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Extreme solar storms hit Earth in 774 and 993AD — What would happen if one hit now?

Solar Storm, geomagnetic storm, 2012

August 31, 201. This coronal mass ejection just missed Earth, according to NASA

There were two mysterious sudden spikes in carbon 14 in tree rings around a thousand years ago. Now some researchers at Lund University say they’ve matched those to beryllium layers in ice cores from the Arctic and Antarctic. Some wild event made these changes across continents all over the world at the same time, and about the only thing that could  have done that was a massive solar storm (or two). There are estimates these extreme storms would have been ten times stronger than the biggest solar storms we have had in the last few decades. The two big bad storms are described as a few times bigger than even the largest solar storm in modern history, which was The Carrington Event in 1859. The radioactive spikes specifically show up in tree rings in 774/775AD and 993/994AD. It’s pretty cool that we can pin those years down so accurately, and as an aside, I imagine it makes a fairly handy calibration point for tree ring researchers now that we know it was global.

Unfortunately, if one of those happened now, it would not be fun. The stream of particles off such a major storm would play havoc with our electrical networks and equipment. We’d get only hours (or less) of warning, but the power blackouts that follow could last for months. Transformers, apparently, are particularly vulnerable to being destroyed  — and  the waiting list for new ones is five months.The Lloyds insurance report makes for rather ominous reading, and it was only describing the possibility of another Carrington event, not one these bigger solar-bombs.

The Carrington event in 1859 turned the sky blood red in places and produced auroras as far south as Panama (18 degrees North of the equator). Many telegraph systems stopped working, but in others operators even turned off their batteries just to run on “auroral current”.

If one of those geomagnetic superstorms was launched at us, and was widespread, it’s hard to imagine how it would not get really ugly. Ponder the anarchy of trying to operate cities of millions without electricity, without running water, with fuel pumps inoperable, and no fridges and freezers to store food. (A good movie script if ever there was…). The level of disaster would depend on whether there were many unscathed western regions that could help out.

NEWS: Traces of enormous solar storms in the ice of Greenland and Antarctica

“Solar storms and the particles they release result in spectacular phenomena such as auroras, but they can also pose a serious risk to our society. In extreme cases they have caused major power outages, and they could also lead to breakdowns of satellites and communication systems. According to a new study solar storms could be much more powerful than previously assumed. Researchers have now confirmed that Earth was hit by two extreme solar storms more than 1000 years ago.

“If such enormous solar storms would hit Earth today, they could have devastating effects on our power supply, satellites and communication systems,” says Raimund Muscheler at the Department of Geology, Lund University.

Stronger than the Carrington Event

“The new analysis of these past solar storms also confirms that they were several times stronger than the most intense solar storms that have been recorded on Earth. The largest solar flare ever measured came in 1859, during the so-called Carrington Event. Named for British astronomer Richard Christopher Carrington who discovered and tracked the solar outburst, the event disrupted telegraph service around the world.     —  Eric Berger, Ars Technica

Lloyds insurance writes on the risks of geomagnetic storms to the North American grid:

As the North American electric infrastructure ages and we become more and more dependent on electricity, the risk of a catastrophic outage increases with each peak of the solar cycle. Our society is becoming increasingly dependent on electricity. Because of the potential for long-term, widespread power outage, the hazard posed by geomagnetic storms is one of the most significant.

Weighted by population, the highest risk of storm-induced power outages in the US is along the Atlantic corridor between Washington D.C. and New York City. This takes into account risk factors such as magnetic latitude, distance to the coast, ground conductivity and transmission grid properties. Other high-risk regions are the Midwest states, such as Michigan and Wisconsin, and regions along the Gulf Coast.

The total U.S. population at risk of extended power outage from a Carrington-level storm is between 20-40 million, with durations of 16 days to 1-2 years. The duration of outages will depend largely on the availability of spare replacement transformers. If new transformers need to be ordered, the lead-time is likely to be a minimum of five months. The total economic cost for such a scenario is estimated at $0.6-2.6 trillion USD…

The big question is how often do these things happen?

