On 1 September 1859, a British astronomer named Richard Carrington was sketching sunspots when he witnessed two brilliant white flares erupt from the sun's surface. Seventeen hours later, the sky over the Caribbean glowed bright enough to read a newspaper at midnight. Telegraph operators in Boston unplugged their machines and kept sending messages using only the current induced by the storm itself. Some telegraph pylons threw sparks. Some operators got electric shocks. A few telegraph offices caught fire.
This was the Carrington Event. The most powerful geomagnetic storm in recorded history. It was spectacular, mildly inconvenient, and largely harmless.
Because in 1859, the most complex piece of electronics on the planet was a telegraph wire.
The modern version
A Carrington-scale event today would be a different story. Not spectacular. Catastrophic.
The sun ejects a coronal mass ejection, a billion-tonne cloud of magnetised plasma, aimed squarely at Earth. We'd get about 15 to 30 hours of warning from solar observation satellites, assuming the storm didn't knock those out first. Then the geomagnetic field distorts, and massive currents flow through any long conductor on the planet. Power lines. Telephone cables. Pipelines. Railway tracks.
Transformers in the electrical grid absorb these induced currents and overheat. Not gently. Violently. The copper windings in high-voltage transformers melt. And here's the part nobody talks about enough: those transformers aren't off-the-shelf components. Each one is custom-built, weighs between 100 and 400 tonnes, costs upwards of £5 million, and takes 12 to 18 months to manufacture. There are roughly 2,000 of these in the UK grid alone.
If a significant fraction of them fail simultaneously, you can't just order replacements. The factories that build them also need electricity.
What goes dark
Everything plugged into the wall, obviously. Lights, refrigerators, ovens, heating systems, air conditioning. But that's just the start.
Water treatment plants run on electricity. Within 24 hours of the grid failing, water stops flowing from your tap. Not because the reservoirs are empty, but because the pumps that move water through the system have no power. Sewage treatment fails at the same time. In summer, this becomes a public health crisis within days.
Petrol stations can't pump fuel. Their underground tanks are full, but the pumps are electric. Every car with fuel in the tank still works, but once that tank runs dry, you're walking. Diesel generators kick in at hospitals and military installations, but diesel supply chains depend on electric pumps too. There's a clock ticking on every backup system.
The internet ceases to exist. Not metaphorically. The data centres that store every website, email account, and streaming service you've ever used run on grid power with battery and generator backup measured in hours, not weeks. Your photos, your documents, your messages. Gone. Not deleted, exactly. Just inaccessible on servers sitting in dark rooms drawing no power.
The phone in your pocket
Your mobile phone itself probably survives the storm. Consumer electronics with short wiring aren't great antennas for geomagnetically induced currents. Your phone might be fine. It just can't connect to anything, because every mobile tower, every fibre-optic junction, every undersea cable repeater has lost power or been fried.
You're holding a small glass rectangle that can play about six hours of downloaded music, display some cached photos, and tell you the time until the battery dies. That's it. That's what your £1,000 smartphone is without infrastructure.
A torch with a clock.
Food
The UK imports roughly 46% of its food. Almost all of it arrives by ship, is unloaded by electric cranes, transported by lorries using electrically-pumped diesel, stored in electrically-refrigerated warehouses, and sold in shops with electric tills and electric doors. Cut the power and this entire chain stops.
Supermarkets carry roughly three days of stock at any given time. That's not a guess. It's a widely cited industry figure from the UK government's own food security assessments. Within 72 hours of a total grid failure, shelves are empty.
Farming continues. Crops don't need electricity to grow. But harvesting, processing, and distributing food at industrial scale absolutely does. The country reverts to localised food systems within weeks. If you live near farms, you eat. If you live in a dense urban area with no agricultural land for miles, you have a serious problem.
Money
Every bank balance, every share portfolio, every pension fund, every mortgage record exists as data on servers. Physical cash still works, and whoever has it is wealthy. But the UK's total physical currency in circulation is about £80 billion. The total value of UK bank deposits is over £8 trillion. Ninety-nine per cent of the country's money is fictional until the servers come back.
Barter economies emerge within weeks. A plumber who can fix a hand pump is worth more than a hedge fund manager. An electrician is literally the most valuable person in any community, because they're the ones who might be able to get a generator running.
How long until recovery
A 2013 report by Lloyd's of London estimated that a Carrington-scale event could leave 20 to 40 million people in the US without power for one to two years. The UK, with a smaller and older grid, would likely fare worse. The National Grid's own assessments suggest that cascading transformer failures could take three to five years to fully repair, because manufacturing capacity is global and every country would be competing for the same limited production slots.
Three to five years without reliable electricity. No heating in winter. No refrigeration in summer. No communication beyond what you can shout or write on paper and carry by hand.
It's not the end of civilisation. Civilisation existed for millennia without electricity. But the transition from a society built entirely around electrical infrastructure to one functioning without it would be violent, chaotic, and measured in deaths per day for the first several months. We don't have the manual skills, the local supply chains, or the social structures that pre-electric societies developed over centuries. We'd be building them from scratch while also trying to keep seven billion people fed.
The probability
NASA estimates the probability of a Carrington-scale event hitting Earth in any given decade at roughly 12%. In July 2012, a coronal mass ejection of similar magnitude to the Carrington Event missed Earth by approximately nine days of orbital position. Had it occurred one week earlier, it would have hit us directly.
We got lucky. We won't always get lucky. And the transformer manufacturers aren't building any faster.