View source for Nuclear warfare

{{Short description|Military conflict that deploys nuclear weaponry}}
{{redirect2|Nuclear War|Nuclear strike}}
{{redir-dist|Global Thermonuclear War|WarGames|DEFCON (video game)}}
[[File:Atomic cloud over Hiroshima.jpg|thumb|The [[mushroom cloud]] over [[Hiroshima]] following the detonation of the [[Little Boy]] nuclear bomb on 6 August 1945. The [[atomic bombings of Hiroshima and Nagasaki]] remain the first and only wartime uses of nuclear weapons in history.]]
{{War |weapons |width=23.0em}}
{{Nuclear weapons |width=23.0em}}
{{Weapons of mass destruction}}
'''Nuclear warfare''', also known as '''atomic warfare''', is a [[War|military conflict]] or prepared [[Policy|political strategy]] that deploys [[nuclear weapon]]ry. Nuclear weapons are [[Weapon of mass destruction|weapons of mass destruction]]; in contrast to [[conventional warfare]], nuclear warfare can produce destruction in a much shorter time and can have a long-lasting [[radiological warfare|radiological result]]. A major nuclear exchange would likely have long-term effects, primarily from the [[Nuclear fallout|fallout]] released, and could also lead to secondary effects, such as "[[nuclear winter]]",<ref>{{cite book|url=http://www.nap.edu/openbook.php?record_id=940&page=155|title=7 Possible Toxic Environments Following a Nuclear War – The Medical Implications of Nuclear War 1985 – The National Academies Press|year=1986|doi=10.17226/940|pmid=25032468|isbn=978-0-309-07866-5}}</ref><ref>{{cite encyclopedia|url=https://www.britannica.com/eb/article-9056451/nuclear-winter|title=nuclear winter|encyclopedia=Encyclopædia Britannica|date=August 2023 }}</ref><ref name="Martin-1982">{{Cite journal|last=Martin|first=Brian|date=December 1982|title=The global health effects of nuclear war|url=http://www.bmartin.cc/pubs/82cab/index.html|journal=Current Affairs Bulletin|volume=59|issue=7}}</ref><ref name="bmartin.cc">{{cite web| url = http://www.bmartin.cc/pubs/82jpr.html| title = Critique of Nuclear Extinction – Brian Martin 1982}}</ref><ref name="johnstonsarchive.net">{{Cite web|url=http://www.johnstonsarchive.net/nuclear/nuclearwar1.html|title=The Effects of a Global Thermonuclear War|website=www.johnstonsarchive.net}}</ref><ref>{{cite web| url = http://trove.nla.gov.au/work/21437545?selectedversion=NBD238850| title = Long-term worldwide effects of multiple nuclear-weapons detonations. Assembly of Mathematical and Physical Sciences, National Research Council,1975.}}</ref> [[nuclear famine]], and [[societal collapse]].<ref name=Ehrlich>{{cite journal |last1=Ehrlich |first1=P. R.|first2=J. |last2=Harte |first3=M. A. |last3=Harwell |first4=P. H. |last4=Raven |first5=C. |last5=Sagan |first6=G. M. |last6=Woodwell |first7=J. |last7=Berry |first8=E. S. |last8=Ayensu |first9=A. H. |last9=Ehrlich |first10=T. |last10=Eisner |first11=S. J. |last11=Gould |first12=H. D. |last12=Grover |first13=R. |last13=Herrera |first14=R. M. |last14=May |first15=E. |last15=Mayr |first16=C. P. |last16=McKay |first17=H. A. |last17=Mooney |first18=N. |last18=Myers |first19=D. |last19=Pimentel |first20=J. M. |last20=Teal |name-list-style=amp |date= 1983|title=Long-term biological consequences of nuclear war|journal=Science |volume=222 |issue= 4630|pages=1293–1300 |doi=10.1126/science.6658451|pmid= 6658451|bibcode=1983Sci...222.1293E}}</ref><ref>{{cite web|url=http://www.thebulletin.org/content/doomsday-clock/overview|title=Overview of the Doomsday Clock|work=Bulletin of the Atomic Scientists}}</ref><ref>The Nuclear Winter: The World After Nuclear War, Sagan, Carl et al., Sidgwick & Jackson, 1985</ref> A global thermonuclear war with [[Cold War]]-era stockpiles, or even with the current smaller stockpiles, may lead to various scenarios including [[human extinction]].<ref>{{cite journal |author=Tonn, Bruce |author2=MacGregor, Donald |name-list-style=amp |doi=10.1016/j.futures.2009.07.009 |title=A singular chain of events |journal=Futures |volume=41 |issue=10 |year=2009 |pages=706–714|s2cid=144553194 }}</ref>

To date, the only use of nuclear weapons in armed conflict occurred in 1945 with the American [[atomic bombings of Hiroshima and Nagasaki]].<ref name=":0">{{Cite web |last=Tannenwald |first=Nina |title='Limited' Tactical Nuclear Weapons Would Be Catastrophic |url=https://www.scientificamerican.com/article/limited-tactical-nuclear-weapons-would-be-catastrophic/ |access-date=2025-04-10 |website=Scientific American |language=en}}</ref> On August 6, 1945, a [[uranium]] [[Nuclear weapon design|gun-type]] device (code name "[[Little Boy]]") was detonated over the [[Empire of Japan|Japanese]] city of [[Hiroshima]]. Three days later, on August 9, a [[plutonium]] [[Nuclear weapon design|implosion-type]] device (code name "[[Fat Man]]") was detonated over the Japanese city of [[Nagasaki]]. Together, these two bombings resulted in the deaths of approximately 200,000 people and contributed to the [[surrender of Japan]], which occurred before any further nuclear weapons could be deployed.

After [[World War II]], nuclear weapons were also developed by the [[Soviet atomic bomb project|Soviet Union]] (1949), the [[United Kingdom]] (1952), [[France]] (1960), and the People's Republic of [[China]] (1964), which contributed to the state of conflict and extreme tension that became known as the [[Cold War]]. In 1974, [[India]], and in 1998, [[Pakistan]], two countries that were openly hostile toward each other, developed nuclear weapons. [[Israel]] (1960s) and [[North Korea]] (2006) are also thought to have developed stocks of nuclear weapons, though it is not known how many. The Israeli government has never admitted nor denied having nuclear weapons, although it is known to have constructed the reactor and reprocessing plant necessary for building nuclear weapons.<ref>{{cite book|last1=Hersh|first1=Seymour|title=The Samson Option|date=1991|publisher=Random House|isbn=0-394-57006-5|page=130}}</ref> [[South Africa]] also manufactured several complete nuclear weapons in the 1980s, but during the 1990s, it subsequently became [[South Africa and weapons of mass destruction|the first country to voluntarily destroy its domestically made weapons stocks]] and abandon further nuclear weapon production.<ref>{{Cite web |last=Albright |first=David |title=South Africa's Nuclear Weapons Program |url=https://web.mit.edu/SSP/seminars/wed_archives01spring/albright.htm |website=MIT.edu}}</ref><ref>{{Cite web |title=South Africa: Why Countries Acquire and Abandon Nuclear Bombs |url=https://world101.cfr.org/global-era-issues/nuclear-proliferation/south-africa-why-countries-acquire-and-abandon-nuclear#:~:text=On%20March%2024%2C%201993%2C%20in,South%20Africa%20gave%20them%20up. |website=World101| date=27 July 2023 }}</ref> Nuclear weapons have been detonated on over 2,000 occasions for [[Nuclear weapons testing|testing purposes]] and demonstrations.<ref name='1945-1998'>{{cite web|url=http://www.ctbto.org/specials/1945-1998-by-isao-hashimoto/|title="1945–1998" by Isao Hashimoto|access-date=2015-03-16|archive-date=2018-07-06|archive-url=https://web.archive.org/web/20180706161741/https://www.ctbto.org/specials/1945-1998-by-isao-hashimoto/|url-status=dead}}</ref><ref name='Tally'>{{Cite web|url=https://www.armscontrol.org/factsheets/nucleartesttally|title=The Nuclear Testing Tally &#124; Arms Control Association|website=www.armscontrol.org}}</ref>

After the [[dissolution of the Soviet Union]] in 1991 and the resultant end of the Cold War, the threat of a major nuclear war between the [[Superpower|two nuclear superpowers]] was generally thought to have declined.<ref>{{cite journal |first=Robert A. |last=Denemark |title=Nuclear War in the Rivalry Phase of the World-System |journal=Journal of World-Systems Research |date=14 August 2018 |volume=24 |issue=2
|page=349 |doi=10.5195/jwsr.2018.749 |s2cid=158444919 |url=http://jwsr.pitt.edu/ojs/index.php/jwsr/article/view/749|doi-access=free }}</ref> Since then, concern over nuclear weapons has shifted to the prevention of localized nuclear conflicts resulting from [[nuclear proliferation]], and the threat of [[nuclear terrorism]]. However, the threat of nuclear war is considered to have resurged after the [[Russian invasion of Ukraine]], particularly with regard to [[Nuclear risk during the Russian invasion of Ukraine|Russian threats to use nuclear weapons during the invasion]].<ref>{{Cite news |last1=Sanger |first1=David E. |last2=Troianovski |first2=Anton |last3=Barnes |first3=Julian E. |date=2022-10-01 |title=In Washington, Putin's Nuclear Threats Stir Growing Alarm |language=en-US |work=The New York Times |url=https://www.nytimes.com/2022/10/01/world/europe/washington-putin-nuclear-threats.html |access-date=2022-10-02 |issn=0362-4331}}</ref><ref>{{Cite news |title=Could the war in Ukraine go nuclear? |newspaper=The Economist |url=https://www.economist.com/international/2022/09/29/could-the-war-in-ukraine-go-nuclear |access-date=2022-10-02 |issn=0013-0613}}</ref>

Since 1947, the [[Doomsday Clock]] of the ''[[Bulletin of the Atomic Scientists]]'' has visualized how close the world is to a nuclear war. The Doomsday Clock reached a high point in 1953, when the Clock was set to two minutes until midnight after the U.S. and the Soviet Union began testing hydrogen bombs, and in 2018, following the failure of world leaders to address tensions relating to nuclear weapons and climate change issues.<ref>{{cite news|url=https://www.cnn.com/2018/01/25/politics/doomsday-clock-closer-nuclear-midnight/index.html|title='Doomsday clock' ticks closer to apocalyptic midnight|last=Koran|first=Laura|work=[[CNN]]|date=January 25, 2018}}</ref> Since 2025, the Clock has been set at 89 seconds to midnight, the closest it has ever been.<ref>{{Cite web |last=Treisman |first=Rachel |date=2025-01-29 |title=The Doomsday Clock has never been closer to metaphorical midnight. What does it mean? |url=https://www.npr.org/2025/01/29/nx-s1-5279204/doomsday-clock-2025-history |access-date=2025-01-24 |website=NPR |language=en}}</ref> The 2023 advance of the Clock's time setting was largely attributed to the risk of [[nuclear escalation]] that arose from the Russian invasion of Ukraine.<ref>{{Cite web |last=Spinazze |first=Gayle |date=2023-01-24 |title=PRESS RELEASE: Doomsday Clock set at 90 seconds to midnight |url=https://thebulletin.org/2023/01/press-release-doomsday-clock-set-at-90-seconds-to-midnight/ |access-date=2023-01-24 |website=Bulletin of the Atomic Scientists |language=en-US}}</ref>

==Types of nuclear warfare==
Nuclear warfare scenarios are usually divided into two groups, each with different effects and potentially fought with different types of nuclear armaments.

