Global Risk

US Nuclear Stockpile Numbers Published Enroute To Hiroshima

05.26.16 | 6 min read | Text by Hans Kristensen

The mushroom cloud rises over Hiroshima on August 6, 1945, as the city is destroyed by the first nuclear weapon ever used in war.

By Hans M. Kristensen

Shortly before President Barack Obama is scheduled to arrive for his historic visit to Hiroshima, the first of two Japanese cities destroyed by U.S. nuclear bombs in 1945, the Pentagon has declassified and published updated numbers for the U.S. nuclear weapons stockpile and warhead dismantlements.

Those numbers show that the Obama administration has reduced the U.S. stockpile less than any other post-Cold War administration, and that the number of warheads dismantled in 2015 was lowest since President Obama took office.

The declassification puts a shadow over the Hiroshima visit by reminding everyone about the considerable challenges that remain in reducing excessive nuclear arsenals – not to mention the daunting goal of eliminating nuclear weapons altogether.

Obama’s Stockpile Reductions

The declassified data shows that the stockpile as of September 2015 included 4,571 warheads. That means the Obama administration so far has reduced the stockpile by 702 warheads (or 13 percent) compared with the last count of the Bush administration.

Although 702 warheads is no small number (other than Russia, no other nuclear-armed state has more than 300 warheads), the reduction constitutes the smallest reduction of the stockpile achieved by any previous post-Cold War administration (see table).


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The declassified 2015 number is about 100 warheads lower than the number we estimated in our latest Nuclear Notebook. The reason for the difference is that the number of warheads retired in 2014-2015 turned out to be higher than the average retirement in the previous three-year period. The increase probably reflects a quicker than anticipated retirement of excess warheads for the navy’s Trident missiles.

It can be deceiving to assess stockpile reduction performance by only comparing numbers of warheads. After all, there are significantly fewer warheads left in the stockpile today compared with 1991 (in fact, 14,437 warheads fewer!) so why wouldn’t the Obama administration be retiring fewer warheads than previous post-Cold War administrations?

To overcome that bias we also compare the reductions in terms of the percentage the stockpile size changed during the various administrations. But even so, the Obama administration’s performance comes in significantly below that of all other post-Cold War administrations (see table).


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Obama’s Dismantlements

The declassified numbers also show that the Obama administration last year only dismantled 109 retired warheads. This is the lowest number of warheads dismantled in any year President Obama has been in office. And it appears to be the lowest number dismantled by the United States in one year since at least 1970.

The National Nuclear Security Administration (NNSA) says the poor performance in 2015 was due to “safety reviews, unusually high lightning events, and a worker strike at Pantex.”

But the decrease cannot be explained simply as disturbances. Although 2015 was unusually low, the Obama administration’s dismantlement record clearly shows a trendline of fewer and fewer warheads dismantled (see table).


Nuclear warhead dismantlement has decreased during the Obama administration. Click to view full size

There are currently roughly 2,300 retired warheads awaiting dismantlement, most of which were retired prior to 2009. NNSA says it plans to “increase weapons dismantlement by 20 percent starting in FY 2018” to be able to complete dismantlement of warheads retired prior to 2009 before the end of September 2021.

With the Obama administration’s average of about 280 warheads dismantled per year, it will take at least until 2024 before the total current backlog is dismantled. The several hundred additional warheads that will be retired before then will take several additional years to dismantle.

Yet in the same time period NNSA has committed to several other big warhead jobs that will compete with dismantlement work over the capacity at Pantex, including: complete production of the W76-1 by 2019, start up production of the B61-12 and W88 Alt 370 in 2020, preparation for the start up of the W80-4 in 2025, as well as the ongoing disassembly and reassembly for inspection of the existing warhead types in the stockpile.

Conclusion and Recommendations

President Obama’s visit to Hiroshima takes place in the shadow of his nuclear weapons legacy: he has reduced the U.S. nuclear weapons stockpile less than any other post-Cold War president and nuclear warhead dismantlement has declined on his watch.

For the arms control community (and that includes several important US allies, including Japan) the Obama administration’s modest performance on reducing the number of nuclear weapons – despite the New START Treaty – is a disappointment. Not least because the administration’s nuclear weapons modernization program has been anything but modest.

To be fair, it is not all President Obama’s fault. His vision of significant reductions and putting an end to Cold War thinking has been undercut by opposition ranging from Congress to the Kremlin. An entrenched and almost ideologically opposed Congress has fought his arms reduction vision every step of the way. And the Russian government has rejected additional reductions while New START is being implemented (although we estimate Russia during the Obama administration has reduced its own stockpile by more than 1,000 warheads).

Ironically, although Congress is vehemently opposed to additional nuclear reductions – certainly unilateral ones, the modernization plan Congress has approved has significant unilateral nuclear reductions embedded in it: a reduction of nuclear gravity bombs by one-half, a reduction of 48 sea-launched ballistic missiles beyond what’s planned under the New START Treaty, and unilateral reduction in the late-2020s of excess W76 warheads.


The Air Force wants to build a new and better nuclear air-launched cruise missile even though the mission can be covered by conventional cruise missiles or other nuclear weapons. President Obama should cancel or delay the program and pursue a global ban on nuclear cruise missiles.

Curiously, there seems to have been less resistance to stockpile reductions from the U.S. military. The Pentagon’s Defense Strategic Guidance from 2012, for example, concluded: “It is possible that our deterrence goals can be achieved with a smaller nuclear force, which would reduce the number of nuclear weapons in our inventory as well as their role in U.S. national security strategy.”

Likewise, the Pentagon’s Nuclear Employment Strategy report sent to Congress in 2013 concluded that the nuclear force levels in place when the New START Treaty is fully implemented in 2018 “are more than adequate for what the United States needs to fulfill its national security objectives,” and that the United States “can ensure the security of the United States and our Allies and partners and maintain a strong and credible strategic deterrent while safely pursuing up to a one-third reduction in deployed nuclear weapons from the level established in the New START Treaty.”

And despite a significant turn for the worse in East-West relations, Russia is not increasing its nuclear arsenal but continuing to reduce it. But even if President Vladimir Putin decided to break out from the New START Treaty, the Pentagon concluded in 2012, Russia “would not be able to achieve a militarily significant advantage by any plausible expansion of its strategic nuclear forces, even in a cheating or breakout scenario under the New START Treaty, primarily because of the inherent survivability of the planned U.S. Strategic force structure, particularly the OHIO-class ballistic missile submarines, a number of which are at sea at any given time.” (Emphasis added.)

Those conclusions reveal a significant excess capacity in the U.S. nuclear arsenal that provides plenty of room for President Obama to do more in Hiroshima than simply remind of the dangers of nuclear weapons and reiterate the long-term vision of a world without them. Steps that he could and should take before leaving office include:

These actions would help bring U.S. nuclear policy back on track, remove excess capacity in the nuclear arsenal, restore the credibility of its arms control policy, retain a Triad of long-range nuclear forces, provide plenty of reassurance to allies and friends, maintain strategic stability, and free up resources for conventional forces. If Obama doesn’t do it, President Hillary Clinton will have to clean up after him.

This publication was made possible by a grant from the New Land Foundation and Ploughshares Fund. The statements made and views expressed are solely the responsibility of the author.