Comment NASA agrees (Score 5, Informative) 182
I'm going to temper that apocalyptic-looking premise with a quote from that NASA article which may provide a little... comfort.
The worst geomagnetic storm of the Space Age, which knocked out power across Quebec in March 1989, registered Dst=-600 nT. Modern estimates of Dst for the Carrington Event itself range from -800 nT to a staggering -1750 nT.
So, that's 'only' up to 3x as bad as an event that happened in 1989, and we seemed to have got through that okay (their power was cut for 11 hours apparently).
Maybe even NASA is over-reacting a bit on this then..... But like CO2 emissions, it's best not to take the chance. It is possible to protect the grid to a large extent if the world cared enough the risk. I think we're talking in the range of $billions of investment to save $trillions of damage when the inevitable happens (definitely a question of when, rather than if).