The first, a '''limited nuclear war'''<ref name="N.N. Sokov">{{cite book |url=http://thebulletin.org/why-russia-calls-limited-nuclear-strike-de-escalation |author=N.N. Sokov |title=Why Russia calls a limited nuclear strike "de-escalation" |publisher=Bulletin of the Atomic Scientists |date=2015 |access-date=2015-12-28 |archive-date=2020-06-09 |archive-url=https://web.archive.org/web/20200609031156/https://thebulletin.org/2014/03/why-russia-calls-a-limited-nuclear-strike-de-escalation/ |url-status=dead }}</ref> (sometimes ''attack'' or ''exchange''), refers to the controlled use of nuclear weapons, whereby the implicit threat exists that a nation can still escalate their use of nuclear weapons. For example, using a small number of nuclear weapons against strictly military targets could be escalated through increasing the number of weapons used, or escalated through the selection of different targets. Limited attacks are thought to be a more credible response against attacks that do not justify all-out  retaliation, such as an enemy's limited use of nuclear weapons.<ref>{{cite book |editor=[[Ash Carter]] |editor2=John Steinbruner |editor3=Charles Zraket |date=1987 |title=Managing Nuclear Operations |location=Washington DC |publisher=Brookings Institution |pages=123–125 |isbn=0-8157-1314-2}}</ref>

The second, a '''full-scale nuclear war''', could consist of large numbers of nuclear weapons used in an attack aimed at an entire country, including military, economic, and civilian targets. Such an attack would almost certainly destroy the entire economic, social, and military infrastructure of the target nation, and would likely have a devastating effect on Earth's biosphere.<ref name=Ehrlich/><ref>{{Cite journal|last1=Grover|first1=Herbert D.|last2=Harwell|first2=Mark A.|date=1985-10-01|title=Biological Effects of Nuclear War II: Impact on the Biosphere|journal=BioScience|language=en|volume=35|issue=9|pages=576–583|doi=10.2307/1309966|issn=0006-3568|jstor=1309966}}</ref>

Some [[Cold War]] strategists such as [[Henry Kissinger]]<ref>{{cite web|url=http://www.hrc.utexas.edu/multimedia/video/2008/wallace/kissinger_henry_t.html|title=Henry Kissinger: The Mike Wallace Interview|access-date=2010-11-24|archive-date=2020-04-03|archive-url=https://web.archive.org/web/20200403232753/http://www.hrc.utexas.edu/multimedia/video/2008/wallace/kissinger_henry_t.html|url-status=dead}}</ref> argued that a limited nuclear war could be possible between two heavily armed superpowers (such as the [[United States]] and the [[Soviet Union]]). Some predict, however, that a limited war could potentially "[[Conflict escalation|escalate]]" into a full-scale nuclear war. Others{{Who|date=April 2012}} have called limited nuclear war "global [[nuclear holocaust]] in slow motion", arguing that—once such a war took place—others would be sure to follow over a period of decades, effectively rendering the planet uninhabitable in the same way that a "full-scale nuclear war" between superpowers would, only taking a much longer (and arguably more agonizing) path to the same result.

Even the most optimistic predictions of the effects of a major nuclear exchange foresee the death of many millions of victims within a very short period of time. Such predictions usually include the breakdown of government, professional, and commercial institutions, vital to the continuation of civilization. The resulting loss of vital affordances (food, water and electricity production and distribution, medical and information services, etc.) would account for millions more deaths. More pessimistic predictions argue that a full-scale nuclear war could potentially bring about the [[human extinction]], or at least its ''near'' extinction, with only a relatively small number of survivors (mainly in remote areas) and a reduced [[quality of life]] and [[life expectancy]] for centuries afterward. However, such predictions, assuming [[total war]] with nuclear arsenals at [[Cold war|Cold War]] highs, have not been without criticism.<ref name="bmartin.cc"/> Such a horrific catastrophe as global nuclear warfare would almost certainly cause permanent damage to most complex life on the planet, its ecosystems, and the global climate.<ref name="johnstonsarchive.net"/>

A study presented at the annual meeting of the [[American Geophysical Union]] in December 2006 asserted that 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 in which two opposing nations in the [[subtropics]] each used 50 Hiroshima-sized nuclear weapons (c. 15 kiloton each) on major population centers, the researchers predicted fatalities ranging from 2.6&nbsp;million to 16.7&nbsp;million per country. The authors of the study estimated that as much as five million tons of [[soot]] could be released, producing 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.<ref>{{cite web| url = https://www.sciencedaily.com/releases/2006/12/061211090729.htm| title = ScienceDaily – Regional Nuclear War Could Devastate Global Climate}}</ref>

Either a limited or full-scale nuclear exchange could occur during an ''accidental nuclear war'', in which the use of nuclear weapons is triggered unintentionally. Postulated triggers for this scenario have included malfunctioning early warning devices and/or targeting computers, deliberate malfeasance by rogue military commanders, consequences of an accidental straying of warplanes into enemy airspace, reactions to unannounced missile tests during tense diplomatic periods, reactions to military exercises, mistranslated or miscommunicated messages, and others.

[[List of nuclear close calls|A number of these scenarios actually occurred during the Cold War]], though none resulted in the use of nuclear weapons.<ref>Alan F. Philips, [http://www.nuclearfiles.org/menu/key-issues/nuclear-weapons/issues/accidents/20-mishaps-maybe-caused-nuclear-war.htm 20 Mishaps That Might Have Started Accidental Nuclear War] {{Webarchive|url=https://web.archive.org/web/20071012030433/http://www.nuclearfiles.org/menu/key-issues/nuclear-weapons/issues/accidents/20-mishaps-maybe-caused-nuclear-war.htm |date=2007-10-12 }}.</ref> Many such scenarios have been depicted in [[nuclear weapons in popular culture|popular culture]], such as in the 1959 film ''[[On the Beach (1959 film)|On the Beach]]'', the 1962 novel ''[[Fail-Safe (novel)|Fail-Safe]]'', the 1964 film ''[[Dr. Strangelove or: How I Learned to Stop Worrying and Love the Bomb]]'', the 1983 film ''[[WarGames]]'', and the 1984 film ''[[Threads_(1984_film)|Threads]]''.

===Sub-strategic use===
{{see also|Nuclear bunker buster|Edward Teller#Decision to drop the bombs}}
The above examples envisage nuclear warfare at a strategic level, i.e., [[total war]]. However, nuclear powers have the ability to undertake more limited engagements.

"Sub-strategic use" includes the use of either "low-yield" tactical nuclear weapons, or of [[variable yield]] strategic nuclear weapons in a very limited role, as compared to exchanges of larger-yield [[strategic nuclear weapon]]s over major [[population center]]s. This was described by the UK Parliamentary [[Defence Select Committee]] as "the launch of one or a limited number of missiles against an adversary as a means of conveying a political message, warning or demonstration of resolve".<ref>UK Parliament, House of Commons, "Select Committee on Defence, Eighth Report", ''[https://publications.parliament.uk/pa/cm200506/cmselect/cmdfence/986/98605.htm]'', 20 June 2006.  Fetched from URL on 23 December 2012.</ref> It is believed that all current nuclear weapons states possess tactical nuclear weapons, with the exception of the [[United Kingdom]], which decommissioned its tactical warheads in 1998. However, the UK does possess scalable-yield strategic warheads, and this technology tends to blur the difference between "strategic", "sub-strategic", and "tactical" use or weapons. American, French and British nuclear submarines are believed to carry at least ''some'' missiles with [[dial-a-yield]] warheads for this purpose, potentially allowing a strike as low as one [[kiloton]] (or less) against a single target. Only the [[People's Republic of China]] and the [[Republic of India]] have declarative, unqualified, unconditional "[[no first use]]" nuclear weapons policies. India and Pakistan maintain only a [[credible minimum deterrence]].

Commodore [[Tim Hare]], former Director of Nuclear Policy at the [[British Ministry of Defence]], has described "sub-strategic use" as offering the Government "an extra option in the escalatory process before it goes for an all-out strategic strike which would deliver unacceptable damage".<ref>{{Cite web|url=https://publications.parliament.uk/pa/cm200506/cmselect/cmdfence/986/98605.htm#a11|title=House of Commons - Defence - Eighth Report}}</ref> However, this sub-strategic capacity has been criticized as potentially increasing the "acceptability" of using nuclear weapons. Combined with the trend in the reduction in the worldwide nuclear arsenal as of 2007 is the warhead miniaturization and modernization of the remaining strategic weapons that is presently occurring in all the declared nuclear weapon states, into more "usable" configurations. The [[Stockholm International Peace Research Institute]] suggests that this is creating a culture where use of these weapons is more acceptable and therefore is increasing the risk of war, as these modern weapons do not possess the same psychological deterrent value as the large Cold-War era, multi-megaton warheads.<ref>{{Cite web |last=Ritter |first=Karl |date=June 12, 2007 |title=Study: World powers risk atomic war |url=https://www.inquirer.com/philly/news/nation_world/20070612_Study__World_powers_risk_atomic_war.html |access-date=2022-03-07 |website=[[The Philadelphia Inquirer]] |language=en}}</ref>

In many ways, this present change in the [[balance of terror]] can be seen as the complete embracement of the switch from the 1950s [[Eisenhower|Eisenhower doctrine]] of "[[massive retaliation]]"<ref>{{cite journal|first=Matthew|last=Jones|title=Targeting China: U.S. Nuclear Planning and 'Massive Retaliation' in East Asia, 1953–1955|journal=Journal of Cold War Studies|year=2008|volume=10|issue=4|pages=37–65|doi=10.1162/jcws.2008.10.4.37|s2cid=57564482}}</ref> to one of "[[flexible response]]", which has been growing in importance in the US nuclear war fighting plan/[[Single Integrated Operational Plan|SIOP]] every decade since.

