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Seeking to forestall a global nuclear war, the 1968 Nuclear Nonproliferation Treaty (NPT) formally divided the world into “nuclear weapon states” and “nonnuclear weapon states.” Resentment and suspicion between the nuclear “haves” and “have-nots” have lingered ever since. Today, in addition to the five official nuclear powers, three others – India, Pakistan, and now, North Korea – have sidestepped the NPT and publicly conducted nuclear weapon tests. And though it has never confirmed it, Israel is widely believed to have a nuclear weapons program outside the NPT. The NPT and other treaties have kept the number of nuclear states from rising to the doomsday level predicted by President John F. Kennedy. But a long list of nuclear aspirants remains and with North Korea’s recent nuclear test and Iran’s uranium enrichment activities, the treaty faces new stresses.
How large is the world’s nuclear arsenal?
The global nuclear arms race reached its peak in 1986 with the five nuclear powers accumulating more than 70,000 nuclear warheads. The number of intact nuclear warheads has since declined to about 27,000, according to a global Bulletin of the Atomic Scientists nuclear stockpile report prepared by Robert S. Norris of the Natural Resources Defense Council and Hans M. Kristensen, of the Federation of American Scientists. The vast majority of these warheads belong to the United States and Russia.
Who are the world’s nuclear powers?
The first five countries to develop and test nuclear weapons, the “Big Five,” wield United Nations Security Council veto power in addition to having nuclear arsenals.
- United States is believed to have more than 10,000 nuclear warheads, down from its Cold War peak of 24,401. Paired with intercontinental ballistic missiles like the Minuteman, each of these nuclear warheads can deliver an estimated 400-kiloton blast to targets 7,800 miles from U.S. launch sites, according to the Center for Defense Information. The air and sea legs of the United States nuclear triad also remain strong, with Trident submarine-launched ballistic missiles patrolling the U.S. coastline and bombers like the B-52, capable of carrying 20 cruise missiles at a time, stationed at inland air force bases. As per agreements with Russia, the Pentagon is gradually de-commissioning its arsenal, but continues to introduce upgrades to its weapons program including new targeting, guidance, and propulsion systems. The U.S. bombing of the Japanese cities of Hiroshima and Nagasaki in 1945 remain the only cases of atomic weapons used against another country.
- Russia, which conducted its first nuclear test in 1949, has an estimated 16,000 nuclear warheads, down 64 percent from 45,000 in 1986. The liquidation of Russia’s stockpile has as much to do with complying with its agreements with the United States as it does with the cost of maintaining its weapons system. The Center for Defense Information estimates that as many as 11,000 of Russia’s remaining warheads are stockpiled and not paired with delivery systems. But its maritime, air, and ground-based arsenal remains the world’s largest -- with such systems as the hulking Satan SS-18 intercontinental ballistic missiles combining a 20-megaton yield and an 6,600-mile range.
- Britain conducted its first nuclear test in 1952 after collaborating with the United States and has an estimated 200 warheads, according to the Center for Defense Information. The country has phased out its air-based nuclear missile programs and now relies solely on its fleet of submarines equipped with Trident submarine-launched ballistic missiles with an 6,600-mile range and a 100-kiloton yield.
- France conducted its first nuclear test in 1960 and now has an estimated 350 warheads. The country has dismantled its surface-to-surface missile program and now maintains a two-pronged nuclear delivery system consisting of submarines and bomber planes, according to the Center for Defense Information.
- China tested its first nuclear weapon in 1964 and has accumulated an estimated 200 warheads, according to the Bulletin of the Atomic Scientists global nuclear stockpile report. China has developed a variety of nuclear delivery systems, from road-mobile intermediate range ballistic missiles to intercontinental ballistic missiles capable of striking targets in the continental United States, but is looking to shift its arsenal’s delivery system to long range missiles. A number of U.S.-based security experts predict that China is preparing to increase the number of warheads targeted primarily against the United States from twenty to as many as 100.
What other states have nuclear weapons?
In addition to the five nuclear powers, four nations have either publicly tested nuclear weapons or are widely believed to possess them.
