Severe Space Weather: Solar Storms - National Research Council - 2010
Electromagnetic and particle radiation emitted by the sun are the primary causes of space weather affecting the Earth. Radiation carried by solar flares (caused by sudden releases of magnetic energy from the sun’s corona) and coronal mass ejections (CMEs) (large-scale, high-mass eruptions of plasma from the sun’s corona) can be harmful to biological systems and cause disruptive currents in the Earth’s ionosphere and magnetosphere, resulting in geo-magnetic storms.
The frequency and intensity of solar flares and CMEs peak and trough according to the eleven-year solar activity cycle (i.e. there are, on average, eleven years between solar maxima, when the sun is most active in producing flares and CMEs). At a solar maximum (the next one is predicted by NASA to occur in April/May 2013) a CME reaches Earth’s orbit about once every five days and an average of 12 CME-induced geo-magnetic storms can be expected annually on Earth [Jansen et al., 2000]. History tells us that very large storms are low probability events – the largest storm on record, the ‘Carrington event’ of 1859, was caused by a massive CME and a storm of this magnitude is probably a once-in-500-years event. Storms of half this intensity can be expected every 50 years or so [Odenwald and Green, 2008]. Severe solar storms are therefore low probability, high impact events.
These space weather events are a natural source of risk and are nothing new – such events have been observed for as long as humankind has been watching the skies. However, while it may not be possible to classify the risk as emerging, it is certainly the case that human societies (mainly in the sense of built infrastructures and economies) exhibit emerging vulnerabilities to space weather.
Where radiation hazards are concerned, although the Earth’s atmosphere shields people on the ground from harmful doses of radiation, the advent of the ‘space age’ and the increased frequency of space missions and of commercial flights means that more people are now at risk of exposure to higher doses of radiation. Major airlines already reroute flights away from the poles during solar storms (high northern latitudes entail higher radiation exposure) and NASA takes precautions to protect astronauts in space [NOAA, 2006].
The greatest vulnerabilities, however, and the ones with the potential to have the largest adverse impacts on society, are related to technologies that are sensitive to disruptions in the Earth’s ionosphere and magnetosphere. Over the course of the last hundred years, technological advances have steadily increased the importance of communication technologies, transport networks, and the power and interconnectedness of electricity grids (not to mention their interdependence with other infrastructures). Such progress has “inadvertently and unknowingly escalated the risks from geomagnetic storms” [Brooks, 2009].
These vulnerabilities stem from the fact that charged particles from the sun can:
- cause physical damage to orbiting satellites and spacecraft by damaging microchips, solar cells, accelerating orbital decay, etc;
- disturb electromagnetic interactions in the ionosphere and thus severely interfere with GPS navigation signals and the propagation of radio waves; and
- cause variations in Earth’s geomagnetic field that can induce currents – known as geo-magnetically induced currents (GICs) – to flow between conductors on the ground (for example, between transformers in a power transmission network or along buried pipelines).
GICs in particular pose important risks to modern society because of the wide range of essential infrastructures that could be affected. Voltage fluctuations in deep-sea cables could disturb telecommunications networks; transformers in electric power systems may be saturated by GICs, causing emergency shutdowns; oil and gas pipelines can suffer corrosion; and, rail signalling systems can be disturbed.
Although vulnerabilities to space weather do not receive a lot of press coverage, there is precedent (confirmed or strongly suspected) for all of the above-mentioned occurrences [Jansen et al., 2000]. To take one example, in March 1989, a solar storm caused a GIC that resulted in the failure (within 90 seconds) of the entire Quebec-Hydro power grid in Canada, leaving six million people without electricity for up to 9 hours. In the event of a bigger solar storm – say, as big as the Carrington event of 1859 – it would not be hard to imagine that widespread electric power blackouts could occur as electricity transformers overheat and fail.
As damaged transformers cannot be repaired in the field and must be replaced with new units, which have manufacturing lead times of twelve months or more, long-term blackouts and chronic shortages may persist for some time. Transportation, banking and finance systems, communications and government services would cease operation or be severely disrupted. Drinking water and fuel supplies would soon run dry as pumps from water reservoirs or underground tanks at fuelling stations stopped working. Back-up generators would assure power to pivotal sites such as hospitals, but only for a few days. And, perishable foods and medications would soon spoil, creating shortages of vital supplies.
Extreme as it may sound, this is the kind of scenario imagined in a recent study by the US National Research Council [NRC, 2008]. This study estimated that a severe solar storm could lead to societal and economic costs for the United States of USD 1-2 trillion in the first year alone, and that complete recovery may take from four to ten years.
Of course, there are many factors that can act to amplify or attenuate a society’s vulnerability to space weather events… although not all of them are necessarily controllable.
