Zapping Charlemagne's Power Grid: A Solar Superflare in AD 774?

Radiocarbon data indicate a jump in 14C synthesis in AD 774-775. I show that, contrary to the original publication, this is consistent with a solar superflare close to current upper limits. It is also typical for the lower end of flare energies observed on solar-type stars. Such a solar proton event would cause moderate ozone depletion, but not a mass extinction event. About 20 times more powerful than the famous 1859 Carrington Event, it would be disastrous for modern electromagnetic technology. I discuss the probability of such an event in the near future.