- Israel has not acknowledged it possesses nuclear weapons, but the country is believed to have between 100 and 200 nuclear warheads and ballistic missiles that can hit targets 900 miles away in Iran and southwestern Russia. Israel has never signed the nuclear nonproliferation treaty and has never publicly conducted a nuclear test.
- India conducted its first test in 1974 and most recently again in 1998 and is now believed to have enriched enough uranium for between fifty and sixty warheads. It is believed to have a number of land-based short range (under 660 miles) missiles stationed on the Pakistan border, although these missiles are not thought to be ready-armed with nuclear warheads. India has not yet developed any submarine nuclear systems and is reportedly seeking to equip its bombers with nuclear delivery systems. India has never signed the NPT, though it gained tacit approval for its nuclear program from theUnited Statesin 2005 as explained in this Backgrounder.
- Pakistan conducted its first test in 1998, two weeks after India, and is now believed to have enriched enough uranium for between forty and fifty nuclear warheads to pair with short range ballistic missiles. Additionally, the country may have developed between five and ten intermediate range missiles, designed to hit targets up to 900 miles away. Pakistan has never signed the NPT.
- North Korea conducted its first test in October of 2006 and is believed to have the capacity to develop between five and fifteen warheads. North Korea backed out of the NPT in 2003. Its first test triggered a 4.2 tremor on the Richter scale, leading experts to estimate the test bomb’s yield at less than one kiloton.
Which states relinquished their nuclear weapons programs?
- South Africa built six air-based nuclear weapons but terminated its nuclear weapons program in 1991, dismantling the weapons and signing onto the NPT as a nonnuclear weapon state.
- Libya bought nuclear technology blueprints from Pakistan’s A.Q. Khan and unsuccessfully attempted to enrich imported raw uranium into weapons-grade material. In 2003, Libya pledged to give up its fledgling weapons program, adhere to the NPT as a nonnuclear weapon state, and cooperate with international inspectors.
- Former Soviet States Belarus, Kazakhstan, and Ukraine, inherited Soviet-era nuclear devices after the breakup of the Soviet Union in 1991. All three countries turned these materials over to Russia in 1993 and signed onto the NPT as nonnuclear weapon states.
- Argentina has never succeeded in building a nuclear bomb, though the country’s military regime poured funds into nuclear weapons research beginning in the 1960s. After establishing a bilateral nuclear inspection agreement with Brazil and signing the NPT as a nonnuclear weapon state in 1995, Argentina continues to develop its nuclear energy program.
- Brazil is believed to have pursued nuclear weapons research under its military regime and has built a uranium enrichment facility to supply its nuclear power plants. In the 1990s the country’s elected government abandoned its nuclear weapons program and the country signed the NPT as a nonnuclear weapon state in 1998.
- Iraq is believed to have begun a nuclear weapon research program in the 1970s but the country’s nuclear capability was effectively destroyed by the 1991 Gulf War. IAEA officials reaffirmed this in early 2003. But based in part on U.S.intelligence claims that Iraq was poised to revive its nuclear program, the United States launched an invasion against Iraq in March 2003. It has since uncovered no proof of a nuclear weapons program and the country’s new leadership has pledged not to pursue a nuclear weapon program.
What are the potential nuclear weapons states?
- Egypt is not believed to possess nuclear weapons, though the country has conducted nuclear research since the 1950s and has threatened to build a weapons program to compete with Israel’s suspected arsenal. In 1968, Egypt signed the NPT as a nonnuclear weapon state but has since been a leading critic of the treaty’s unequal premise.
- Iran, a signatory of the NPT, claims to be enriching uranium to fuel a civilian nuclear power plant currently under construction but observers worry Iran is pursuing a clandestine nuclear weapons program. Experts estimate Iran is still at least 9 years away from developing a nuclear weapon, but are keeping a close eye on Tehran’s reaction to the North Korea test as this Backgrounder explains.
