Geomagnetic storms: history's surprising, if tentative, reassurance

Abstract

My last post raised the specter of a geomagnetic storm so strong it would black out electric power across continent-scale regions for months or years, triggering an economic and humanitarian disaster. How likely is that? One relevant source of knowledge is the historical record of geomagnetic disturbances, which is what this post considers. In approaching the geomagnetic storm issue, I had read some alarming statements to the effect that global society is overdue for the geomagnetic “Big One.” So I was surprised to find reassurance in the past. In my view, the most worrying extrapolations from the historical record do not properly represent it.