For example, the United States adopted a policy in 1996 of allowing the targeting of its nuclear weapons at non-state actors ("[[terrorists]]") armed with [[weapons of mass destruction]].<ref>{{citation|author1=Daniel Plesch|author2=Stephen Young|title=Senseless policy|url=https://books.google.com/books?id=sgsAAAAAMBAJ|journal=[[Bulletin of the Atomic Scientists]]|year=1998|volume=54|issue=6|publisher=Educational Foundation for Nuclear Science, Inc.|page=4|doi=10.1080/00963402.1998.11456892|bibcode=1998BuAtS..54f...4P}}</ref>

Another dimension to the tactical use of nuclear weapons is that of such weapons deployed at sea for use against surface and submarine vessels. Until 1992, vessels of the [[United States Navy]] (and their aircraft) deployed various such weapons as bombs, rockets (guided and unguided), torpedoes, and depth charges. Such tactical naval nuclear weapons were considered more acceptable to use early in a conflict because there would be few civilian casualties. It was feared by many planners that such use would probably quickly have escalated into a large-scale nuclear war.<ref>{{cite web|title=Declassified: Nuclear Weapons at Sea, Conclusions and Recommendations|url=https://fas.org/blogs/security/2016/02/nuclear-weapons-at-sea/|website=Federation of American Scientists|access-date=2016-04-19}}</ref> This situation was particularly exacerbated by the fact that such weapons at sea were not constrained by the safeguards provided by the [[Permissive Action Link]] attached to U.S. Air Force and Army nuclear weapons. It is unknown if the navies of the other nuclear powers yet today deploy tactical nuclear weapons at sea.

The [[Nuclear Posture Review|2018 US Nuclear Posture Review]] emphasised the need for the US to have sub-strategic nuclear weapons as additional layers for its nuclear deterrence.<ref>{{cite web|title=2018 Nuclear Posture Review|url=https://www.defense.gov/News/SpecialReports/2018NuclearPostureReview.aspx|website=US Defense Department|access-date=2018-06-26}}</ref>

===Nuclear terrorism===
{{Main|Nuclear terrorism|Nuclear blackmail}}
[[Nuclear terrorism]] by non-state organizations or actors (even individuals) is a largely unknown and understudied factor in nuclear deterrence thinking, as states possessing nuclear weapons are susceptible to retaliation in kind, while sub- or trans-state actors may be less so. The collapse of the Soviet Union has given rise to the possibility that former Soviet nuclear weapons might become available on the [[black market]] (so-called 'loose nukes').

A number of other concerns have been expressed about the security of nuclear weapons in newer nuclear powers with relatively less stable governments, such as [[Pakistan]], but in each case, the fears have been addressed to some extent by statements and evidence provided by those nations, as well as cooperative programs between nations. Worry remains, however, in many circles that a relative decrease in the security of nuclear weapons has emerged in recent years, and that terrorists or others may attempt to exert control over (or use) nuclear weapons, militarily applicable technology, or nuclear materials and fuel.

Another possible nuclear terrorism threat are devices designed to disperse radioactive materials over a large area using conventional explosives, called [[dirty bomb]]s. The detonation of a "dirty bomb" would not cause a nuclear explosion, nor would it release enough radiation to kill or injure a large number of people. However, it could cause severe disruption and require potentially very costly decontamination procedures and increased spending on security measures.<ref>{{cite web|url=https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/dirty-bombs-bg.html|title=Backgrounder on Dirty Bombs|author=US Nuclear Regulatory Commission|date=May 2007|access-date=2010-04-26}}</ref>

Radioactive materials can also be used for targeted assassinations. For example, the [[Alexander Litvinenko poisoning|poisoning of Alexander Litvinenko]] was described by medical professionals, as "an ominous landmark: the beginning of an era of [[nuclear terrorism]]."<ref>"Ushering in the era of nuclear terrorism", by Patterson, Andrew J. MD, PhD, ''Critical Care Medicine'', v. 35, pp.&nbsp;953–954, 2007.</ref><ref>"Beyond the Dirty Bomb: Re-thinking Radiological Terror", by  James M. Acton;  M. Brooke Rogers; Peter D. Zimmerman, DOI: 10.1080/00396330701564760, ''Survival'', Volume 49, Issue 3 September 2007, pages 151–168</ref><ref>"The Litvinenko File: The Life and Death of a Russian Spy", by Martin Sixsmith, True Crime, 2007 ISBN 0-312-37668-5, page 14.</ref><ref name="Bellona">[https://bellona.org/news/nuclear-issues/radioactive-waste-and-spent-nuclear-fuel/2006-12-radiological-terrorism-soft-killers Radiological Terrorism: “Soft Killers”] by Morten Bremer Mærli, [[Bellona Foundation]]</ref>

===Alternative conflict resolution===
{{Main|Conflict resolution}}
Alternatives to nuclear warfare include [[Deterrence theory#Nuclear deterrence theory|nuclear deterrence]],<ref name="s977">{{cite journal | last=Hoey | first=Fintan | title=Japan and Extended Nuclear Deterrence: Security and Non-proliferation | journal=Journal of Strategic Studies | volume=39 | issue=4 | date=6 June 2016 | issn=0140-2390 | doi=10.1080/01402390.2016.1168010 | pages=484–501}}</ref> [[nuclear disarmament]] and [[Treaty on the Non-Proliferation of Nuclear Weapons]].

==History==
{{Main|History of nuclear weapons|Timeline of nuclear weapons development}}

===1940s===
====Atomic bombings of Hiroshima and Nagasaki====
{{Main|Atomic bombings of Hiroshima and Nagasaki}}[[Image:Nagasakibomb.jpg|thumb|Mushroom cloud from the atomic explosion over Nagasaki rising {{convert|18000|m|ft|abbr=on}} into the air on the morning of August 9, 1945]]

During the final stages of [[World War II]] in 1945, the United States conducted atomic raids on the Japanese cities of [[Hiroshima]] and [[Nagasaki]], the first on August 6, 1945, and the second on August 9, 1945. These two events were the only times nuclear weapons have been used in [[combat]].<ref>{{Cite book| last = Hakim| first = Joy| title = A History of Us: War, Peace and all that Jazz| publisher=Oxford University Press| year = 1995| location = New York| isbn = 0-19-509514-6 }}</ref>

For six months before the atomic bombings, the U.S. [[Twentieth Air Force|20th Air Force]] under [[General (United States)|General]] [[Curtis LeMay]] executed low-level [[Firebombing|incendiary raids]] [[Air raids on Japan|against Japanese cities]]. The most destructive air raid to occur during the process was not the nuclear attacks, but the [[Bombing of Tokyo|''Operation Meetinghouse'' raid on Tokyo]]. On the night of March 9–10, 1945, ''Operation Meetinghouse'' commenced and 334 [[Boeing B-29 Superfortress]] [[bomber]]s took off to raid, with 279 of them dropping 1,665 tons of [[incendiary bombs|incendiaries]] and [[explosive]]s on [[Tokyo]]. The bombing was meant to burn wooden buildings and indeed the bombing caused fire that created a 50&nbsp;m/s wind, which is comparable to tornadoes. Each bomber carried 6 tons of bombs. A total of 381,300 bombs, which amount to 1,783 tons of bombs, were used in the bombing. Within a few hours of the raid, it had killed an estimated 100,000 people and destroyed {{convert|41|km2|sqmi|abbr=on}} of the city and 267,000 buildings in a single night — the deadliest bombing raid in [[military aviation]] history other than the atomic raids on Hiroshima and Nagasaki.<ref>{{cite web|url=http://www.commondreams.org/headlines05/0310-08.htm|title=1945 Tokyo Firebombing Left Legacy of Terror, Pain|work=Common Dreams|access-date=2014-12-08|archive-date=2015-01-03|archive-url=https://web.archive.org/web/20150103023353/http://www.commondreams.org/headlines05/0310-08.htm|url-status=dead}}</ref><ref>{{cite magazine |url=https://www.wired.com/2011/03/0309incendiary-bombs-kill-100000-tokyo/ |title=March 9, 1945: Burning the Heart Out of the Enemy |author=<!--Staff writer(s); no by-line.--> |date=9 March 2011 |magazine=Wired |publisher=Condé Nast Digital |access-date=June 8, 2014}}</ref><ref>Wolk (2010), p. 125</ref><ref>{{cite web|url=http://www.history.com/this-day-in-history/firebombing-of-tokyo|title=Firebombing of Tokyo|work=HISTORY.com}}</ref> By early August 1945, an estimated 450,000 people had died as the U.S. had intensely firebombed a total of 67 Japanese cities.

