The Carrington Event: When Will We Have Another?

Back in the pre-Cadence days when I had the EDAgraffiti blog, I wrote about the Carrington event. I got a lot of positive feedback about it from people in the electronics industry, mostly saying that they had never heard of it.

The Carrington Event was a solar storm in 1859 that lasted for several days. On September 1 of that year, there was a coronal mass ejection (CME) traveling directly towards the earth and causing an extended electromagnetic pulse (EMP). Normally such an event would take several days to reach earth but an earlier ejection had cleaned out all the ions in space and it took less than a day to get here. It was the biggest electrical storm in recorded history. People got up thinking it was daylight. Aurora Borealis (Northern Lights) were seen as far south as the Caribbean and Hawaii. Telegraph systems failed, in some cases shocking their operators and in other cases having enough power to continue functioning even though they were turned off.

Of course, we didn't have electronics in those days. So what would happen today?

There was a major CME predicted on December 10, just a few months ago. But it got downgraded a couple of days before:

The predicted solar storm on Earth predicted for Thursday evening has been downgraded from “strong” to “minor” by NOAA’s Space Weather Prediction Center. As such, auroras are no longer expected in the northern Lower 48 states. 

Solar flares go in an 11-year cycle, aka the sunspot cycle. Today, we are in Solar Cycle 25. The last cycle was unusual for its low number of sunspots and there are predictions that we could be in for an extended period of low activity like the Maunder minimum from 1645-1715 (the little ice age when the Thames froze every winter) or the Dalton minimum from 1790-1830 (where the world was also a couple of degrees colder than normal). But for electronics, the important thing is the effect of CME which seems to be caused by solar flares, although the connection isn't completely understood. Obviously, the most vulnerable objects are satellites since they lack the protection of the earth's magnetic field but power grids are also especially vulnerable because their long wires are perfect for concentrating the electrical pulse. There seems to be an event like this about every 150 years which means we are overdue. In other news, we're also overdue for a big earthquake in California.

In 1859, telegraph systems were down for a couple of days and people got to watch some interesting stuff in the sky. But from a NASA conference a few years ago in Washington looking at what would happen if another Carrington Event occurred:

The situation would be more serious. An avalanche of blackouts carried across continents by long-distance power lines could last for weeks to months as engineers struggle to repair damaged transformers. Planes and ships couldn’t trust GPS units for navigation. Banking and financial networks might go offline, disrupting commerce in a way unique to the Information Age. According to a 2008 report from the National Academy of Sciences, a century-class solar storm could have the economic impact of 20 Hurricane Katrinas.

Actually, it sounds worse to me. This is the result of a much smaller event:

In March of 1989, a severe solar storm induced powerful electric currents in grid wiring that fried a main power transformer in the HydroQuebec system, causing a cascading grid failure that knocked out power to six million customers for nine hours while also damaging similar transformers in New Jersey and the United Kingdom.

UN forces in Namibia were also affected. So Africa, Quebec, New Jersey, the UK. That's a pretty big geographical spread. Imagine that scaled up an order of magnitude.

Solar flares are classified as A, B, C, M, and X. based on the peak flux in watts per square meter of X-rays at the Earth, measured by NASA's Geostationary Operational Environmental Satellite Program (GOES). There are also numerical suffixes from 1 to 9, with each representing an increase of the flux. But it is done in a slightly weird way, so that A2 is twice A1, but A3 is three times A1 (not twice A2), all the way up to A9 at nine times A1, and then 10X A1 is B1. There is no limit on the numbers after X since there is no new letter. That 1989 solar storm I mentioned just above was estimated at X15, and like the Carrington Event, there had been another big CME a couple of days before that had cleared out space between the sun and the earth, making it worse.

There was (probably) an X4.4 solar flare on November 29, 2020. But luckily it was on the far side of the sun and so the earth was not threatened. But that also made it hard to measure, so the X4.4 is more of a guess.

But what if it had been pointed towards the earth? How serious might it be?

A couple of years ago, a congressional committee report stated that a large electromagnetic pulse (EMP) inundating America could cause 90% of Americans to die. The EMP is inevitable. The dead Americans are not, if we prepare.

On a TV program back then, an expert called Peter Pry gave his perspective. Pry is considered America's foremost expert on this topic. He has two PhDs, a certificate on nuclear weapon design, worked at the CIA for a decade, worked on the House Armed Services Committee, and then served as director of the EMP Committee. Pry explained that an EMP can happen in a few different ways: if an adversary attacks America using nuclear weapons, or naturally via a large solar storm. The reason why a large EMP hitting Earth is inevitable is that solar storms are inevitable. They happen regularly. The only question is when a large one will cross Earth's path. There will eventually be a second Carrington Event.

Electronics nowadays are far more sensitive and thus even more vulnerable to an EMP. The next Carrington Event will destroy electrical systems and electronics around the entire world. Refrigerators and freezers will go off. Gas pumps will stop working. Even tap water will stop flowing. Perhaps the tin-foil brigade who live in rural areas will be okay. But most Americans live in cities. Even in Californian cities, most inhabitants do not even keep a few gallons of water on hand to survive a few days after the inevitable future earthquake.

One particular worry is the fact that extra-high-voltage transformers, which our electric grid depends on, will be wrecked. The North American grid has about 2,000 of the biggest transformers. They are so huge and difficult to make that the worldwide capacity for manufacturing new ones is just 200 a year. To make things worse, America doesn't even make these transformers anymore, we import them. It would take years to replace our transformers in a best-case scenario. So Americans would be without electricity effectively indefinitely. We should definitely harden the grid with redundancy, and stockpile transformers, so that this would not happen. Estimates seem to be a few billion dollars, so a drop in the sea compared to what we have spent on COVID-19 so far (hey, and they both have "corona" in their name).

This IEEE Spectrum article from last year Here Are the U.S. Regions Most Vulnerable to Solar Storms reckons that Minnesota, Wisconsin, and North Dakota are most vulnerable. That is not because of latitude or temperature, but how conductive the underlying rock is. That was one reason Quebec was so affected in the 1989 flare — it is on old insulating rock. Here's another quote from that piece:

“There’s some expectation that if we were to have a repeat of the 1859 storm, it could have some substantial effects on the electric power grid and other technology that modern society depends upon,” Love said . "And because so many of today’s electrical systems are built around computer chips that are not robust to high-voltage surges, the fear is that a modern-day Carrington event could also blow out some portion of our computerized world.

Love in that paragraph is Jeffrey Love, a research geophysicist at the U.S. Geological Survey. He is also a co-author of the USGS study A 100‐Year Geoelectric Hazard Analysis for the U.S. High‐Voltage Power Grid on which that Spectrum article is based.

Here's a 13-minute video from 2019 (I was going to say "last year" since I keep forgetting it is 2021...or maybe I just want to pretend 2020 never existed): It takes a more optimistic view of activities that have taken place in preparation over the last couple of decades.

Solar Cycle 25 will peak (solar maximum) in July 2025 when sunspots will be the most numerous, as magnetic energy, or flux, bubbles to the sun’s surface from deeper down in the plasma body. Any sunspot can produce CMEs that can be disruptive to Earth. And "disruptive" is pretty much an understatement if it is really Carrington Two.

Have a nice day!

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