6. Grid electricity is a key vulnerability.
“When the power goes down, everything stops. This is not to say that grid power is essential to all human life: far from it (a handy book on my shelf is titled Living Without Electricity). But as things are, we’re set up to depend on electricity for computers, smart phones, refrigerators, gasoline pumps, water pumps, cash registers, credit card machines, and more. The grid is a brittle system that can go down remarkably easily.”