Excessive secrecy prohibits the public from knowing the exact number of nuclear
weapons in the world. Each nation shields the details of its own nuclear arsenal and
generally knows few precise details about the size and composition of other
countries' stockpiles.
Despite the uncertainty, we know that the total global nuclear weapons stockpile is
considerably smaller than the 1986 Cold War high of 70,000-plus warheads. Through a
series of arms control agreements and unilateral decisions, nuclear weapon states
have reduced the global stockpile to its lowest level in 45 years. In the same
period, the number of nuclear weapon states has grown from three to nine.
We estimate that these nine states possess about 27,000 intact nuclear warheads, of
which 97 percent are in U.S. and Russian stockpiles. About 12,500 of these warheads
are considered operational, with the balance in reserve or retired and awaiting
dismantlement. We are able to make our estimates by monitoring all known nuclear
weapon developments, by studying long-term trends, and by tracking the
implementation of arms control treaties.
Estimating the arsenal sizes of the smaller nuclear powers–Israel, India,
Pakistan, and North Korea–poses special difficulties, considering how
minuscule they are compared with Russian and U.S. stockpiles. India and Pakistan
have about 110 nuclear warheads between them, fewer than the number of warheads
carried on a single U.S. Trident submarine, and the North Koreans could have around
10. Though Israel has not acknowledged it possesses nuclear weapons, the Defense
Intelligence Agency (DIA) estimates it has between 60 and 85 warheads.
More than 128,000 nuclear warheads have been built since 1945, according to our
calculations, and all but close to 3 percent were built by the United States (about
55 percent) and the Soviet Union/Russia (about 43 percent). Since the end of the
Cold War, the United States and Russia have moved an increasing percentage of their
warheads from operational status to various reserve, inactive, or contingency
categories, as arms control agreements traditionally have not required the
destruction of warheads. For example, the 2002 Strategic Offensive Reductions Treaty
(the “Moscow Treaty”) contains no verification provisions and
ignores nonoperational and nonstrategic warheads altogether. With any number of
warheads in indeterminate status, nuclear stockpiles are becoming more opaque and
difficult to describe with precision. It's a situation that will only
worsen after 2009 if the United States and Russia do not extend the Strategic Arms
Reduction Treaty I, which requires biannual reporting on the status of
intercontinental ballistic missiles, submarine-launched ballistic missiles (SLBMs),
and bombers.
United States. The Pentagon has custody of approximately 10,000
stockpiled warheads, of which about 5,735 are considered active or operational. The
remaining are categorized as reserve or inactive. Details from an Energy Department
2004 stockpile plan indicate that some 4,000 warheads will eventually be retired,
returned to Energy's custody, and disassembled at the Pantex Plant near
Amarillo, Texas, though that task could take many years to accomplish.
Refurbishments and upgrades to existing warheads will take priority over disassembly
in terms of man-hours for the foreseeable future.
Sticking to their nukes: The leaders of four of the five major nuclear weapon
states—French President Jacques Chirac, Russian President
Vladimir Putin, President George W. Bush, and British Prime Minister Tony
Blair (left to right)—at a NATO summit.
Of the more than 70,000 warheads produced by the United States since 1945, more than
60,000 have been disassembled by mid-2006. More than 13,000 of these warheads have
been taken apart since 1990, but Energy retains more than 12,000 intact plutonium
pits from dismantled warheads and stores them at Pantex.
Russia. Moscow has released very little information about the size of
its stockpile, and its future plans are not known with a great deal of certainty. We
estimate that since 1949 the Soviet Union/Russia produced some 55,000 nuclear
warheads and that about 30,000 warheads existed in 1991 at the end of the Cold War.
A few statements from Russian officials provide an occasional benchmark to help
roughly calculate stockpile size and trends. But these statements typically lack
detail, and the referenced dates are often ambiguous. In 1993, Victor Mikhailov,
then minister of atomic energy, revealed that in 1986 the Soviet Union had 45,000
warheads in its stockpile. A decade later, Mikhailov said that nearly half of these
warheads had been dismantled.
The Defense Department and the CIA estimated that Russia dismantled slightly more
than 1,000 warheads per year during the 1990s, though how firm those estimates were
is unknown. Of the 16,000 intact warheads we estimate to be in Russia's
possession today, around 5,830 are considered operational. Because Russia has
removed warheads from its deployed and operational forces faster than it could
dismantle them, there is a backlog of warheads awaiting dismantlement. The Moscow
Treaty limits Russia's “operationally deployed strategic
warheads” to no more than 2,200 by 2012, but its arsenal could shrink
below this limit. Russia's production of new systems has been slow, and
it is uncertain whether it can maintain such a large number of warheads because of
limited resources and funding. Russia had previously pressed for a limit of 1,500
operational strategic warheads as part of the treaty, but the United States rejected
this limit.