In late June 1945, as the U.S. wrapped up the two-and-a-half-month [[Battle of Okinawa]] (which cost the lives of 260,000 people, including 150,000 civilians),<ref>{{cite web |url=http://www-cgsc.army.mil/carl/resources/csi/Huber/Huber.asp |title=Japan's Battle of Okinawa, March–June 1945|publisher=[[Command and General Staff College]] |access-date=2016-12-13 |url-status=dead |archive-url=https://web.archive.org/web/20090214183638/http://www-cgsc.army.mil/carl/resources/csi/Huber/Huber.asp |archive-date=February 14, 2009 }}</ref><ref>{{cite book |title=Ways of Forgetting, Ways of Remembering: Japan in the Modern World |pages=273 |date=February 4, 2014 |publisher=New Press}}</ref> it was faced with the prospect of invading the [[Japanese archipelago|Japanese home islands]] in an operation codenamed [[Operation Downfall]]. Based on the U.S. casualties from the preceding [[Leapfrogging (strategy)|island-hopping campaigns]], American commanders estimated that between 50,000 and 500,000 U.S. troops would die and at least 600,000–1,000,000 others would be injured while invading the Japanese home islands. The U.S. manufacture of 500,000 [[Purple Heart]]s from the anticipated high level of casualties during the U.S. invasion of Japan gave a demonstration of how deadly and costly it would be. [[President of the United States|President]] [[Harry S. Truman]] realized he could not afford such a horrendous casualty rate, especially since over 400,000 American combatants had already died fighting in both the [[European theatre of World War II|European]] and the [[Pacific War|Pacific theaters]] of the war.<ref>{{cite web |url=http://cgsc.cdmhost.com/cdm4/document.php?CISOROOT=/p4013coll8&CISOPTR=130&REC=2 |title=United States Dept. of the Army, Army Battle Casualties and Non-Battle Deaths in World War II |publisher=Cgsc.cdmhost.com |access-date=2011-06-15 |archive-date=2010-05-12 |archive-url=https://web.archive.org/web/20100512130416/http://cgsc.cdmhost.com/cdm4/document.php?CISOROOT=%2Fp4013coll8&CISOPTR=130&REC=2 |url-status=dead }}</ref>

On July 26, 1945, the United States, the [[United Kingdom]], and the [[Republic of China (1912–1949)|Republic of China]] issued a [[Potsdam Declaration]] that called for the [[unconditional surrender]] of Japan. It stated that if Japan did not surrender, it would face "prompt and utter destruction".<ref name=atomicarchive>{{cite web | title = Potsdam Declaration: Proclamation Defining Terms for Japanese Surrender Issued, at Potsdam, July 26, 1945 | url = http://www.atomicarchive.com/Docs/Hiroshima/Potsdam.shtml | publisher = National Science Digital Library }}</ref><ref>{{cite web | publisher = United States Department of State, Office of the Historian | url = https://history.state.gov/milestones/1937-1945/PotsdamConf | title = Milestones: 1937–1945 / The Potsdam Conference, 1945 | url-status = dead | archive-url = https://web.archive.org/web/20131029194738/http://history.state.gov/milestones/1937-1945/PotsdamConf | archive-date = 2013-10-29 }}</ref> The Japanese government [[mokusatsu|ignored]] this ultimatum, sending a message that they were not going to surrender. In response to the rejection, President Truman authorized the dropping of the atomic bombs. At the time of its use, there were only two atomic bombs available, and despite the fact that more were in production back in [[Contiguous United States|mainland U.S.]], the third bomb wouldn't be available for combat until September.<ref>{{cite book|last1=Newman|first1=Robert P.|title=Truman and the Hiroshima Cult|date=1995|page=86|url=https://books.google.com/books?id=Haf2g1mbsH8C|isbn=978-0-87013-940-6|publisher=MSU Press}}</ref><ref name="Generals">{{cite web |title=The Atomic Bomb and the End of World War II, A Collection of Primary Sources| publisher=[[George Washington University]]| date=August 13, 1945| work=National Security Archive Electronic Briefing Book No. 162 | url=http://www.gwu.edu/~nsarchiv/NSAEBB/NSAEBB162/72.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.gwu.edu/~nsarchiv/NSAEBB/NSAEBB162/72.pdf |archive-date=2022-10-09 |url-status=live}}</ref>

[[File:Sumiteru Taniguchi back.jpg|thumb|A photograph of [[Sumiteru Taniguchi]]'s back injuries taken in January 1946 by a U.S. Marine photographer]]
[[File:Hypocenter_of_Atomic_bombings_in_Nagasaki.jpg|265x265px|right|thumb|[[Hypocenter]] of Atomic bomb in Nagasaki]]
On August 6, 1945, the uranium-type nuclear weapon codenamed "[[Little Boy]]" was detonated over the Japanese city of [[Hiroshima]] with an energy of about {{convert|15|ktonTNT|GJ|abbr=off}}, destroying nearly 50,000 buildings (including the [[headquarters]] of the [[Second General Army (Japan)|2nd General Army]] and [[5th Division (Imperial Japanese Army)|Fifth Division]]) and killing approximately 70,000 people, including 20,000 Japanese combatants and 20,000 Korean slave laborers.<ref name=eyewitness>Adams, S. & Crawford, A.. 2000. ''World War II.'' First edition. Printed in association with the Imperial War Museum. Eyewitness Books series. New York, Doring Kindersley Limited</ref><ref>{{cite book |title=The Real History of World War II: A New Look at the Past |url=https://archive.org/details/realhistoryofwor00axel |url-access=registration |author=Alan Axelrod |publisher=Sterling |page=[https://archive.org/details/realhistoryofwor00axel/page/350 350] |date=May 6, 2008|isbn=9781402740909 }}</ref> Three days later, on August 9, a plutonium-type nuclear weapon codenamed "[[Fat Man]]" was used against the Japanese city of Nagasaki, with the explosion equivalent to about {{convert|20|ktonTNT|GJ|abbr=off}}, destroying 60% of the city and killing approximately 35,000 people, including 23,200–28,200 Japanese munitions workers, 2,000 Korean slave laborers, and 150 Japanese combatants.<ref>{{cite book |title=Nuke-Rebuke: Writers & Artists Against Nuclear Energy & Weapons (The Contemporary anthology series) |pages=22–29 |date=May 1, 1984 |publisher=The Spirit That Moves Us Press}}</ref> The industrial damage in Nagasaki was high, partly owing to the inadvertent targeting of the industrial zone, leaving 68–80 percent of the non-dock industrial production destroyed.<ref>{{cite book |title=Welcome To Planet Earth – 2050 – Population Zero |author= Robert Hull |date=October 11, 2011 |page=215 |publisher=[[AuthorHouse]] |isbn=978-1-4634-2604-0}}</ref> The U.S., despite not having a third device ready to be dropped, gave Japan one last warning that there would be another bombing if they did not surrender, and the target would be [[Tokyo]].

Six days after the detonation over Nagasaki, Japan announced [[Surrender of Japan|its surrender]] to the [[Allies of World War II|Allied Powers]] on August 15, 1945, signing the [[Japanese Instrument of Surrender|Instrument of Surrender]] on September 2, 1945, officially ending the [[Pacific War]] and, therefore, World War II, as [[Nazi Germany|Germany]] had already signed its [[German Instrument of Surrender|Instrument of Surrender]] on May 8, 1945, ending the [[European Theatre of World War II|war in Europe]]. The two atomic bombings led, in part, to [[Post-Occupation Japan|post-war Japan's]] adopting of the [[Three Non-Nuclear Principles]], which forbade the nation from developing nuclear armaments.<ref>{{cite web| last = Koizumi | first = Junichiro | author-link = Junichiro Koizumi | title = Address by Prime Minister Junichiro Koizumi at the Hiroshima Memorial Service for the Hiroshima Peace Memorial Ceremony | publisher=Prime Minister of Japan and His Cabinet | date = August 6, 2005 | url = http://www.kantei.go.jp/foreign/koizumispeech/2005/08/06aisatu_e.html | access-date = Nov 28, 2007 }}</ref>

====Immediately after the Japan bombings====
After the successful [[Trinity (nuclear test)|Trinity nuclear test]] July 16, 1945, which was the very first nuclear detonation, the [[Manhattan Project]] lead manager [[J. Robert Oppenheimer]] recalled:
{{blockquote|We knew the world would not be the same. A few people laughed, a few people cried, and most people were silent. I remembered the line from the [[Hinduism|Hindu]] scripture the ''[[Bhagavad Gita]]''. [[Vishnu]] is trying to persuade the prince that he should do his duty and to impress him takes on his multiarmed form and says, "Now, I am become Death, the destroyer of worlds." I suppose we all thought that one way or another.|[[J. Robert Oppenheimer]]|''The Decision To Drop The Bomb''<ref>{{cite journal|title=Oppenheimer's Ghost |date=November–December 2007|first=Jason |last=Pontin |journal=[[Technology Review]]}}</ref>|source=}}

[[Image:Oppenheimer (cropped).jpg|thumb|right|[[J. Robert Oppenheimer]]]]

[[Atomic Age|Immediately after]] the atomic bombings of Japan, the status of atomic weapons in international and military relations was unclear. Presumably, the United States hoped atomic weapons could offset the Soviet Union's larger conventional ground forces in [[Eastern Europe]], and possibly be used to pressure Soviet leader [[Joseph Stalin]] into making concessions. Under Stalin, the Soviet Union pursued its own atomic capabilities through a combination of scientific research and [[espionage]] directed against the American program. The Soviets believed that the Americans, with their limited nuclear arsenal, were unlikely to engage in any new world wars, while the Americans were not confident they could prevent a Soviet takeover of Europe, despite their atomic advantage.

Within the United States, the authority to produce and develop nuclear weapons was removed from military control and put instead under the civilian control of the [[United States Atomic Energy Commission]]. This decision reflected an understanding that nuclear weapons had unique risks and benefits that were separate from other military technology known at the time.

[[Image:Convair B-36 Peacemaker.jpg|thumb|right|[[Convair B-36]] bomber]]

For several years after [[World War II]], the United States 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 United States. It deployed atomic bombs around the world for potential use in conflicts. Over a period of a few years, many in the American 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.

Many proposals were suggested to put all American nuclear weapons under international control (by the newly formed [[United Nations]], for example) as an effort to deter both their usage and a [[nuclear arms race]]. However, no terms could be arrived at that would be agreed upon by both the United States and the Soviet Union.<ref>{{Cite web |last=United |first=Nations |title=International Day for the Total Elimination of Nuclear Weapons |url=https://www.un.org/en/observances/nuclear-weapons-elimination-day |access-date=2024-02-13 |website=United Nations |language=en}}</ref>{{citation needed|date=June 2020}}

[[Image:US and USSR nuclear stockpiles.svg|thumb|right|American and Soviet/Russian nuclear stockpiles]]

On August 29, 1949, the [[Soviet Union]] tested its [[RDS-1|first nuclear weapon]] at [[Semipalatinsk Test Site|Semipalatinsk]] in [[Kazakhstan]] (see also [[Soviet atomic bomb project]]). Scientists in the United States from the Manhattan Project had warned that, in time, the Soviet Union would certainly develop nuclear capabilities of its own. Nevertheless, the effect upon military thinking and planning in the United States was dramatic, primarily because American military strategists had not anticipated the Soviets would "catch up" so soon. However, at this time, they had not discovered that the Soviets had conducted significant [[nuclear espionage]] of the project from spies at [[Los Alamos National Laboratory]], the most significant of which was done by the theoretical physicist [[Klaus Fuchs]].{{citation needed|date=April 2015}} The first Soviet bomb was more or less a deliberate copy of the [[Fat Man]] [[plutonium]] device. In the same year the first US-Soviet nuclear war plan was penned in the US with [[Operation Dropshot]].

