America's Vulnerability to a Different Nuclear Threat: An Electromagnetic Pulse

[link to www.heritage.org]

In the 1980s, Americans feared neutron bombs that could kill everyone but leave buildings, roads, and cars intact. Today, Americans should fear a different kind of nuclear threat that can instantaneously destroy power grids, electronic systems, and communications along an entire coast but spare people.

This destruction would result from the split-second release of a high-energy electromagnetic pulse (EMP) after a nuclear bomb is detonated miles above the Earth and outside the atmosphere. Within a week of the blast, although no one would be instantly killed, the disruption of food and water supplies and health care caused by the shutdown of transportation, computers, networks, electronic equipment, and communication systems would have serious consequences for millions of people. 2 Recovering from such an attack could take years.

The U.S. military first witnessed this phenomenon after a series of high-altitude nuclear tests in the Johnston Atoll in 1962 generated a disruption in electronic equipment in Hawaii, nearly 1,000 miles away. According to reports, the EMP interrupted radio broadcasts, caused streetlights to malfunction and burglar alarms to sound, and resulted in electronic failures across the islands despite their great distance from the test site. 3

Little has been done to protect electrical systems from this threat beyond the nation's nuclear war-fighting infrastructure. The reason: During the Cold War, only the Soviet Union had the ability to mount an EMP attack against the United States, and if it had launched such an attack, the result would have been nuclear war. It made no sense to spend money to protect civil infrastructure from an electromagnetic pulse since little would be left standing after a nuclear bomb landed on U.S. soil.

Today, because of the spread of nuclear technology and ballistic missiles, the threat of a high-altitude EMP explosion over the United States or a battlefield is increasing. Indeed, America's reliance on advanced electronics makes its systems more vulnerable to such a blast than those of hostile states that might choose to use an EMP. Moreover, protecting all of America's civilian electronic infrastructure is fiscally not feasible. Because the most likely vehicles for delivering such a nuclear device above the atmosphere are ballistic missiles, the most prudent method of protecting America from EMP attacks would be a missile defense system that could destroy a ballistic missile before it reaches U.S. airspace.

Under what circumstances would an EMP attack on the United States be likely to occur? The possible scenarios range from one involving a rogue state's desire to demonstrate its potential ability to strike U.S. territory with a nuclear bomb to one in which such a state wants to give itself an advantage in a regional conflict by crippling U.S. military and allied forces, which are more dependent on advanced electronics and therefore more susceptible to an EMP attack.

Congress is well aware of the increasing threat. The Senate will have an opportunity to address the vulnerability of military and civilian systems to such an attack when it considers the fiscal year (FY) 2001 defense authorization bill (H.R. 4205) passed by the House on May 18. Representative Roscoe Barlett (R-MD) authored a provision of this bill (Title XIV) to establish a Commission to Assess the Threat to the United States from Electromagnetic Pulse (EMP) Attack. This would be an important first step.

In addition, Congress should hold hearings to establish what missile defense system could intercept ballistic missiles armed with nuclear warheads that could be detonated above the atmosphere, and it should continue to press the Administration to proceed quickly toward the deployment of an effective national missile defense system.
UNDERSTANDING THE EMP THREAT

The scientific principles behind generating a high-altitude electromagnetic pulse are relatively easy to understand. A nuclear weapon is detonated between 25 miles and 300 miles above the Earth's surface; the radiation reaching the atmosphere interacts with air molecules to produce high-energy electrons that speed across the Earth's magnetic field as an instantaneous, invisible electromagnetic pulse. 4 A nuclear device must be detonated above the Earth's atmosphere in order to generate the high-altitude EMP effects.

An EMP can have devastating consequences for developed countries, because any metallic conductor in the area affected becomes a "receiver" for the powerful energy burst released by the blast. Such receivers include anything with electronic wiring--from airplanes and automobiles to computers, railroad tracks, and communication lines. If systems connected to these receivers are not protected, they will be damaged by the intense energy pulse. Indeed, depending on the strength of the pulse and the vulnerability of the equipment, the effects could range from interrupted phone conversations and radio interference to the melting of components in every type of electrical system.

An EMP damages unprotected electronic equipment within the blast's "line of sight." The size of the area in harm's way (the EMP's "footprint" on the Earth's surface) is determined by the altitude of the explosion. The higher the altitude, the greater the land area affected (see Map 1). A Scud-type ballistic missile launched from a vessel off the U.S. coast and detonated at an altitude of 95 miles would degrade electronic systems across one-fourth of the United States. A Taepo Dong-2 missile launched from North Korea probably could deliver a warhead 300 miles above America--enough to degrade electronic systems throughout the country. Crude weapons with low yields, like those used against Japan in World War II, would have ample power to cripple the United States.



Possible EMP Scenarios

Although the threat that an enemy would use a high-altitude EMP against America existed during the Cold War, the likelihood that this could happen may be greater today. 5 During the Cold War, an EMP attack was viewed as the first step in launching a nuclear war, but it was never tried because the threat of massive nuclear retaliation provided an effective deterrent. This principle holds true today for an attack by Russia or China on the United States.

In the post-Cold War years, the proliferation of weapons of mass destruction makes the threat more difficult to assess. More important, the traditional deterrent of retaliation does not apply. No rogue nation has the capacity to fight a general nuclear war with the United States; therefore, it is not likely that an EMP blast would be used as a precursor to full-scale war. And since an EMP blast is not likely to kill anyone directly or to be followed by a nuclear strike that would annihilate U.S. cities, the United States is less likely to retaliate and destroy an entire nation of innocent people as punishment for the decisions of a rogue leader. The motivation for a rogue state to use its limited nuclear arsenal in an EMP strike against the United States is simple: It maximizes the impact of its few warheads while minimizing the risk of retaliation.

This decrease in risk for rogue leaders could compel them to use EMP to offset overwhelming U.S. conventional power on the battlefield. An EMP blast would debilitate U.S. forces in a hot spot where they might be deployed and throughout a region of strategic interest, such as Northeast Asia or the Middle East. Because the United States has no policy on deterrence for a rogue state's use of high-altitude EMP, and because EMP attacks are less risky for those states, such attacks are far more likely to occur in this era of nuclear proliferation than they were at any time during the Cold War.

The national missile defense architecture planned by the Administration, with 100 ground-based interceptors stationed at one site in Alaska, may be unable to intercept a nuclear warhead before it detonates above U.S. territory, and it would have virtually no chance of intercepting such a missile above a theater of combat.

Consider these possible scenarios.

Scenario #1: A rogue-state leader decides to launch an EMP attack on the United States to improve the odds of winning a regional conflict. After obtaining an ICBM equipped with a nuclear warhead, Saddam Hussein decides to invade Kuwait again. 6 The United States is called upon to liberate its ally. A few weeks into the war, Saddam launches a ballistic missile armed with a nuclear warhead toward the United States. It is detonated 50 miles above a section of the American West. Although no people are harmed, there is a regional blackout. Saddam Hussein gloats, having leveled the playing field and weakened U.S. resolve by demonstrating his ability to deliver a nuclear weapon to U.S. soil. The President refuses to launch a counter nuclear attack out of fear that it would kill millions of innocent people.

Jack Spencer is Policy Analyst for Defense and National Security in the Kathryn and Shelby Cullom Davis Institute for International Studies at The Heritage Foundation.


Last Edited by theDtrain on 03/01/2012 05:43 PM