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This video shows both X-class flares from June 10, 2014. Credit: NASA/SDO/Goddard
Like we did for the other “mega” hazards, we will start with a bit of history.
On September 1st –2nd 1859, people observed one of the largest recorded geomagnetic storms due to solar activities. Beside anomalous and wide-spread auroras occurrences, telegraph systems all over Europe and North America failed, reportedly electrocuting telegraph operators. Telegraph posts threw sparks.
Solar flares, coronal mass ejections, solar Electro Magnetic Pulses, EMPs, can cause such a geomagnetic storm.
Similarly to what we did for meteorites, we will look now at the likelyhood/consequences scenarios of solar storm hazards and risks.
On July 2012 a “Carrington-class” solar superstorm missed the earth, producing no damages, as lately reported by NASA. It is likely that the average annual frequency of these events may lay at 1/200 (5*10-3) to 1/500 (2*10-3) events/year range.
Less severe storms seem to occur with a frequency of approximately 1/50 (2*10-2) events/year with widespread radio disruption.
In March 1989 a large impulse in the Earth’s geomagnetic field erupted along the U.S./Canada border. This started a chain of power systems disturbance events that only 92 seconds later resulted in a complete collapse to the entire power grid in Quebec.
In June 2013, experts from London and the United States used data from the Carrington Event to estimate the current cost of a similar event to the U.S. alone at $0.6–2.6 trillion.
Beside electric lines, transformers will be particularly vulnerable to such an event and many will take months to replace and have no redundancy available. Indeed the the purchase placement of a single extra high voltage, EHV, transformer of the 300-400MVA class has been quoted as taking up to 15 months to manufacture and test. Of course, manufacturing and testing the equipment does not mean the story ends there. The equipment will then need to be transported to site and commissioned before being put into service.
Two low-probability but high-impact events have recently stirred the attention of policymaker.
One is the potential for a massive solar storm, the other a human-caused electromagnetic pulse (EMP). The two have different likelihoods and consequences, but the mitigation would be the same.
These low-probability but high-impact events constitute a threat to critical infrastructures. As a result the White House released a National Space Weather Strategy and Action Plan and Congress is considering bills on both subjects.
Yet outside of defense-focused EMP research and hardening of certain military systems during the Cold War, efforts to assess and mitigate space weather and EMP threats to civilian infrastructure are relatively nascent.
Policymakers are now pushing for enhanced research and preparedness efforts in this domain.