Off the grid What would the world do if the internet just collapsed?

After a glitch at a datacentre caused a minor meltdown last month, internet experts reveal the scenarios that could leave us disconnected

- Aisha Down

It is the morning after the internet went offline and you are likely to be wondering what to do.

You could buy groceries with a chequebook, if you have one. Call into work with the landline - if yours is still connected. After that, you could drive to the shop, as long as you don't need to use 5G to navigate.

A datacentre glitch in the US state of Virginia recently reminded us that this is not impossible. The internet may have become a linchpin of modern life, but it is also a web of creaking legacy programs and physical infrastructure, leading some to wonder what it would take to bring it all down.

The answer could be as simple as some acute bad luck, a few targeted attacks, or both. Extreme weather takes out a few key datacentres. A line of AI-written code deep in a major provider - such as Amazon, Google or Microsoft - is triggered unexpectedly and causes a cascading software crash. An armed group or intelligence agency snips a couple of undersea cables.

These would be bad. But the real doomsday event, the kind that the world's few internet experts still worry about in private Slack groups, is slightly differenta sudden, snowballing error in the creaky, decades-old protocols that underlie the whole internet. Think of the plumbing that directs the flow of connection, or the address books that allow one machine to locate another.

It could start when a tornado cruises through the town of Council Bluffs, Iowa, laying waste to a low-slung cluster of datacentres that are an integral part of Google's offering. This area, called us-central1, is critical to its Cloud Platform as well as YouTube and Gmail - a 2019 outage here downed these services across the US and Europe.