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The Threat of EMP

How likely is a debilitating electromagnetic pulse, anyway?

Nuclear EMP

Nuclear EMP (View larger version)

By Patrick J. Kiger


One of the apocalyptic nightmares envisioned by doomsday preppers is an electromagnetic pulse, commonly referred to as an EMP, which in an instant could destroy the gadgetry that civilization increasingly has come to depend upon.

While an EMP might sound like a plot premise for a Hollywood disaster thriller, a federal commission of scientific and military experts convened by Congress in 2004 warned that such an event could actually occur. In its report, the commission warned that an EMP “is one of a small number of threats that has the potential to hold our society seriously at risk and might result in defeat of our military forces.”

According to the commission, here’s how an EMP might occur. An enemy would launch a missile containing a nuclear weapon, which would explode at high altitude above the U.S. and release a burst of radiation that would interact with the Earth’s magnetic field and atmosphere—including the ionosphere, the thin upper layer filled with free electrons, which facilitates radio communications. As a result, a powerful electrical current would radiate down to the Earth and create additional currents that would course through manmade electrical circuits as well. Electrical infrastructure and electronic devices would receive severe shocks, which might disrupt, damage or even destroy them.

In doing so, an EMP would have the potential to cause a massive blackout that would affect phone systems, electric power transmission, factories the financial system, and transportation. “Depending on the specific characteristics of the attacks, unprecedented cascading failures of our major infrastructures could result,” the commission warned. “In that event, a regional or national recovery would be long and difficult and would seriously degrade the safety and overall viability of our Nation.” The commission added, ominously, that “the longer the outage, the more problematic and uncertain the recovery will be.

The idea of an EMP isn’t new. In the early 1960s, U.S. national security officials worried that a Soviet nuclear bomb detonated in space could damage or destroy U.S. intercontinental missiles. To learn more, they set up a series of high-altitude nuclear tests. In July 1962, in a test known as Starfish Prime, a missile containing a 1.4 megaton nuclear warhead was detonated at a height of 248 miles over a remote area in the Pacific Ocean The blast had an unexpected effect, disrupting radio transmission as far away as California and Australia for several hours. It also damaged and ultimately disabled at least six orbiting satellites--including Telstar I, the satellite that transmitted the first live TV broadcasts from the U.S. to Europe and back again.

The disruptive potential of EMP was noticed by the Chinese and Soviets, both of whom considered such an attack, according to the commission’s report. Nevertheless, U.S. officials didn’t bother to develop any defenses against the EMP during the Cold War, because they assumed that the threat of a retaliatory nuclear attack was sufficient. Since then, however, new menaces have emerged—rogue states such as Iran and North Korea, whose volatile leaders conceivably might launch an attack despite such consequences, as well as stateless terrorist groups such as Al Qaeda.

But even if we’re not attacked by an enemy, there’s also the possibility that a catastrophic electromagnetic pulse could occur naturally, triggered by a severe solar flare. In 1989, for example, solar weather caused the collapse of northeastern Canada’s Hydro-Quebec power grid within 90 seconds, leaving millions of people without electricity for nine hours, according to a National Research Council report. In fact, Yousef Butt, a scientist at Center for Astrophysics at Harvard University, wrote in a 2010 article in the online journal Space Review that the risk of EMP from a solar storm is greater than that from an intentional attack.

But while some, such as former U.S. House Speaker and Presidential candidate Newt Gingrich, have sounded alarms about the risk of a catastrophic EMP launched by terrorists or a rogue regime, some skeptics downplay such a threat, saying that it would be difficult to pull off. Additionally, for decades the Pentagon has been hardening its electronics against an EMP threat, though state and local governments and private sector may not have been as diligent. The New York Times reported in 1983 that military computers and communication centers were protected with shields known as Faraday cages, which would absorb EMP energy and prevent it from knocking out equipment.

Others doubt that the effects of an EMP attack would be as severe as doomsayers have predicted. In a 2003 paper, Electric Power Research Institute staffer Mario Rabinowitz concluded that an EMP generated by a nuclear blast would be no more harmful to the electrical grid that natural events such as lightning storms, and notes that in the 1962 Starfish Prime test, the telecommunications system and power grid in Hawaii was not seriously damaged. A 2008 report by the Congressional Research Service, however, noted that even a less-than-devastating EMP attack could still cause a lot of damage. According to the report, an attack on the Washington DC-Baltimore region that only damaged 10 percent of communications systems and the electrical grid and 20 percent of electronic devices could still require a month of recovery time and inflict as much as $34 billion in economic losses.

Matt Dickinson
Matt Dickinson

So we should protect against it. Hopefully we can start working on that sometime. Should we ask our senators and congressmen to get on the move? Private companies should protect against it too. Even if electricity only goes out for 9 hours it can still mean people dying in hospitals. 

Theodore Simon Malya
Theodore Simon Malya

I can't envisage the consequence of this catastrophy. Just hearing the nuclear weapon makes me crumble why human being can be so creative and yet can also be very destructive? It total madness.

Grid Fixer
Grid Fixer

Thanks for the fine article, NatGeo.  It's amazing but not surprising that our friends in the federal government have known of this issue for ten years or more, yet routinely choose the politically expedient option to do nothing, leaving the nation at risk, of the highest order.  

Mr. Rabinowitz's conclusions are recognized as naive by most experts.  He apparently chooses to ignore the fact that the Starfish prime detonation was at a low latitude, known for reduced collateral effectiveness.  He also omits the fact that the technology residing in Hawaii was well over 500 miles away, and was also, by today’s standard, very, very robust, given that it was constructed using components that are gigantic compared to today’s micro circuitry, and include little-to-no computer technology.  It's unfortunate that some choose to publish his work.  

It’s my belief that this issue will only be addressed through a grass roots effort by the American public that focuses on that portion of the grid that serves one’s own community. 

Thanks again for working to keep EMP and CME in the public lexicon. 


Andy Nguyen
Andy Nguyen

another pointless show to exploit.

shame on you, nat geo.