Perhaps the most obvious factor is scientific unknowns – the knowledge that we have of the natural systems involved (of solar chemistry or atmospheric physics) and of the nature and extent of where our vulnerabilities lie is incomplete While we know a lot about solar chemistry and understand the processes by which solar flares and CMEs are formed, there are still important unknowns due, in large part, to the complexity of the systems involved (complexity of solar chemistry, of the interplanetary environment between the earth and the sun, etc). Despite the fact that the eleven-year solar cycle helps predictability of space weather to some extent, modelling is still not accurate enough to give more than a few hours of qualitative warning of a solar event [Cole, 2003]. Although most flares and CMEs occur at solar maxima, large magnetic storms have also occurred at solar minima and, indeed, the largest flare in modern times occurred during a solar lull in 2006 [Turner, 2009]. Deep,
structural uncertainty provides obstacles to accurate forecasting of solar events. Vulnerabilities are hard to gauge with accuracy, for a number of reasons. First, because damaged satellites and other space electronics cannot be recovered, the true cause of failures cannot be established. Added to this there is sometimes the problem of information asymmetries between scientists and satellite owners, who are often unwilling to divulge the number and causes of failures they have suffered for reasons of security and competitiveness [Odenwald, 2001]. Second, many technologies on the ground have simply never been put to the test, as previous experiences of large solar storms occurred in a world that was less technology-dependent; and finally, it is hard to determine the effectiveness of any shielding measures, as “experts don’t fully know what the sun is capable of spewing out” [Turner, 2009].
Another element that is vital in defining the scope and scale of risk from solar storms is to do with situational context and varying susceptibilities to the risks posed by solar storms – geography, geology, wealth and development all strongly influence a society’s level of susceptibility. Because the effects of solar storms are centred on the Earth’s magnetic poles, regions close to these poles are more at risk. In practice, North America is the most exposed region because it is close to the North magnetic pole (which tilts towards it). The South Emerging Risks: Solar storms, October 2010 magnetic pole, by contrast, is far from inhabited land off the coast of Antarctica. Not only is North America close to the North magnetic pole, but it is also a wealthy and highly developed region, heavily reliant on technology and with a dense power grid infrastructure. The geology of the region amplifies risks from solar storms, too, as much of the power grid is located in areas of igneous rock, which has a higher electrical resistance to GICs, thus making it more likely that the GICs will flow through power transmission lines above ground [Kappenman et al., 1997].
The complexity and high connectivity of infrastructure such as the North American power grid creates an important challenge for risk governance – many other systems rely on electricity, and so the consequences of a power black-out will have widespread effects on society. Thus, for each system or technology at risk, secondary effects in other areas must also be considered. Large networks with many interdependencies are obviously much harder and more expensive to protect from the effects of solar storms. Tight coupling and a resulting loss of safety margins in these networks can amplify the consequences of damage from a solar storm. Building resilience and redundancies that reduce the consequences of solar storm damage is one possible way to mitigate risk; however the potential gains (reduction of harmful effects) must be carefully weighed against the costs and difficulty of the task. Whether or not building redundancies and resilience is the chosen governance alternative depends heavily on how risks are prioritised and how trade-offs are dealt with. The US National Oceanographic and Atmosphere Administration (NOAA), which has satellites in geosynchronous orbit to monitor the US, has an on-orbit spare in place (as well as spares in production) for its most critical satellites in case of damage from space weather [Turner, 2009]. As in this case, when national security could be endangered due to failures, the cost of creating redundancies may be judged worthwhile. However, in the case of a commercial power company, this solution might not be so appealing. Although resilience can be built by coupling the systems in a loose way such that cascading failures are stopped, rebuilding or reorganising an existing system may be complicated and expensive. And while it is possible to install devices to block the flow of GICs, such devices are also complicated and expensive to install across a large area. Given the low probability that a storm big enough to cause widespread damage will occur; companies may prefer to avoid such a costly (and potentially redundant) investment and instead rely on contingency procedures.
Contingency procedures – such as reducing system load or disconnecting system components of a power grid – are another method of reducing the harmful consequences of solar storms. However, there are temporal complications that may reduce the efficacy of these solutions, the problem being that implementing contingency procedures almost always requires early warning capabilities… with one hour notice, much can be done, but with five minutes notice, the possibilities are few. Current early warning systems, notably NASA’s Advanced Composition Explorer (ACE), can provide between 15 minutes and one hour of warning for incoming solar storms, allowing power companies to prepare their systems and minimise damage. However, ACE is already operating beyond its planned lifespan and a very powerful solar flare would likely saturate its sensors. Building a back-up warning system would be sensible, but one huge problem is that “it is terribly difficult to inspire people to prepare for a potential crisis that has never happened before and may not happen for decades to come” [NRC, 2008: 90].
In conclusion, despite our generally good understanding of the physical processes that create solar storms and of how such extreme space weather will impact modern technologies, the systems involved are highly complex and thus a lot of uncertainty remains with regard to our ability to forecast space weather events and to analyse our future vulnerabilities. If current trends continue, it is likely that our vulnerability to solar storms will further increase. Safeguarding our technological infrastructures will require substantial investments from the public and private sectors, but it is difficult to know if, should we make the investment, it will be sufficient; or should we choose not to make the investment, how severe the societal and economic consequences will be.