- Japan is forbidden under its constitution from producing nuclear weapons, although experts believe the country is capable of rapidly developing such weapons. Japan has a highly developed civilian nuclear program which, along with its practice of recycling spent nuclear fuel into plutonium, has raised eyebrows.
- South Korea began pursuing nuclear weapons during the 1970s, but agreed to give up its fledgling program and signed the NPT in 1975. South Korea was caught violating the terms of NPT by IAEA inspectors and, in 2004, confessed to extracting plutonium and enriching uranium as far back as 1981.South Korea has since agreed to cooperate with the IAEA.
- Taiwan signed the NPT in 1968 but is believed to have continued work on its covert nuclear weapons program, begun in 1964, until 1988 when its activities were discovered by IAEA inspectors. Taiwan has reportedly forsaken its weapons program, in part because of U.S. pressure, but is believed to have the expertise to develop nuclear weapons.
What are the major treaties governing nuclear weapons and testing?
The primary treaty governing nuclear weapons remains the NPT, but its authority is supplemented by other bilateral and multilateral agreements.
- Nuclear Nonproliferation Treaty signed by 188 nations, this 1968 treaty separates the world’s nuclear “haves” and “have nots.” The treaty’s five nuclear weapon states agree not to transfer nuclear weapons or weapons technology to the nonnuclear weapon states and nonnuclear states accordingly agree not to build or acquire nuclear weapons. The treaty also allows for the “fullest possible exchange” of peaceful nuclear technology with the understanding that states pursuing nuclear energy programs agree to inspections by the International Atomic Energy Agency. The treaty’s authority is strained by the actions of Israel, India, and Pakistan --which have never signed the treaty -- and North Korea. And while the treaty calls for the “earliest possible” end to the nuclear arms race, it includes no deadline for disarmament.
- Comprehensive Nuclear Test Ban Treaty (CTBT) of 1996, ratified by 160 nations, bans all nuclear weapons test explosions. The CTBT replaces the Partial Test Ban Treaty of 1963 which applied to the atmosphere, outer space, and under water. All five nuclear powers have signed the CTBT, but China and the United States have since failed to ratify it. Israel is another treaty signatory that has failed to ratify the the agreement. And India, Pakistan, and North Korea –which have all conducted nuclear weapons tests since 1996 -- have refused to sign the treaty. The CTBT will not enter into force until it receives the signatures of these three countries and is ratified by thirteen additional nations, including China and the United States.
- Strategic Offensive Reductions Treaty, also known as the Moscow Treaty, is a bilateral treaty between the United States and Russia. Signed in May 2002 by Presidents George W. Bush and Vladimir Putin, the treaty issues a 2012 deadline for a sizeable reduction in each country’s nuclear arsenal. Under the agreement, each country has pledged to reduce the number of “operationally deployed” strategic weapons (those weapons aimed at civilian, not military targets) to between 1,700 and 2,200.
- Anti-Ballistic Missile Treaty, signed in 1972 by the leaders of the United States and the Soviet Union, forbids the testing and use of nationwide ballistic missile defense systems. The pact was built on the premise that if either country rendered itself impervious to nuclear attacks it could trigger a full scale nuclear war. President Bush withdrew the United States from the treaty in June 2002, effectively dissolving the pact.
What role does the IAEA play in policing nuclear and nonnuclear states?
The International Atomic Energy Agency was originally established as the “Atoms for Peace” organization in 1957 and was granted inspection authority under the 1968 NPT. The agency is simultaneously charged with promoting the peaceful uses of nuclear energy and making sure civilian nuclear technology is not diverted for weapons purposes. Countries seeking to develop a nuclear energy program can receive technical assistance from the IAEA, as Iran has done with its Bushehr Nuclear Power Plant. NPT member states agree to both scheduled and unannounced IAEA inspections of all stages of their nuclear energy cycle: from uranium mines and enrichment plants, to nuclear waste sites. The IAEA also monitors nuclear facilities with surveillance cameras, conducts audits of nuclear material inventories, and limits the use of certain nuclear operations using tamper-proof seals. If violations are discovered, the agency has the power to refer the country to the UN Security Council.