High-altitude detonation of a nuclear warhead would wreck havoc on communications and other infrastructure.
In the early 1960s, engineers in nuclear weapons testing programs in the United States and the Soviet Union noticed an unexpected phenomenon when warheads were exploded high above the Earth's surface. The electromagnetic fields produced by the detonations often resulted in damage to electrical systems on the ground. One test 400 kilometers above Johnston Island in the South Pacific destroyed a commercial telecommunications system in the Hawaiian Islands 1,400 kilometers away.
Comment on this article in The Forum.Now, a new report by the Commission to Assess the Threat to the United States from Electromagnetic Pulse (EMP) Attack warns that a nuclear attack aimed at crippling the nation's technological backbone could be greater today than it was during the Cold War. Such an attack also would be easier to orchestrate, and potentially more devastating, than a direct hit to a major metropolitan area.
"The electromagnetic pulse generated by a high-altitude nuclear explosion is one of a small number of threats that can hold our society at risk of catastrophic consequences," the commission found.
To thoroughly understand the threat, the commission sponsored analytic tests to examine the specific vulnerabilities of critical infrastructure, including: electric power systems; telecommunications; banking and finance; petroleum and natural gas pipelines; transportation systems; food and water infrastructure; emergency services, space systems; government operations; and communications for keeping the citizenry informed. As a result, the 208-page report details the daunting complexity of modern life.
"The separation of these infrastructures into different domains tends to obscure the real interdependencies that sustain the effectiveness and daily operation of each one," the report found. To illustrate the point, the commission noted that the accidental severing of a single fiber-optic cable in New York City in 1991 resulted in a power failure that blocked 60 percent of phone calls into and out of the city, disabled air traffic control functions in the Washington-Boston flight corridor (the busiest in the nation) and crippled the operations of the New York Mercantile Exchange.
"The increasingly pervasive use of electronics of all forms represents the greatest source of vulnerability to attack by EMP. Electronics are used to control, communicate, compute, store, manage and implement nearly every aspect of U.S. civilian systems," the commission reported.
"Should significant parts of the electric power infrastructure be lost for any substantial period of time, the commission believes that the consequences are likely to be catastrophic, and many people may ultimately die for lack of the basic elements necessary to sustain life in dense urban and suburban communities," the report noted. Such is possible, the commission said, because some critical electrical system components are no longer manufactured in the United States, and acquiring them in routine circumstances can take a year.
In July, the House Armed Services Committee received a preview of the report's findings in testimony by William R. Graham, chairman of the commission. "Our vulnerability is increasing daily as our use of and dependence on electronics continues to grow in both our civil and military sectors," Graham said.
"What is significant about an EMP attack is that one or a few high-altitude nuclear detonations can produce EMP effects that can potentially disrupt or damage electronic systems over much of the United States, virtually simultaneously, at a time determined by an adversary," Failure to address the vulnerability could both invite and reward an attack.
Graham noted that an adversary wouldn't have to have long-range ballistic missile capability to deliver an EMP attack. Such an attack could be launched from a freighter off the coast of the United States, using a short- or medium-range missile loaded with a nuclear warhead.
"Iran, the world's leading sponsor of international terrorism, has practiced launching a mobile ballistic missile from a vessel in the Caspian Sea," Graham said. "Iranian military writings explicitly discuss an EMP attack that would gravely harm the United States. While the commission does not know the intention of Iran in conducting these activities, we are disturbed by the capability that emerges when we connect the dots."
The commission found that large-scale, long-term consequences of an EMP attack could be reduced below the level of catastrophe through a coordinated effort by the government and private sector. In November, the commission will report on the progress of protecting the nation from an EMP attack.