnetic storm that occurred in 1859. At the same time, subway passengers do not feel any noticeable deterioration in health.
On the other hand, there are medical statistics that show a positive correlation between the level of magnetic activity and the number of calls to doctors and ambulance calls for cardiovascular and mental illness. The reason for this correlation is currently obscure. It may be purely psychological in nature, when people, warned of possible deterioration, begin to feel bad just because of the expectation of this. I also want to remind you that correlation does not mean causation. Thus, there is currently no reason to believe that magnetic storms lead to ill health and, moreover, there is no reason to make any recommendations to reduce their impact.
The threat of space weather to people on the surface could arise in the event of a catastrophic geomagnetic storm similar to the one that occurred in 1859. But the threat is not due to the storm itself but to the failure of the power grid and other critical infrastructure. According to the Royal Academy of Engineering (UK), the restoration of power supply in the event of a recurrence of this event will take from 3 to 18 months, depending on the number of damaged transformers.
The European Union’s direct losses in energy and aviation alone from such an event are estimated at more than € 80 billion, according to the House of Commons Committee on Science and Technology. In the event of an unforeseen catastrophic geomagnetic storm, governments can only notify the public within 30 minutes until the batteries in the mobile base stations are discharged. As the experience of the Federal Emergency Management Agency (US) exercises conducted in 2016 showed, it is virtually impossible to ensure the livelihood of people in a large area in the long absence of electricity, not to mention maintaining law and order and performing basic state functions.
How likely are such catastrophes?
An event of close or larger scale almost occurred on July 23, 2012: then an extremely powerful (and unnoticed in advance) emission barely passed the Earth. According to the latest estimates of scientists, the average probability that such an event will occur within a decade is about 10%. However, this is unlikely to happen in the coming decades. The fact is that the current level of solar activity is much lower compared to the second half of the twentieth century. This low level will last at least until 2030 when the current 11-year cycle of solar activity ends. Therefore, catastrophic magnetic storms should not be expected in the next decade. This time should be used for comprehensive preparation for the next such event because it will definitely take place, the only question is when.