The Lloyds insurance report suggests a Carrington like event occurs roughly every 150 years. No one knows how often the Really Big Storms happen.

Between 371 and 17 B.C., there were seven “aurora-like torch” sightings over Greece, Italy, and southern Gaul. Seven events over ~350 years suggest that the lower limit for the recurrence interval of Quebec-level and greater storms is ~50 years. During the period 1137-1648 A.D. there were two intense geomagnetic storms in East Asia, indicating a lower limit on the recurrence interval of Carrington-scale storms of approximately 250 years. Over the period 817 AD to 1570 AD, there were 20 credible aurora sightings from Yemen, Iraq, Egypt, Syria, and Morocco, five of which were Carrington-level. This sets a lower limit on the recurrence interval of Quebec-level or greater at 38 years, and Carrington-scale events at 151 years.
Based on information from historical auroral records, the mid-point estimate for the return period of a Carrington-level is 150 years, with a reasonable range of 100 – 250 years. For a Quebec-level event, the return period is 50 years, with a reasonable range of 35 – 70 years. These estimates are consistent with return periods derived from power-law modeling of the Dst distribution26 and statistical analysis of historical events.

What can we do?

“In 2013, a major report by the Royal Academy of Engineering, warned we will only have 30 minutes to prepare for a solar ‘superstorm’ which could knock out major communications.  — http://www.dailymail.co.uk

Satellites are watching, but they are mostly old and out of date:

Currently, four space satellites (SOHO – Solar and Heliospheric Observatory, ACE – Advanced Composition Explorer, and STEREO A/B – Solar Terrestrial Relations Observatory) monitor the Sun. Situated between the Sun and Earth or along Earth’s orbit, these satellites can provide warnings of incoming CMEs on a timescale of a few days to hours. These warnings allow electric grid operators to take protective measures (i.e., decrease the electric load in the grid and increase reactive power production) before the storm hits. However these satellites are all several years past their planned mission lives43 and only one has a replacement scheduled to launch in 2014.

Additionally, several steps can be taken to harden the electric grid against geomagnetically induced currents: neutral-current-blocking capacitors can be installed to block GIC from flowing into at-risk transformers, series-line capacitors can be installed on autotransformers, improvements can be made to the tripping techniques to avoid false tripping from GIC harmonics, and the utilisation of GIC monitors at transformers will ensure that current levels remain stable.

For once a big-government response that seems sensible:

Since the 1989 Quebec storm and power outage, the Canadian government has invested $1.2 billion (about $34 per person) into protecting the Hydro-Quebec grid infrastructure, installing numerous blocking capacitors.

If only we understood the solar dynamo well enough to predict these (if that’s possible). Hopefully the next big one is a long way off.


UPDATE — Further reading

Chiefio on the threat of natural or hostile EMP bursts. How vulnerable is the USA?

“So that is the “worst possible scenario”, IMHO. A few nukes on orbit that we can’t finger, and then a staccato of EMPS as they pass overhead. No launch in the last year or two pre-event to point at. Maybe a year back some vague smudge on a long put away image of what someone thought might have been an object near one of ‘their’ satellites, but again not actionable. What do you do then?

With that pattern, you have near 100% destruction of the power grid and most everything plugged into it. Even small devices are mostly fried. Some folks, like me, taking stuff out of deep storage can have some lights on, and a radio to listen to??? Who? Radio Moscow? The BBC? Telling us we’re now a 1700s rural agrarian society again? …”  h/t John F. Hultquist

Norman Rogers: Climate Change and the Real Threat, EMPs. A 19 minute podcast.

“Rogers discusses how the federal government is wasting scarce resources on the non-existent dangers from climate change while ignoring the very real dangers to our electrical grid, banking and delivery systems from either natural or a terrorist cause electro magnetic pulse. Rogers tells us what an EMP is, why it endangers our society and economy, and what the government should be doing to prevent damage from one.”  h/t  DMA



Nature Communications, 2015. DOI: 10.1038/ncomms9611 (About DOIs).

Lloyds, 2013, “Solar storm Risk to the north American electric grid”. [PDF]


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