With the monopoly over nuclear technology broken, worldwide nuclear proliferation accelerated. The [[United Kingdom]] tested its [[Operation Hurricane|first independent atomic bomb]] in 1952, followed by [[France]] developing its [[Gerboise Bleue (nuclear test)|first atomic bomb]] in 1960 and then [[China]] developing its [[Project 596|first atomic bomb]] in 1964. While much smaller than the arsenals of the United States and the Soviet Union, [[Western Europe]]'s nuclear reserves were nevertheless a significant factor in strategic planning during the [[Cold War]]. A top-secret [[White paper]], compiled by the [[Royal Air Force]] and produced for the British Government in 1959, estimated that [[V bomber|British V bombers]] carrying nuclear weapons were capable of destroying key cities and military targets in the Soviet Union, with an estimated 16&nbsp;million deaths in the Soviet Union (half of whom were estimated to be killed on impact and the rest fatally injured) ''before'' bomber aircraft from the [[Strategic Air Command|U.S. Strategic Air Command]] reached their targets.

===1950s===
[[File:USAF Atomic Bomb Delivery Aircraft 1950s Film.webm|thumb|''"USAF Atomic Bomb Delivery Aircraft"'' (1952).]]
Although the Soviet Union had nuclear weapon capabilities at the beginning of the [[Cold War]], the United States still had an advantage in terms of bombers and weapons. In any exchange of hostilities, the United States would have been capable of bombing the Soviet Union, whereas the Soviet Union would have more difficulty carrying out the reverse mission.

The widespread introduction of [[Jet engine|jet]]-powered [[interceptor aircraft]] upset this imbalance somewhat by reducing the effectiveness of the American bomber fleet. In 1949 [[Curtis LeMay]] was placed in command of the Strategic Air Command and instituted a program to update the bomber fleet to one that was all-jet. During the early 1950s the [[Boeing B-47 Stratojet|B-47 Stratojet]] and [[Boeing B-52 Stratofortress|B-52 Stratofortress]] were introduced, providing the ability to bomb the Soviet Union more easily. Before the development of a capable strategic missile force in the Soviet Union, much of the war-fighting doctrine held by western nations revolved around using a large number of smaller nuclear weapons in a tactical role. It is debatable whether such use could be considered "limited" however because it was believed that the United States would use its own strategic weapons (mainly bombers at the time) should the Soviet Union deploy any kind of nuclear weapon against civilian targets. [[Douglas MacArthur]], an American general, was fired by President [[Harry Truman]], partially because he persistently requested permission to use his own discretion in deciding whether to utilize atomic weapons on the [[People's Republic of China]] in 1951 during the [[Korean War]].<ref>{{Cite web|url=http://www.nti.org/e_research/profiles/China/Nuclear/5630.html|archiveurl=https://web.archive.org/web/20081015161227/http://www.nti.org/e_research/profiles/China/Nuclear/5630.html|url-status=dead|title=Nuclear Chronology 1945–1959|archivedate=October 15, 2008}}</ref> [[Mao Zedong]], China's communist leader, gave the impression that he would welcome a nuclear war with the capitalists because it would annihilate what he viewed as their imperialist system.<ref name="auto">"[https://web.archive.org/web/20110629001410/http://www.time.com/time/magazine/article/0,9171,946612-2,00.html Instant Wisdom: Beyond the Little Red Book]". TIME. September 20, 1976.</ref><ref>[[Robert Service (historian)|Robert Service]]. [https://books.google.com/books?id=Frgm5QodnFoC&pg=PA321 ''Comrades!: A History of World Communism.''] [[Harvard University Press]], 2007. p. 321. {{ISBN|0-674-02530-X}}</ref>

{{blockquote|Let us imagine how many people would die if war breaks out. There are 2.7 billion people in the world, and a third could be lost. If it is a little higher it could be half ... I say that if the worst came to the worst and one-half dies, there will still be one-half left, but imperialism would be razed to the ground and the whole world would become socialist. After a few years there would be 2.7 billion people again.| Mao Zedong, 1957<ref>Dikötter, Frank. ''[[Mao's Great Famine]]: The History of China's Most Devastating Catastrophe, 1958–62.'' Walker & Company, 2010. p.13. {{ISBN|0-8027-7768-6}}</ref>}}

[[File:Exercise Desert Rock I (Buster-Jangle Dog) 002.jpg|right|thumb|The U.S. and USSR conducted hundreds of [[Nuclear testing|nuclear tests]], including the [[Desert Rock exercises]] at the [[Nevada Test Site]], USA, pictured above during the [[Korean War]] to familiarize their soldiers with conducting operations and counter-measures around nuclear detonations, as the Korean War threatened to expand.]]

The concept of a "Fortress North America" emerged during the Second World War and persisted into the Cold War to refer to the option of defending [[Canada]] and the United States against their enemies if the rest of the world were lost to them. This option was rejected with the formation of [[NATO]] and the decision to permanently station troops in Europe.

In the summer of 1951, [[Project Vista]] started, in which project analysts such as [[Robert F. Christy]] looked at how to defend Western Europe from a Soviet invasion. The emerging development of [[tactical nuclear weapons]] was looked upon as a means to give Western forces a qualitative advantage over the Soviet numerical supremacy in conventional weapons.<ref>{{cite web| url = http://www.patrickmccray.com/wp/wp-content/uploads/2012/12/2004-McCray-Vista-Paper.pdf| title = Project Vista, Caltech, and the dilemmas of Lee DuBridge| access-date = 2014-10-07| archive-date = 2017-09-03| archive-url = https://web.archive.org/web/20170903225132/http://www.patrickmccray.com/wp/wp-content/uploads/2012/12/2004-McCray-Vista-Paper.pdf| url-status = dead}}</ref>

Several scares about the increasing ability of the Soviet Union's strategic bomber forces surfaced during the 1950s. The defensive response by the United States was to deploy a fairly strong "layered defense" consisting of [[interceptor aircraft]] and [[Surface-to-air missile|anti-aircraft missile]]s, like the [[Project Nike|Nike]], and guns, like the [[M51 Skysweeper]], near larger cities. However, this was a small response compared to the construction of a huge fleet of nuclear bombers. The principal [[nuclear strategy]] was to massively penetrate the Soviet Union. Because such a large area could not be defended against this overwhelming attack in any credible way, the Soviet Union would lose any exchange.

This logic became ingrained in American nuclear doctrine and persisted for much of the duration of the [[Cold War]]. As long as the strategic American nuclear forces could overwhelm their Soviet counterparts, a Soviet pre-emptive strike could be averted. Moreover, the Soviet Union could not afford to build any reasonable counterforce, as the economic output of the United States was far larger than that of the Soviets, and they would be unable to achieve "nuclear parity".

Soviet nuclear doctrine, however, did not match American nuclear doctrine.<ref name="kms1.isn.ethz.ch">{{Cite web |url=http://kms1.isn.ethz.ch/serviceengine/Files/ISN/46280/ipublicationdocument_singledocument/14933a8e-14e8-43d7-a257-6bdab65dba50/en/ZB79_000.pdf |title=Military Planning for European Theatre Conflict During the Cold War |access-date=2011-10-24 |archive-url=https://web.archive.org/web/20120402212438/http://kms1.isn.ethz.ch/serviceengine/Files/ISN/46280/ipublicationdocument_singledocument/14933a8e-14e8-43d7-a257-6bdab65dba50/en/ZB79_000.pdf |archive-date=2012-04-02 |url-status=dead }}</ref><ref>{{cite web|url=http://www.airpower.au.af.mil/airchronicles/aureview/1979/mar-apr/jenson.html|title=Nuclear Strategy differences in Soviet and American thinking|access-date=2012-06-07|archive-date=2017-01-26|archive-url=https://web.archive.org/web/20170126002842/http://www.airpower.au.af.mil/airchronicles/aureview/1979/mar-apr/jenson.html|url-status=dead}}</ref> Soviet military planners assumed they could win a nuclear war.<ref name="kms1.isn.ethz.ch"/><ref>[https://www.scribd.com/doc/63015546/Why-Russia-Thinks-It-Could-Fight-and-Win-a-Nuclear-War Why the Soviet Union thinks it can fight and win a Nuclear War], Richard Pipes, Professor of History Harvard University 1977</ref><ref name="gwu.edu">{{Cite web|url=https://nsarchive2.gwu.edu/nukevault/ebb285/|title=Candid Interviews with Former Soviet Officials Reveal U.S. Strategic Intelligence Failure Over Decades|website=nsarchive2.gwu.edu}}</ref> Therefore, they ''expected'' a large-scale nuclear exchange, followed by a "conventional war" which itself would involve heavy use of [[tactical nuclear weapon]]s. American doctrine rather assumed that Soviet doctrine was similar, with the ''mutual'' in [[mutually assured destruction]] necessarily requiring that the other side see things in much the same way, rather than believing—as the Soviets did—that they could fight a large-scale, "combined nuclear and conventional" war.

In accordance with their doctrine, the Soviet Union conducted [[Totskoye nuclear test|large-scale military exercises]] to explore the possibility of defensive and offensive [[warfare]] during a [[nuclear war]]. The exercise, under the code name of "[[Totskoye nuclear exercise|Snowball]]", involved the detonation of a nuclear bomb about twice as powerful as that which fell on [[Atomic bombings of Hiroshima and Nagasaki|Nagasaki]] and an army of approximately 45,000 soldiers on [[maneuvers]] through the [[hypocenter]] immediately after the blast.<ref>[[Viktor Suvorov]], ''[http://militera.lib.ru/research/suvorov7/index.html Shadow of Victory]'' ({{lang|ru|Тень победы}}), Donetsk, 2003, {{ISBN|966-696-022-2}}, pages 353–375.</ref> The exercise was conducted on September 14, 1954, under command of [[Marshal of the Soviet Union|Marshal]] [[Georgy Zhukov]] to the north of [[Totskoye]] village in [[Orenburg Oblast]], [[Russia]].

