Secondary School Level

The possibility of using nuclear weapons in war is usually divided into two subgroups, each with different effects and potentially fought with different types of nuclear armaments. The first, a limited nuclear war (sometimes attack or exchange), refers to a small scale use of nuclear weapons by one or more parties. A "limited nuclear war" would most likely consist of a limited exchange between two nuclear superpowers targeting each other's military facilities, either as an attempt to pre- emotively cripple the enemy's ability to attack as a defensive measure or as a prelude to an invasion by conventional forces as an offensive measure. It will also refer to a nuclear war between minor nuclear powers, who lack the ability to deliver a decisive strike. This term would apply to any limited use of nuclear weapons, which may involve either military or civilian targets.

The second, a full-scale nuclear war, consists of large numbers of weapons used in an attack aimed at an entire country, including both military and civilian targets. Such an attack would seek to destroy the entire economic, social, and military infrastructure of a nation by means of an overwhelming nuclear attack.

Even the most optimistic predictions of the effects of a major nuclear exchange foresee the death of millions of civilians within a very short amount of time; more pessimistic predictions argue that a full-scale nuclear war could bring about the extinction of the human race or its near extinction with a handful of survivors (mainly in remote areas) reduced to a pre-medieval quality of life and life expectancy for centuries after and cause permanent damage to most complex life on the planet, Earth's ecosystems, and the global climate, particularly if predictions of nuclear winter are accurate. It is in this latter mode that nuclear warfare is usually alluded to as a doomsday scenario.

The United States is the only nation to have ever used nuclear weapons during war, using two atomic bombs on the Japanese cities of Hiroshima and Nagasaki in 1945. After the bombings of Japan, it was unclear exactly what status the atomic bomb would have for international relations or military actions. It was believed that atomic weapons could offset the superior forces that the Soviet Union had in Eastern Europe, and possibly be used to pressure Soviet leader Joseph Stalin into concessions. Despite Stalin's palpable fear of the bomb, he too was pursuing his own atomic capabilities at full speed.

For several years after World War II, the US developed and maintained a strategic force based on the Convair B- 36 bomber that would be able to attack any potential enemy from bomber bases in the US. It deployed atomic bombs around the world for potential use in conflicts. Over a period of a few years, many in the US defense community became increasingly convinced of the invincibility of the United States to a nuclear attack. Indeed, it became generally believed that the threat of nuclear war would deter any strike against the United States.

With the monopoly over nuclear technology broken, world-wide nuclear proliferation accelerated. The United Kingdom tested its first independent atomic bomb in 1952, followed by France in 1960 and then the People's Republic of China in 1964. While much smaller than the arsenals of the USA and the USSR, Western Europe's nuclear reserves were nevertheless a significant factor in strategic planning during the Cold War.

A key development in nuclear warfare in the 2000 "s has been the proliferation of nuclear weapons to the developing world, with Pakistan and India both publicly testing nuclear devices and North Korea conducting an underground nuclear test on October 9, 2006. The U.S. Geological Survey measured a 4.2 magnitude earthquake in the area where the test occurred. Iran, meanwhile, has embarked on a nuclear program which, while officially for civilian purposes, has come under scrutiny by the United Nations and individual states.

Recent studies undertaken by the CIA cite the enduring India-Pakistan conflict as the most likely to escalate into nuclear war. During the Kargil War in 1999, Pakistan came close to using their nuclear weapons in case of further deterioration. (BBC) In fact, Pakistan's foreign minister had even warned that they would "use any weapon in our arsenal", hinting at a nuclear strike against India; the statement was condemned by the international community with Pakistan denying it later on. It remains the only war between two declared nuclear powers. The 2001-2002 India-Pakistan standoff again stoked fears of nuclear war between the two countries.

A study presented at the annual meeting of the American Geophysical Union in December 2006 asserted that even a small-scale, regional nuclear war could produce as many direct fatalities as all of World War II and disrupt the global climate for a decade or more. In a regional nuclear conflict scenario where two opposing nations in the subtropics would each use 50 Hiroshima-sized nuclear weapons (ca. 15 kiloton each) on major populated centers, the researchers estimated fatalities from 2.6 million to 16.7 million per country. Also, as much as five million tons of soot would be released, which would produce a cooling of several degrees over large areas of North America and Eurasia, including most of the grain-growing regions. The cooling would last for years and could be "catastrophic" according to the researchers.

However, this sub-strategic capacity has been criticized as potentially increasing the acceptability of using nuclear weapons. The related consideration of new generations of limited yield battlefield nuclear weapons by the United States has also alarmed anti-nuclear groups, who believe it will make the use of nuclear weapons more acceptable.