Emerging Risks: Solar storms, October 2010 © International Risk Governance Council, 2010.Reproduction of original IRGC material is authorized provided that IRGC is acknowledged as the source.
SOLAR FLAIR HISTORY
The Perfect Solar Superstorm - Article from History.com
The sun brings gives light and warmth to all life on Earth, but it has a temper too. Solar flares, eruptions and other sun storms can have serious effects to satellites and other systems around or on Earth.
Take a look at some of the worst solar storms known to humanity.
The Carrington Event
On the morning of September 1, 1859, amateur astronomer Richard Carrington ascended into the private observatory attached to his country estate outside of London. After cranking open the dome’s shutter to reveal the clear blue sky, he pointed his brass telescope toward the sun and began to sketch a cluster of enormous dark spots that freckled its surface. Suddenly, Carrington spotted what he described as “two patches of intensely bright and white light” erupting from the sunspots. Five minutes later the fireballs vanished, but within hours their impact would be felt across the globe.
That night, telegraph communications around the world began to fail; there were reports of sparks showering from telegraph machines, shocking operators and setting papers ablaze. All over the planet, colorful auroras illuminated the nighttime skies, glowing so brightly that birds began to chirp and laborers started their daily chores, believing the sun had begun rising. Some thought the end of the world was at hand, but Carrington’s naked eyes had spotted the true cause for the bizarre happenings: a massive solar flare with the energy of 10 billion atomic bombs. The flare spewed electrified gas and subatomic particles toward Earth, and the resulting geomagnetic storm—dubbed the “Carrington Event”—was the largest on record to have struck the planet.
Bright Flare, Dark Lines
Compared to today’s information superhighway, the telegraph system in 1859 may have been a mere dirt road, but the “Victorian Internet” was also a critical means of transmitting news, sending private messages and engaging in commerce. Telegraph operators in the United States had observed local interruptions due to thunderstorms and northern lights before, but they never experienced a global disturbance like the one-two punch they received in the waning days of summer in 1859.
Many telegraph lines across North America were rendered inoperable on the night of August 28 as the first of two successive solar storms struck. E.W. Culgan, a telegraph manager in Pittsburgh, reported that the resulting currents flowing through the wires were so powerful that platinum contacts were in danger of melting and “streams of fire” were pouring forth from the circuits. In Washington, D.C., telegraph operator Frederick W. Royce was severely shocked as his forehead grazed a ground wire. According to a witness, an arc of fire jumped from Royce’s head to the telegraphic equipment. Some telegraph stations that used chemicals to mark sheets reported that powerful surges caused telegraph paper to combust.
On the morning of September 2, the magnetic mayhem resulting from the second storm created even more chaos for telegraph operators. When American Telegraph Company employees arrived at their Boston office at 8 a.m., they discovered it was impossible to transmit or receive dispatches. The atmosphere was so charged, however, that operators made an incredible discovery: They could unplug their batteries and still transmit messages to Portland, Maine, at 30- to 90-second intervals using only the auroral current. Messages still couldn’t be sent as seamlessly as under normal conditions, but it was a useful workaround. By 10 a.m. the magnetic disturbance abated enough that stations reconnected their batteries, but transmissions were still affected for the rest of the morning.
Sky on Fire
When telegraphs did come back on line, many were filled with vivid accounts of the celestial light show that had been witnessed the night before. Newspapers from France to Australia featured glowing descriptions of brilliant auroras that had turned night into day. One eyewitness account from a woman on Sullivan’s Island in South Carolina ran in the Charleston Mercury: “The eastern sky appeared of a blood red color. It seemed brightest exactly in the east, as though the full moon, or rather the sun, were about to rise. It extended almost to the zenith. The whole island was illuminated. The sea reflected the phenomenon, and no one could look at it without thinking of the passage in the Bible which says, ‘the sea was turned to blood.’ The shells on the beach, reflecting light, resembled coals of fire.”
The sky was so crimson that many who saw it believed that neighboring locales were on fire. Americans in the South were particularly startled by the northern lights, which migrated so close to the equator that they were seen in Cuba and Jamaica. Elsewhere, however, there appeared to be genuine confusion. In Abbeville, South Carolina, masons awoke and began to lay bricks at their job site until they realized the hour and returned to bed. In Bealeton, Virginia, larks were stirred from their sleep at 1 a.m. and began to warble. (Unfortunately for them, a conductor on the Orange & Alexandria Railroad was also awake and shot three of them dead.) In cities across America, people stood in the streets and gazed up at the heavenly pyrotechnics. In Boston, some even caught up on their reading, taking advantage of the celestial fire to peruse the local newspapers.
Ice core samples have determined that the Carrington Event was twice as big as any other solar storm in the last 500 years. What would be the impact of a similar storm today? According to a 2008 report from the National Academy of Sciences, it could cause “extensive social and economic disruptions” due to its impact on power grids, satellite communications and GPS systems.
Preparing for Solar Flairs/Electromagnetic Pulse