[[File:The Atom Soldier - The Big Picture.webm|thumb|''"The Atom Soldier - The Big Picture"'' Camp Desert Rock military exercise information film reel.]]
A revolution in nuclear strategic thought occurred with the introduction of the [[intercontinental ballistic missile]] (ICBM), which the Soviet Union first successfully tested in August 1957. In order to deliver a warhead to a target, a missile was much faster and more cost-effective than a bomber, and enjoyed a higher survivability due to the enormous difficulty of interception of the ICBMs (due to their high altitude and extreme speed). The Soviet Union could now afford to achieve nuclear parity with the United States in raw numbers, although for a time, they appeared to have chosen not to.

Photos of Soviet missile sites set off a wave of panic in the U.S. military, something the launch of [[Sputnik]] would do for the American public a few months later. Politicians, notably then-[[United States Senate|U.S. Senator]] [[John Fitzgerald Kennedy|John F. Kennedy]] suggested that a "[[missile gap]]" existed between the Soviet Union and the United States.<!--This was a savvy political ploy, as the US administration almost certainly knew better, and also knew that they could not be corrected without violating military security. It should be pointed out, though, that Dwight D. Eisenhower's own [[Gaither Report|Gaither panel]] had also overestimated Soviet nuclear capabilities in their 1957 report.[http://www.politicalreviewnet.com/polrev/reviews/DIPH/R_0145_2096_014_19322.asp][http://globetrotter.berkeley.edu/people/York/york88-con4.html] One result of this, however, was that the Soviets ''believed'' the vulnerability actually existed, with resulting temptation; luckily, cooler heads prevailed. After Kennedy won the 1960 Presidential election, the "missile gap" (conveniently) went away.--><!--This political interpretation needs to be attributed or made neutral.--> The US military gave missile development programs the highest national priority, and several [[reconnaissance aircraft|spy aircraft]] and [[reconnaissance satellite]]s were designed and deployed to observe Soviet progress.

Early ICBMs and bombers were relatively inaccurate, which led to the concept of [[countervalue]] strikes — attacks directly on the enemy population, which would theoretically lead to a collapse of the enemy's will to fight. During the Cold War, the Soviet Union invested in extensive protected civilian infrastructure, such as large "nuclear-proof" bunkers and non-perishable food stores. By comparison, smaller scale [[civil defense]] programs were instituted in the United States starting in the 1950s, where schools and other public buildings had basements stocked with non-perishable food supplies, canned water, first aid, and [[dosimeter]] and [[Geiger counter]] radiation-measuring devices. Many of the locations were given "[[fallout shelter]]" designation signs. [[CONELRAD]] radio information systems were adopted, whereby the commercial radio sector (later supplemented by the [[National Emergency Alarm Repeater]]s) would broadcast on two [[AM broadcasting|AM radio]] frequencies in the event of a Civil Defense (CD) emergency. These two frequencies, 640 and 1240&nbsp;kHz, were marked with small CD triangles on the tuning dial of radios of the period, as can still be seen on 1950s-vintage radios on online auction sites and museums. A few backyard [[fallout shelter]]s were built by private individuals.

[[Henry Kissinger]]'s view on tactical nuclear war in his controversial 1957 book ''Nuclear Weapons and Foreign Policy'' was that any nuclear weapon exploded in [[air burst]] mode that was below 500 kilotons in yield and thus averting serious fallout, may be more decisive and less costly in human lives than a protracted conventional war.

A list of targets made by the United States was released sometime during December 2015 by the U.S. [[National Archives and Records Administration]]. The language used to describe targets is "designated ground zeros". The list was released after a request was made during 2006 by William Burr who belongs to a research group at [[George Washington University]], and belongs to a previously [[Classified information#Secret|top-secret]] 800-page document. The list is entitled "Atomic Weapons Requirements Study for 1959" and was produced by U.S. [[Strategic Air Command]] during the year 1956.<ref>S. Shane – [https://www.msn.com/en-gb/news/us/1950s-us-nuclear-target-list-offers-chilling-insight/ar-BBnQleB?li=AAaeUIW 1950s U.S. Nuclear Target List Offers Chilling Insight], ''[[The New York Times]]'', Retrieved 2015-12-23</ref>

===1960s===
[[File:Jupiter on its launch pad.jpg|thumb|More than 100 US-built missiles having the capability to strike Moscow with nuclear warheads were [[PGM-19 Jupiter#Military deployment|deployed in Italy and Turkey]] in 1961]]
[[Image:Cuban missiles.jpg|thumb|right|[[F-101 Voodoo|RF-101 Voodoo]] reconnaissance photograph of the [[MRBM]] launch site in [[San Cristóbal, Cuba]] (1962)]]

In 1960, the United States developed its first [[Single Integrated Operational Plan]], a range of targeting options, and described launch procedures and target sets against which nuclear weapons would be launched, variants of which were in use from 1961 to 2003. That year also saw the start of the [[Missile Defense Alarm System]], an American system of 12 early-warning satellites that provided limited notice of Soviet intercontinental ballistic missile launches between 1960 and 1966. The [[Ballistic Missile Early Warning System]] was completed in 1964.

The most powerful atomic bomb ever made, the Tsar Bomba, was tested by the Soviets on October 30, 1961. It was 50 megatons, or equal to 50 million tons of regular explosives.<ref>{{Cite news|last=Broad|first=William J.|date=2021-10-30|title=When the Soviets Set Off the Biggest Nuclear Bomb, J.F.K. Didn't Flinch|language=en-US|work=The New York Times|url=https://www.nytimes.com/2021/10/30/science/tsar-bomba-60.html|access-date=2021-12-17|issn=0362-4331}}</ref> A complex and worrisome situation developed in 1962, in what is called the [[Cuban Missile Crisis]]. The Soviet Union placed medium-range ballistic missiles {{convert|90|mi|km}} from the United States, possibly as a direct response to American [[Jupiter missile]]s placed in [[Turkey]]. After intense negotiations, the Soviets ended up removing the missiles from Cuba and decided to institute a massive weapons-building program of their own. In exchange, the United States dismantled its launch sites in Turkey, although this was done secretly and not publicly revealed for over two decades. First Secretary [[Nikita Khrushchev]] did not even reveal this part of the agreement when he came under fire by political opponents for mishandling the crisis. Communication delays during the crisis led to the establishment of the [[Moscow–Washington hotline]] to allow reliable, direct communications between the two nuclear powers.

By the late 1960s, the number of ICBMs and warheads was so high on both sides that it was believed that both the United States and the Soviet Union were capable of completely destroying the infrastructure and a large proportion of the population of the other country. Thus, by some western [[game theorist]]s, a [[balance of power in international relations|balance of power]] system known as [[mutually assured destruction]] (or ''MAD'') came into being. It was thought that no full-scale exchange between the powers would result in an outright winner, with at best one side emerging the [[pyrrhic victory|pyrrhic victor]]. Thus both sides were [[stability-instability paradox|deterred]] from risking the initiation of a direct confrontation, instead being forced to engage in lower-intensity [[proxy wars]].

During this decade the [[People's Republic of China]] began to build subterranean infrastructure such as the [[Underground Project 131]] following the [[Sino-Soviet split]].

<!--these next two paragraphs should be elsewhere in the text, not in "1960s"-->
One drawback of the MAD doctrine was the possibility of a nuclear war occurring without either side intentionally striking first. [[Early Warning System]]s (EWS) were notoriously error-prone. For example, on 78 occasions in 1979 alone, a "missile display conference" was called to evaluate detections that were "potentially threatening to the North American continent". Some of these were trivial errors and were spotted quickly, but several went to more serious levels. On September 26, 1983, [[Stanislav Petrov]] received convincing indications of an American first strike launch against the Soviet Union, but positively identified the warning as a false alarm. Though it is unclear what role Petrov's actions played in preventing a nuclear war during this incident, he has been honored by the United Nations for his actions.

Similar incidents happened many times in the United States, due to failed [[Integrated circuit|computer chips]],<ref>[http://www.wagingpeace.org/articles/1998/01/00_phillips_20-mishaps.htm June 80: Faulty Computer Chip] {{webarchive|url=https://web.archive.org/web/20131226153334/http://www.wagingpeace.org/articles/1998/01/00_phillips_20-mishaps.htm |date=2013-12-26 }}, ''20 Mishaps that Might Have Started Accidental Nuclear War'', by Alan F. Phillips, M.D., January 1998, Nuclear Age Peace Foundation</ref> misidentifications of large flights of geese, test programs, and bureaucratic failures to notify early warning military personnel of legitimate launches of test or weather missiles. For many years, the [[United States Air Force|U.S. Air Force]]'s strategic bombers were kept airborne on a daily rotating basis "around the clock" (see [[Operation Chrome Dome]]), until the number and severity of [[List of military nuclear accidents|accidents]], the [[1968 Thule Air Base B-52 crash]] in particular,<ref>{{cite news |title=The Cold War's Missing Atom Bombs |url=https://www.spiegel.de/international/world/a-nuclear-needle-in-a-haystack-the-cold-war-s-missing-atom-bombs-a-590513.html |work=Der Spiegel |date=14 November 2008}}</ref> persuaded policymakers it was not worthwhile.

