A conference next week will discuss the threat from electromagnetic storms from the sun, which could paralyse high-tech infrastructure. The last such storm was in 1859, and blocked telegraph communication, then in its infancy. But the low-technology systems then in use were little affected.
Electromagnetic storms are caused by solar flares but similar damage can be caused by electromagnetic pulses from nuclear explosions. Most affected will be - it is only a matter of time before this happens - extended power lines such as the electricity grid, and satellites and the systems that depend on them, including GPS. But the disruption could potentially be far more widespread, as heavy current surges in the grid would damage switchgear and transformers, and it could take years to get everything back into service.
The most vulnerable services are the pumps that keep the water supply and sewage systems running. Failure would quickly lead to flooding, contamination and outbreaks of disease. Electrical transport systems would come to a standstill, with the failure of both traction supplies and signalling.
The question that must be asked is whether we have made ourselves too dependent on high technology and what can be done to reduce our vulnerability?