Britain. Since 1953, Britain has produced approximately 1,200 warheads,
according to our estimates. The British arsenal peaked in the 1970s at 350 warheads
and has mostly declined since. The current stockpile consists of some 200 strategic
and “sub-strategic” warheads for delivery by Trident II SLBMs
aboard Vanguard-class nuclear-powered ballistic missile submarines (SSBNs). The
Labour government declared in July 1998 that it would maintain “fewer
than 200 operationally available warheads,” of which 48 would be on
patrol at any given time on a single SSBN.
France. The current French stockpile includes approximately 350
warheads, down from some 540 in 1992. We estimate that France produced more than
1,260 nuclear warheads since 1964. In the past decade, France dismantled its
land-based ballistic missiles and retired its nuclear bombs intended for delivery by
naval strike aircraft. France initially planned to arm its M51 sea-launched
ballistic missile, which is scheduled for deployment in 2010, with an entirely new
warhead, the Tête Nucléaire Océanique (TNO), but
the missile will instead be equipped with a more robust version of an existing
design, probably the TN-75.
China. We estimate that China has an arsenal of some 200 nuclear
warheads, down from an estimated 435 in 1993. This change is due to new information
about the arsenal. China is thought to have produced some 600 nuclear warheads since
1964, and U.S. intelligence and defense agencies predict that over the next decade,
China may increase the number of warheads targeted primarily against the United
States from 20 to about 75-100.
India and Pakistan. Neither India nor Pakistan has released any official
information to the public about the size of its nuclear arsenal. Combined, the two
are thought to possess as many as 110 warheads, some of which may not be
operationally deployed. Independent experts estimate that India has produced enough
fissile material for between 60 and 105 nuclear warheads but may have assembled only
50-60 warheads. In contrast, these experts believe that Pakistan has produced
fissile material sufficient for between 55 and 90 weapons and has assembled 40-50
warheads. Both countries are thought to be increasing their stockpiles.
Israel. Although Israel has neither confirmed nor denied that it
possesses nuclear weapons, the DIA concluded in 1999 that Israel had produced 60-80
warheads. Israel is estimated to have produced enough fissile material for between
115 and 190 warheads. The DIA projected that Israel's stockpile would
increase only modestly by 2020.
North Korea. North Korea has a 5-megawatt-electric (MWe)
graphite-moderated, gas-cooled reactor that began operations in 1986. Independent
experts estimate that it has produced about 43 kilograms of separated plutonium,
give or take 10 kilograms. Depending upon the North Koreans' technical
capability and the desired yield of the bomb, Pyongyang could have as few as five
weapons or as many as fifteen. Ten weapons seems to be a reasonable estimate, with
the addition of about one weapon per year. It is unknown if North Korea has
weap-onized its nuclear capability and made a deliverable or usable weapon that can
be mated to a missile, for example. If North Korea completes an under-construction
50 MWe reactor in a few years, it could produce about 60 kilograms of plutonium per
year, which could potentially grow the stockpile by 10-15 weapons per year.
As outlined in the Nuclear Non-Proliferation Treaty
The future. All five original nuclear weapon states continue to insist
that nuclear weapons are essential to their national security, which translates into
substantial global nuclear weapon stockpiles for the foreseeable future and the
possibility that more nations will want the Bomb as well. India has committed to
possessing a triad of nuclear forces including land-based ballistic missiles,
nuclear-capable aircraft, and sea-based missiles that will probably require an
arsenal of 100-150 warheads. Not to be outdone, Pakistan will likely keep pace with
a similarly sized arsenal. Whether Israel's nuclear arsenal remains
opaque will likely depend on the development of Iran's nuclear program,
which appears to be about three to ten years away from joining the nuclear weapon
club. Despite nuclear weapon states' progress in reducing global
stockpiles, convincing nations to abandon their nuclear arsenals altogether remains
a formidable task, one that will likely remain impossible until the nuclear powers
themselves renounce their weapons.
Supplementary Material
Treaty Between the United States of America and the Russian Federation on
Strategic Offensive Reductions (SORT/Treaty of Moscow)