===1970s===
Israel responded to the Arab [[Yom Kippur War]] attack on 6 October 1973 by assembling 13 nuclear weapons in a tunnel under the [[Negev desert]] when Syrian tanks were sweeping in across the [[Golan Heights]]. On 8 October 1973, Israeli Prime Minister [[Golda Meir]] authorized Defense Minister [[Moshe Dayan]] to activate the 13 Israeli nuclear warheads and distribute them to [[Israeli air force]] units, with the intent that they be used if Israel began to be overrun.<ref>Seymour M. Hersh, ''The Samson Option: Israel's Nuclear Arsenal and American Foreign Policy'' (Random House, 1991) p.&nbsp;225.</ref>

On 24 October 1973, as US President [[Richard Nixon]] was preoccupied with the [[Watergate scandal]], Henry Kissinger ordered a [[DEFCON]]-3 alert{{dubious|date=August 2021}} preparing American B-52 nuclear bombers for war. Intelligence reports indicated that the USSR was preparing to defend Egypt in its [[Yom Kippur War]] with Israel. It had become apparent that if Israel had dropped nuclear weapons on Egypt or Syria, as it prepared to do, then the USSR would have retaliated against Israel, with the US then committed to providing Israeli assistance, possibly escalating to a general nuclear war.<ref name="ReferenceB">Nuclear Weapons in the Cold War, Bernard Brodie</ref>

By the late 1970s, people in both the [[United States]] and the [[Soviet Union]], along with the rest of the world, had been living with the concept of [[mutual assured destruction]] (MAD) for about a decade, and it became deeply ingrained into the psyche and popular culture of those countries.<ref>{{Cite web |title=The threats of nuclear warfare as depicted in the popular culture of the 1960s {{!}} Britannica |url=https://www.britannica.com/video/186541/overview-atomic-bomb-Strangelove-threat-warfare-missile |access-date=2024-06-14 |website=www.britannica.com |language=en}}</ref>

On May 18, 1974, [[India]] conducted its first nuclear test in the [[Pokhran]] test range. The name of the operation was [[Smiling Buddha]], and India termed the test as a "[[peaceful nuclear explosion]]."

The Soviet [[Duga radar|Duga]] early warning [[over-the-horizon radar]] system was made operational in 1976. The extremely powerful radio transmissions needed for such a system led to much disruption of civilian shortwave broadcasts, earning it the nickname "[[Russian Woodpecker]]".

The idea that any nuclear conflict would eventually escalate was a challenge for military strategists. This challenge was particularly severe for the United States and its [[NATO]] allies. It was believed (until the 1970s) that a Soviet tank offensive into Western Europe would quickly overwhelm NATO conventional forces, leading to the necessity of the West escalating to the use of tactical nuclear weapons, one of which was the [[W-70]].

This strategy had one major (and possibly critical) flaw, which was soon realized by military analysts but highly underplayed by the U.S. military: conventional [[NATO]] forces in the European theatre of war were far outnumbered by similar Soviet and [[Warsaw Pact]] forces, and it was assumed that in case of a major Soviet attack (commonly envisioned as the "Red tanks rolling towards the [[North Sea]]" scenario) that NATO—in the face of quick conventional defeat—would soon have no other choice but to resort to tactical nuclear strikes against these forces. Most analysts agreed that once the first nuclear exchange had occurred, escalation to global nuclear war would likely become inevitable. The [[Warsaw Pact]]'s vision of an atomic war between NATO and Warsaw Pact forces was simulated in the top-secret exercise [[Seven Days to the River Rhine]] in 1979. The British government exercised their vision of a Soviet nuclear attack with [[Square Leg]] in early 1980.

Large hardened nuclear [[weapon storage area]]s were built across European countries in anticipation of local US and European forces falling back as the conventional NATO defense from the Soviet Union, named [[REFORGER]], was believed to only be capable of stalling the Soviets for a short time.

===1980s===
[[Image:Trident C-4 montage.jpg|right|thumb|Montage of the launch of a [[Trident missile|Trident C4]] [[SLBM]] and the paths of its reentry vehicles]]
[[File:US nuclear strike map.svg|right|thumb|375px|[[Federal Emergency Management Agency|FEMA]]-estimated primary [[counterforce]] targets for Soviet [[ICBM]]s in 1990.  The resulting [[nuclear fallout|fall-out]] is indicated with the darkest considered as lethal to lesser fall-out yellow zones.<ref>{{cite web|title= Continental US Fallout Pattern for Prevailing Winds (FEMA-196/September 1990) |url= http://ocw.nd.edu/physics/nuclear-warfare/notes/lecture-17 |website= [[University of Notre Dame]] |url-status= dead |archive-url= https://web.archive.org/web/20110315084044/http://ocw.nd.edu/physics/nuclear-warfare/notes/lecture-17 |archive-date= March 15, 2011}}</ref>{{failed verification|date=May 2014|reason=the map in the source is different}}]]

In the late 1970s and, particularly, during the early 1980s under U.S. President [[Ronald Reagan]], the United States renewed its commitment to a more powerful military, which required a large increase in spending on U.S. military programs. These programs, which were originally part of the defense budget of U.S. President [[Jimmy Carter]], included spending on conventional and nuclear weapons systems. Under Reagan, defensive systems like the [[Strategic Defense Initiative]] were emphasized as well.

Another major shift in nuclear doctrine was the development and the improvement of the [[submarine]]-launched, nuclear-armed, ballistic missile, or [[Submarine-launched ballistic missile|SLBM]]. It was hailed by many military theorists as a weapon that would make nuclear war less likely. SLBMs—which can move with "stealth" (greatly lessened detectability) virtually anywhere in the world—give a nation a "[[second strike]]" capability (i.e., after absorbing a "first strike"). Before the advent of the SLBM, thinkers feared that a nation might be tempted to initiate a first strike if it felt confident that such a strike would incapacitate the nuclear arsenal of its enemy, making retaliation impossible. With the advent of SLBMs, no nation could be certain that a first strike would incapacitate its enemy's entire nuclear arsenal. To the contrary, it would have to fear a near-certain retaliatory second strike from SLBMs. Thus, a first strike was a much less feasible (or desirable) option, and a deliberately initiated nuclear war was thought to be less likely to start.

However, it was soon realized that submarines could approach enemy coastlines undetected and decrease the warning time (the time between detection of the missile launch and the impact of the missile) from as much as half an hour to possibly under three minutes. This effect was especially significant to the United States, Britain and China, whose capitals of [[Washington, D.C.|Washington D.C.]], [[London]], and [[Beijing]] all lay within 100 miles (160&nbsp;km) of their coasts. [[Moscow]] was much more secure from this type of threat, due to its considerable distance from the sea. This greatly increased the credibility of a "surprise first strike" by one faction and (theoretically) made it possible to knock out or disrupt the [[chain of command]] of a target nation before any counterstrike could be ordered (known as a "[[decapitation strike]]"). It strengthened the notion that a nuclear war could possibly be "won", resulting not only in greatly increased tensions and increasing calls for [[fail-deadly]] control systems, but also in a dramatic increase in military spending. The submarines and their missile systems were very expensive, and one fully equipped nuclear-powered and nuclear-armed missile submarine could cost more than the entire [[Measures of national income and output#Gross National Product|GNP]] of a [[developing country]].<ref>{{cite news|url=http://americanhistory.si.edu/subs/history/timeline/cost/index.html|title=The Cost of Submarines|access-date=2008-07-13|work=Fast Attacks and Boomers}}</ref> It was also calculated, however, that the greatest cost came in the development of ''both'' sea- and land-based anti-submarine defenses and in improving and strengthening the "chain of command", and as a result, military spending skyrocketed.

[[South Africa]] developed a nuclear weapon capability during the 1970s and early 1980s. It was operational for a brief period before being dismantled in the early 1990s.<ref>{{cite journal |last1=Liberman |first1=Peter |title=The Rise and Fall of the South African Bomb |journal=International Security |date=2001 |volume=26 |issue=2 |pages=45–86 |doi=10.1162/016228801753191132 |jstor=3092122 |s2cid=57562545 }}</ref>

According to the 1980 [[United Nations]] report ''General and Complete Disarmament: Comprehensive Study on Nuclear Weapons: Report of the Secretary-General'', it was estimated that there were a total of about 40,000 [[Historical nuclear weapons stockpiles and nuclear tests by country|nuclear warheads in existence]] at that time, with a potential combined explosive yield of approximately 13,000 [[TNT equivalent|megatons]]. By comparison, the largest volcanic eruption in [[recorded history]] when the volcano [[Mount Tambora]] erupted in 1815—turning 1816 into the [[Year Without A Summer]] due to the levels of [[global dimming]] [[sulfate]] aerosols and ash expelled—it exploded with a force of roughly 33 billion tons of TNT or 33,000 megatons of TNT this is about 2.2 million [[Little Boy|Hiroshima Bombs]],<ref>{{Cite web|url=https://www.discovermagazine.com/the-sciences/tambora-1815-just-how-big-was-the-eruption|title = Tambora 1815: Just How Big Was the Eruption?}}</ref> and ejected {{convert|175|km3|cumi|abbr=on}} of mostly rock/[[tephra]],<ref name="Stothers1984">{{cite journal | last = Stothers | first = Richard B. | journal = [[Science (journal)|Science]] | title = The Great Tambora Eruption in 1815 and Its Aftermath | volume = 224 | issue = 4654 | year = 1984 | pages = 1191–1198 | doi = 10.1126/science.224.4654.1191 | pmid = 17819476|bibcode = 1984Sci...224.1191S | s2cid = 23649251 }}</ref> that included 120&nbsp;million [[tonne]]s of sulfur dioxide as [[Mount Tambora#Global effects|an upper estimate]].<ref name="Oppenheimer2003">{{cite journal | last = Oppenheimer | first = Clive | title = Climatic, environmental and human consequences of the largest known historic eruption: Tambora volcano (Indonesia) 1815 | journal = Progress in Physical Geography | volume = 27 | issue = 2 | year = 2003 | pages = 230–259 | doi = 10.1191/0309133303pp379ra| bibcode = 2003PrPG...27..230O | s2cid = 131663534 }}</ref> A larger eruption, approximately 74,000 years ago, in [[Mount Toba]] produced {{convert|2800|km3|abbr=on}} of tephra, forming [[lake Toba]],<ref name=USGS>{{cite web |url= http://hvo.wr.usgs.gov/volcanowatch/2005/05_04_28.html |title=Supersized eruptions are all the rage! |date=April 28, 2005 |publisher=[[USGS]]}}</ref> and produced an estimated {{convert|6000|e6t|ST}} of sulfur dioxide.<ref name=robock2009>{{cite journal| author1=Robock, A.|author2=C.M. Ammann|author3=L. Oman|author4=D. Shindell|author5=S. Levis|author6=G. Stenchikov| title=Did the Toba volcanic eruption of ~74k BP produce widespread glaciation?| journal=[[Journal of Geophysical Research]] | year=2009 | volume=114 |issue=D10 | pages= D10107| doi=10.1029/2008JD011652| bibcode=2009JGRD..11410107R| doi-access=free}}</ref><ref>{{cite journal | last1 = Huang | first1 = C.Y.| last2 = Zhao | first2 = M.X.| last3 = Wang | first3 = C.C.| last4 = Wei | first4 = G.J.| title = Cooling of the South China Sea by the Toba Eruption and correlation with other climate proxies ~71,000 years ago| journal = Geophysical Research Letters | year = 2001 | volume = 28 | issue = 20 | pages = 3915–3918| doi = 10.1029/2000GL006113 | bibcode=2001GeoRL..28.3915H| doi-access = free }}</ref> The explosive energy of the eruption may have been as high as equivalent to 20,000,000 megatons (Mt) of TNT,<ref name="ocw.nd.edu">{{cite web|url=http://ocw.nd.edu/physics/nuclear-warfare/notes/lecture-18|title=Lecture 18 — Notre Dame OpenCourseWare|access-date=September 23, 2014|url-status=dead|archive-url=https://web.archive.org/web/20141010114324/http://ocw.nd.edu/physics/nuclear-warfare/notes/lecture-18|archive-date=October 10, 2014}}</ref>{{better source needed|date=September 2014}} while the asteroid created [[Chicxulub impact]], that is connected with the extinction of the dinosaurs corresponds to at least 70,000,000&nbsp;Mt of energy, which is roughly 7000 times the maximum arsenal of the US and Soviet Union.<ref name="ocw.nd.edu"/>
[[File:Massale vredesdemonstratie in Bonn tegen de modernisering van kernwapens in West, Bestanddeelnr 253-8611.jpg|thumb|230px|Protest against the deployment of [[Pershing II]] missiles in Europe, Bonn, West Germany, 1981]]

