How serious is the threat of an "EMP Pearl Harbor"?

the United States, it could send out an electromagnetic pulse (EMP) destroying the electric grid and electrical systems across a wide swath of U.S. territory,” wrote former CIA Director R. James Woolsey and Rebeccah Heinrichs of the Foundation for the Defense of Democracies a few weeks ago in the Wall Street Journal.

Other scientists and journalists, however, have expressed strong skepticism to the threat of an EMP attack carried out by terrorists or rogue states. “The vulnerability of some of our infrastructure to nuclear EMP is real; however, the threat is overblown,” argued Yousaf Butt, a staff scientist at the Center for Astrophysics at Harvard University, in a two-part series for the Space Review early this year. (see references below to his 2-part article, and to a rebuttal from two staff members of the EMP Commission.)

Frankel believes DHS has the expertise in-house to tackle EMP preparedness but needs a Senate-confirmed leader to lead the charge. Already DHS has taken action against a nuclear terrorist attack scenarios but continues to ignore the threat of an EMP attack, he said, even though the commission provided the department with 75 unclassified recommendations to mitigate vulnerabilities and promote resiliency in U.S. critical infrastructures.

“It seems odd to us that a component of the nuclear problem is simply being ignored,” Frankel said. “The EMP mode of attack doesn’t require the smuggling in with all the dangers that is required. It doesn’t require very accurate aim, you just need to toss the thing up there more or less.”

In response to Frankel’s testimony, Senator Jon Kyl (R-Arizona) challenged the White House’s WMD preparedness efforts, stating “the depth of that commitment is highly questionable because there doesn’t seem to be the commander’s intent flowing down in sufficient robustness that everyone else gets the message.”

“Protection of the nation’s critical infrastructures from an EMP threat is both feasible and well within the nation’s means and resources to accomplish,” Frankel said.

Harwood quotes Col. Randal Larsen, executive director of the Commission on the Prevention of Weapons of Mass Destruction Proliferation and Terrorism to say that the most probable EMP event will not come from either terrorists or rogue states, but from the sun. Magnetic storms on the sun and the solar flares they generate episodically threaten astronauts and satellites, but in severe cases can affect electrical infrastructure on earth. An 1859 event shorted out telegraph wires and generated auroras seen as far south as Havana, according to NASA. “The most likely EMP threat to America is from that thermo-nuclear weapon out there at 93 million miles,” Larsen said, “we know that’s going to happen.”

Regardless of whether an high-altitude nuke attack is probable, Larsen noted, preparing the nation to withstand an EMP event will protect the country from either a man-made or a solar event.

— Read more in Yousaf M. Butt, “The EMP threat: fact, fiction, and response (part 1),” Space Review (25 January 2010); and Butt, “The EMP threat: fact, fiction, and response (part 2),” Space Review (1 February 2010); and William Radasky and Peter Vincent Pry, “Rebuttal to ‘The EMP threat: fact, fiction, and response’,” Space Review (6 July 2010)