There has been a great deal of concern over North Korea’s nuclear weapons program as of late, with PDRK dictator Kim Jong-Un threatening, on numerous occasions, to launch a nuclear attack against the United States. These concerns have focused primarily on the possibility of a direct nuclear strike, but experts speaking at a House of Representatives hearing held on October 12 pointed out that, while a limited nuclear exchange with direct strikes would cause terrible destruction, North Korea could conceivably wipe out 90 percent of the population of U.S. within a year with the deployment of a single device: the detonation of a high-altitude EMP bomb.
According to the statement made by the Commission to Assess the Threat to the United States from Electromagnetic Pulse (EMP) Attack, the "North Korean nuclear tests, including the first in 2006… mostly have yields consistent with the size of a Super-EMP weapon." Such a Super-EMP weapon would be "low-yield and designed to produce not a big kinetic explosion, but rather a high level of gamma rays." This intense burst of gamma radiation can induce high-voltage electrical spikes in electronic circuits, spikes that can not only disrupt, but also destroy the affected electronics. If the Super-EMP device is detonated high above the atmosphere, the gamma burst from the explosion interacts with the Earth’s magnetic field, spreading the EMP effect over a continent-spanning area.
"While most analysts are fixated on when in the future North Korea will develop highly reliable intercontinental missiles, guidance systems, and reentry vehicles capable of striking a U.S. city, the threat here and now from EMP is largely ignored," the Commission warns. "EMP attack does not require an accurate guidance system because the area of effect, having a radius of hundreds or thousands of kilometers, is so large. No reentry vehicle is needed because the warhead is detonated at high-altitude, above the atmosphere. Missile reliability matters little because only one missile has to work to make an EMP attack against an entire nation."
The Commission also warns that North Korea wouldn’t even require a long-range rocket to put a super-EMP device over its intended target, but could loft "a warhead to 30 kilometers burst height by balloon. While such lower-altitude EMP attacks would not cover the whole U.S. mainland, as would an attack at higher-altitude (300 kilometers), even a balloon-lofted warhead detonated at 30 kilometers altitude could blackout the Eastern Electric Power Grid that supports most of the population and generates 75 percent of U.S. electricity."
While a direct nuclear strike would cause hundreds of thousands to millions of immediate casualties, depending on the scope of the attack, a single EMP could conceivably cripple enough of the country’s life-sustaining infrastructure to inflict a massive death-toll over time: without the internet, cellphones and computers, communication and commerce would be impossible; food supply routes would be cut as trucks and other vehicles that rely on electronics would be rendered useless; and hospitals would see their abilities to administer to their patients severely crippled.
In regards to the potential number of casualties that the detonation of a high-altitude EMP device would produce, the Commission quotes Ambassador Henry F. (Hank) Cooper, former Director of the U.S. Strategic Defense Initiative and an expert on missile defenses and space weapons, who warns that "the result could be to shut down the U.S. electric power grid for an indefinite period, leading to the death within a year of up to 90 percent of all Americans—as the EMP Commission testified over eight years ago."
Whether from a man-made bomb or a natural source like the Sun, the effects of an electromagnetic bombardment on our civilization’s infrastructure would be virtually identical, as outlined in Whitley’s 2012 ebook, Solar Flares: What You Need to Know.