In the year 1859, the British astronomer Richard Carrington observed unusual sun spots a hitherto unknown solar phenomenon, which was accompanied by the strongest geomagnetic storm to hit Earth in the last 500 years. The damage inflicted to technical systems was of course limited in the mid-19th century, and the failure of the telegraph system was more of a curiosity than a cause for general concern. But what if this would happen today?[1]
The Carrington Event
On the following day, Polar lights and other atmospheric phenomena could be seen all over the world. In some European cities, it is said that the sky was so bright all night that one could read a newspaper on the street. The visible effects of the strongest geomagnetic storm ever in recorded history. The destructive forces of the storm however led to a partial collapse of the telegraph system. The currents induced in the lines by the storm caused sparks to fly, destroyed telegraphs and burned paper. In fact, they were so strong that messages could still be sent from telegraph stations that had already been disconnected from the power supply in order to protect them from destruction. While the damage to the telegraph system was more of a curiosity than a serious concern, a similar event today would have devastating consequences for the technical infrastructure. Cellular networks, high-voltage lines, telephone lines, satellites, GPS navigation, systems on which our high-tech society depends upon could be severely affected, if a geomagnetic storm of equal strength would strike again. The potential damage to the satellite network alone orbiting our planet is estimated between 30 to 70 billion US dollars. Since 1859 there have been several similar events albeit with much less intensity. On August 4, 1972, a geomagnetic storm disrupted telephone lines in the US state of Illinois and on March 13, 1989, another storm shut down a generator station in Quebec, Canada, leaving 6 million Canadians in the dark for 9 hours. However, none of these events got even close to the intensity of the storm known as the Carrington Event of 1859.[2]
What is a geomagnetic storm?
The magnetic fields on the sun are in a constant flux, whenever these fields become more complex, they can erupt with energy near the solar surface. These solar explosions can take the form of solar flares, coronal mass ejections, or bursts of incredibly fast charged particles that travel nearly the speed of light.[3] In consequence it is the interaction of these three primary forms of solar activity with Earth and its vicinity which cause space weather. These three forms can be defined as:
- Solar flares are rapid releases of electromagnetic energy. The emitted radiation covers most of the electromagnetic spectrum, ranging from radio waves to X-rays.
- Coronal Mass Ejections are massive ejections of billions of tons of charged particles and magnetic field from the surface of the sun.
- Solar Energetic Particle Events in which energetic particles, mainly protons but also heavy ions, are thrown out into space.[4]
Future Risks
Our current understanding on space weather and the vulnerability of modern technology to severe events is largely based on the experiences made in the last 20 to 30 years through events such as the mentioned solar storms in 1972, 1989 as well as other events. While the socioeconomic impact and its implications for the world economy are hard to predict, it is reasonable to assume that a storm similar in magnitude to the Carrington Event would result in widespread disruptions and damage to the modern electricity-based technology. Despite the lessons learned since the 1980s and the steps taken to improve the electric grids resilience, the US electric power grid remains vulnerable to disruption and damage caused by severe space weather. As technological systems become more and more complex and adaptive over time, the potential social and economic impacts of severe space weather are likely to increase.[5] The Carrington event in 1859, which was approximately four times more powerful than anything in the past 50 years,[6] would have devastating consequences for our modern society.[7] But how likely is this going to happen? According to a new study that analysed the records of Earth’s magnetic field going back to 1868, there is a 4 percent chance of at least one severe solar storm and a 0.7 percent chance of a Carrington class storm per year.[8] In 2014, a multi-disciplinary group of scientists and economists published a paper on how severe space weather could disrupt global supply chains.[9] According to the paper, the total economic impact could be as high as $3.4 trillion USD over a year, thus a severe space weather event could potentially be the worst natural disaster in modern history.[10]
Update:
A recent paper discusses, rare and extreme superflares that have occurred in 7176, 5259 BCE and 775 CE. These were identified by the analysis of concentrations of cosmogenic radionuclides in ancient tree rings. The concentration exceeds everything in previously known records. It is worth mentioning that the Kerrington event does not even register in comparable radionuclide records. The impact of the newly discovered events would be catastrophic for aircraft, satellites, modern telecommunication and computer systems.[11]
References:
Bell, T. and Phillips, T. (2008): A Super Solar Flare: https://science.nasa.gov/science-news/science-at-nasa/2008/06may_carringtonflare (20.07.2021)
Brehm, N., et al. (2021): Tree rings reveal two strong solar proton events in 7176 and 5259 BCE. Research Square. https://www.researchsquare.com/article/rs-753272/v1 (29.09.2021)
Chapman, S.C., Horne, R. B. and Watkins, N. W. (2020): Using the aa Index Over the Last 14 Solar Cycles to Characterize Extreme Geomagnetic Activity. In: Geophysical Research Letters, Vol. 47, Issue 3.
NASA (2021): Solar science https://www.nasa.gov/solarscience (20.07.2021)
National Research Council (2008): Severe Space Weather Events: Understanding Societal and Economic Impacts: A Workshop Report. Washington, DC: The National Academies Press. http://nap.edu/12507 (22.07.2021)
Oughton, E. J. (2021): The Economic Impact of Critical National Infrastructure Failure Due to Space Weather. Centre for Risk Studies, Judge Business School, University of Cambridge, Cambridge, UK.
Reinboth, C. (2009): Wie gefährlich sind koronale Massenauswürfe? Ein Rückblick auf das Carrington-Event von 1859. https://scienceblogs.de/frischer-wind/2009/04/30/wie-gefahrlich-sind-koronale-masseauswurfe-ein-ruckblick-auf-das-carringtonevent-von-1859/ (22.07.2021)
Schulte in den Bäumen, H., Moran, D., Lenzen, M., Cairns, I. and Steenge, A. (2014): “How Severe Space Weather Can Disrupt Global Supply Chains.” Nat. Hazards Earth Syst. Sci.14 (10): 2749–59. https://doi.org/10.5194/nhess-14-2749-2014 (22.07.2021)
[1] (Reinboth 2009)
[2] (Bell and Phillips 2008)
[3] (NASA 2021)
[4] (Oughton 2021, p 4)
[5] (National Research Council 2008, p 33)
[6] (National Research Council 2008, p 26)
[7] (National Research Council 2008, p 3)
[8] (Chapman, Horne and Watkins 2020)
[9] (Schulte in den Bäumen et al. 2014)
[10] (Oughton 2021, p 18-19)
[11] (Brehm et al. 2021)