this post was submitted on 22 Nov 2024
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[–] ricecake@sh.itjust.works 5 points 1 month ago

https://apps.dtic.mil/sti/pdfs/ADA484497.pdf

Tldr it's still definitely bad, but it's not the irreversible one-shot to a continent and the climate that it was made out to be.
Electrical and communications systems are built to tolerate natural phenomenon that have marked similarities to EMP, so while the EMP would definitely knock out power in the most impacted areas and to a great extent in more outlying areas, major components would be able to be brought back online in a timely fashion, and backup systems would remain available for key portions of infrastructure, such as battery and diesel generators to keep emergency communication systems online.

Communication infrastructure is particularly sensitive to EMP, but as a result it's been insulated due to practical necessity against environmental sources, as well as as a deliberate defense against EMP, since we've known about the risks for decades.

EMP does damage proportional to the size of the conductor it's attached to, since it causes current to flow, and the more there is, the more current flows. That's why power lines generate massive currents, and small things don't.
A cell phone has a very small antenna, so while it's fragile it's not getting hit as hard and can potentially just be disrupted but not physically damaged.
Computers are sensitive to single digit voltage fluctuations, but their parts aren't big enough to generate enough current to burn anything, and the source of the biggest current, the power grid, is already insulated from the sensitive parts because the grid regularly has fluctuations that could cause disruptions, and can be reasonably predicted to have potentially damaging fluctuations often enough to warrant components that burn out in a controlled fashion to protect expensive things.

Damage would be severe, widespread, and variously protracted. Not a quick trip back to the 1800s though. More like the great blackout of 2003, but with a bit more fire.