North Korean EMP Attack ‘Existential Threat’ to US, Experts Warn

With this year’s revelation that North Korea’s nuke-tipped missiles could likely reach the West Coast of United States, a more insidious threat has gained prominence—an electromagnetic pulse (EMP) attack.

While not deadly on its own, an EMP attack can ruin most electronics within a massive radius and could cripple the power grid, sending the country back into the 18th century—potentially a death sentence for a large part of the population.

Worse yet, such a catastrophic scenario could be triggered by a lone, relatively weak nuclear weapon, just like those wielded by North Korea, experts have warned.

“It is critical … that the U.S. national leadership address the EMP threat as a critical and existential issue,” stated leading experts on the freshly defunded congressional EMP Commission in an Oct. 12 testimony to a House subcommittee hearing on the North Korean threat to the United States.

The commission was set up by Congress in 2001 to figure out how much damage an EMP attack could cause and how to protect against it. It was defunded on Sept. 30 and is to be replaced.

The commission has produced two reports, one in 2004 and another in 2008, painting a gloomy picture of a mostly unprepared nation so vulnerable it “invites attack.”

How Does EMP Work?

The capability of a nuclear explosion to produce an EMP was a surprise to scientists of the early 1960s. It was discovered when the United States and the Soviet Union conducted a series of high-altitude nuclear tests.

Here is how it works:

  • A nuclear explosion produces gamma rays.
  • The gamma rays strip electrons from atoms in the atmosphere.
  • As the electrons fly away from the explosion toward the surface, they get trapped in the Earth’s magnetic field.
  • They start to spiral along the magnetic field lines, generating an electromagnetic pulse.
  • Because the electrons travel at near-light speed, trillions of trillions of them produce the pulse at virtually the same time, creating a single burst of electromagnetic energy.
  • The pulse travels toward the surface and is picked up by all electrical conductors.
  • Wires in electrical circuits pick it up, just like antennae pick up radio waves, and it manifests as a brief spike in voltage.
  • The longer the wire, the more of the pulse it picks up and the higher the voltage spike.
  • Because modern electronic parts usually operate on only a few volts, even a small spike can damage them.
  • Because a nuke-induced EMP produces tens of thousands of volts per meter and because most electronics are connected to a power supply by a cable at least a meter long, the burst could easily fry them.

But it doesn’t end there.

A high-altitude nuclear explosion creates a disturbance in the Earth’s magnetic field. Just as electricity is induced in a loop of wire if we move a magnet around it, electric currents also get induced in all electrical circuits with the sudden shift of the planet’s magnetic field. They are called geomagnetically induced currents (GIC). They build up gradually and can last tens of seconds. And again, the longer the wire, the stronger the current. Long power transmission lines are thus especially vulnerable and the GIC disruption can destroy transformers attached to them.

This is actually the main problem. There are some 2,000 extra high voltage (EHV) transformers across the country. If enough of them are damaged, virtually the whole grid shuts down.

And replacing them would take years. The transformers are custom made in Germany and South Korea and it takes 18 months to make one, according to Peter Vincent Pry, former EMP Commission chief of staff.

“With few exceptions, the U.S. national electric grid is unhardened and untested against nuclear EMP attack,” the commission’s testimony states. “In the event of a nuclear EMP attack on the United States, a widespread protracted blackout is inevitable.”

Most people are not ready for a blackout longer than a few days—not to mention years. Tap water runs thanks to pumps—connected to the power grid; food arrives to stores in trucks that run on diesel pumped by gas stations—connected to the power grid.

Author and historian William Forstchen attempted to imagine a post-EMP America in his 2009 novel “One Second After.” The novel ended one year after an attack with 90 percent of the population dead.

“We think that is in the correct range,” EMP Commission Chair William Graham told House Armed Services Committee in 2008.

Can North Korea Do This?

Experts believe North Korea likely has 10-20 kiloton warheads small enough to fit in its missiles that are capable of reaching the West Coast.

A 10-kiloton warhead detonated around 45 miles above the earth’s surface could potentially cause EMP damage with a radius of over 570 miles, according to Graham.

A 10-kiloton EMP could destroy dozens of EHV transformers and thousands of control elements, “causing catastrophic collapse and protracted blackout of the U.S. Eastern Grid, putting at risk the lives of millions,” the EMP Commission estimated.

However, the commission likely expected the nuke to explode above the middle of the country, not above the West Coast. Most of the power grid infrastructure is concentrated in the eastern half of the country.

But North Korea could also hide the nuke in a satellite and put it in the orbit above the United States. North Korea already has two satellites crossing over America, Graham pointed out.

Worse yet, in 2004, two Russian generals and EMP experts warned the EMP Commission that the design for Russia’s super-EMP warhead was “accidentally” transferred to North Korea. They said the warhead can generate an EMP of 200,000 volts per meter—four times what was previously expected from an EMP attack.

Can We Shield the Transformers?

It would take $1 billion-$5 billion to harden the grid against a GIC event, said John Houston, chairman of the Electric Power Research Institute’s Power, Delivery and Utilization Council. That was back in 2011.

Last year, the Electric Power Research Institute launched a research project into EMP effects on the power grid. “The three-year project is about half complete but results are released as completed through the project schedule,” said Rob Manning, the institute’s vice president of Transmission and Distribution.

So far, however, utility companies seem hesitant to make the investment.

“Because the effects of an EMP attack on the energy grid are not sufficiently understood or remain classified, crafting appropriate mitigations and making business-risk decisions to address EMP threats require more research,” stated an August policy brief of the Edison Electric Institute (EEI), an industry association that represents all U.S. investor-owned electric companies that provide electricity for about 220 million Americans.

Dozens of utility companies have an agreement to share transformers in case of an attack, which is a good start, Houston said.

But as long as the overall vulnerability to an EMP continues, it gives a certain strategic advantage to North Korea.

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