The effects of an electromagnetic pulse (EMP) attack in the form of high-altitude nuclear weapons and geomagnetic disturbances (GMD) from coronal mass ejections have been studies by government and private organizations. The similar consequences of both can be devastating. As much as 90 percent of the U.S. population may not survive a “grid-down” environment lasting a year or more — and the National Academy of Sciences projected a 4 to 10 year recovery period for a “severe” event affecting a large regional expanse.