However, comparisons with [[supervolcanos|supervolcanoes]] are more misleading than helpful due to the different [[aerosol]]s released, the likely [[air burst]] fuzing height of nuclear weapons and the globally scattered location of these potential nuclear detonations all being in contrast to the singular and subterranean nature of a [[Supervolcano|supervolcanic eruption]].<ref name="Martin-1982" /> Moreover, assuming the entire world stockpile of weapons were grouped together, it would be difficult, due to the [[nuclear fratricide]] effect, to ensure the individual weapons would go off all at once. Nonetheless, many people believe that a full-scale nuclear war would result, through the nuclear winter effect, in the [[human extinction]], though not all analysts agree on the assumptions that underpin these nuclear winter models.<ref name="bmartin.cc"/>

On 26 September 1983, a Soviet early warning station under the command of [[Stanislav Petrov]] falsely detected 5 inbound [[intercontinental ballistic missile]]s from the US. Petrov correctly assessed the situation as a false alarm, and hence did not report his finding to his superiors.  It is quite possible that his actions prevented "[[World War III]]", as the Soviet policy at that time was [[Launch on warning|immediate nuclear response]] upon discovering inbound ballistic missiles.<ref>{{cite news |first=Tony |last=Long |newspaper=[[Wired (magazine)|Wired]] |title=The Man Who Saved the World by Doing ... Nothing |url=https://www.wired.com/science/discoveries/news/2007/09/dayintech_0926 |date=26 September 2007 }}</ref>

The world came unusually close to nuclear war in November 1983 when the Soviet Union thought that the NATO military exercise [[Able Archer 83]] was a ruse or "cover-up" to begin a nuclear first strike. The Soviets responded by raising readiness and preparing their nuclear arsenal for [[High-alert nuclear weapon|immediate use]]. Soviet fears of an attack ceased once the exercise concluded without incident.

=== Post-Cold War ===
{{See also|Second Cold War}}

Although the [[dissolution of the Soviet Union]] ended the [[Cold War]] in 1991 and greatly reduced the political tensions between the [[United States]] and the [[Russia|Russian Federation]], the Soviet Union's formal successor state, both countries remained in a "nuclear stand-off" due to the continuing presence of a very large number of deliverable nuclear warheads on both sides. Additionally, the end of the Cold War led the United States to become increasingly concerned with the development of nuclear technology by other nations outside of the former Soviet Union. In 1995, a branch of the U.S. Strategic Command produced an outline of forward-thinking strategies in the document "[[Essentials of Post–Cold War Deterrence]]".

In 1995, a [[Black Brant (rocket)|Black Brant sounding rocket]] launched from the [[Andøya Space Center]] caused a high alert in [[Russia]], known as the [[Norwegian rocket incident|Norwegian Rocket Incident]]. The Russians thought it might be a nuclear missile launched from an American submarine.<ref>{{cite web |url=https://www.pbs.org/wgbh/nova/article/nuclear-false-alarms/ |title=False Alarms in the Nuclear Age |author=Forden, Geoffrey |date=November 6, 2001 |publisher=Public Broadcasting System |work=NOVA }}</ref><ref>{{cite book |author=Pry, Peter |title=War scare: Russia and America on the nuclear brink |publisher=Praeger |location=New York |year=1999 |chapter=Black Brant XII |pages=214–227 |isbn=0-275-96643-7 |chapter-url=https://books.google.com/books?id=WigJ8ZsWE1QC&pg=PA214}}</ref>

In 1996, a Russian [[Continuity of government#Soviet Union and Russia|continuity of government facility]], [[Kosvinsky Mountain]], which is believed to be a counterpart to the US [[Cheyenne Mountain Complex]], was completed.<ref name="web.archive.org">{{cite web|url=http://www.windowonheartland.net/2012/02/russias-top-secret-bases.html |title=WINDOW ON HEARTLAND Geopolitical notes on Eastern Europe, the Caucasus and Central Asia |url-status=dead |archive-url=https://web.archive.org/web/20130424050959/http://www.windowonheartland.net/2012/02/russias-top-secret-bases.html |archive-date=April 24, 2013 }}</ref> It was designed to resist US [[nuclear bunker buster|earth-penetrating nuclear warheads]],<ref name="web.archive.org"/> and is believed to host the Russian [[Strategic Rocket Forces]] alternate command post, a post for the general staff built to compensate for the vulnerability of older Soviet era command posts in the Moscow region. In spite of this, the primary command posts for the [[Strategic Rocket Forces]] remains [[Kuntsevo]] in Moscow and the secondary is the Kosvinsky Mountain in the [[Ural Mountains]].{{citation needed|date=February 2023}} The timing of the Kosvinsky facilities completion date is regarded as one explanation for U.S. interest in a new nuclear "bunker buster" Earth-penetrating warhead and the declaration of the deployment of the [[B61 nuclear bomb|B-61]] mod 11 in 1997; Kosvinsky is protected by about 1000 feet of [[granite]].{{citation needed|date=February 2023}}

[[File:Treaty on the Prohibition of Nuclear Weapons.svg|thumb|230px|UN vote on adoption of the [[Treaty on the Prohibition of Nuclear Weapons]] on 7 July 2017<br />{{legend table|#008cff|Yes|#ff0000|No|#c0c0c0|Did not vote}}]]
As a consequence of the [[September 11 attacks]], American forces immediately increased their readiness to the highest level in 28 years, closing the blast doors of the NORAD's [[Cheyenne Mountain Complex|Cheyenne Mountain Operations Center]] for the first time due to a non-exercise event. But unlike similar increases during the Cold War, Russia immediately decided to stand down a large military exercise in the Arctic region, in order to minimize the risk of incidents, rather than following suit.<ref>{{cite web|url=http://www.historycommons.org/context.jsp?item=a1115putinspeaks|title=Context of '(After 11:15 a.m.) September 11, 2001: Russian President Putin Speaks with President Bush'|access-date=April 28, 2013|archive-date=February 15, 2013|archive-url=https://web.archive.org/web/20130215191043/http://historycommons.org/context.jsp?item=a1115putinspeaks|url-status=dead}}</ref>

The former chair of the [[United Nations]] [[Nuclear disarmament|disarmament]] committee stated that there are more than 16,000 strategic and tactical nuclear weapons ready for deployment and another 14,000 in storage, with the U.S. having nearly 7,000 ready for use and 3,000 in storage, and Russia having about 8,500 ready for use and 11,000 in storage. In addition, [[China]] is thought to possess about 400 nuclear weapons, [[United Kingdom|Britain]] about 200, [[France]] about 350, [[India]] about 80–100, and [[Pakistan]] 100–110. [[North Korea]] is confirmed as having nuclear weapons, though it is not known how many, with most estimates between 1 and 10. [[Israel]] is also widely believed to [[Nuclear weapons and Israel|possess usable nuclear weapons]]. NATO has [[Nuclear sharing|stationed]] about 480 American nuclear weapons in [[Belgium]], [[Netherlands|the Netherlands]], [[Italy]], [[Germany]], and [[Turkey]], and several other nations are thought to be in pursuit of an arsenal of their own.<ref>[http://lfpress.ca/newsstand/CityandRegion/2006/02/14/1441292-sun.html London Free Press – Disarmament expert warns of nuclear threat] Non functioning link</ref>

[[Pakistan]]'s nuclear policy was significantly affected by the [[Indo-Pakistani War of 1965|1965 war with India]].<ref name="Chakma2004">{{cite book|author=Bhumitra Chakma|title=Strategic Dynamics and Nuclear Weapons Proliferation in South Asia: A Historical Analysis|url=https://books.google.com/books?id=L2qmF8E8C9EC&pg=PA133|year=2004|publisher=Peter Lang|isbn=978-3-03910-382-9|page=133}}</ref> The 1971 war and India's nuclear program played a role in Pakistan's decision to go nuclear.<ref name="Chakma2012">{{citation|first=Bhumitra|last=Chakma|title=Pakistan's Nuclear Weapons|url=https://books.google.com/books?id=XTbOO0gVgR0C|date=12 October 2012|publisher=Routledge|isbn=978-1-134-13254-6|page=156}}</ref> India and Pakistan both decided not to participate in the NPT.<ref>{{harvnb|Chakma|2012|p=16}}</ref> Pakistan's nuclear policy became fixated on India because India refused to join the [[Treaty on the Non-Proliferation of Nuclear Weapons|Non-proliferation Treaty]] and remained open to nuclear weapons.<ref name="Khan2014">{{cite book|author=Zafar Khan|title=Pakistan's Nuclear Policy: A Minimum Credible Deterrence|url=https://books.google.com/books?id=XW8KBAAAQBAJ&pg=PA35|date=17 July 2014|publisher=Routledge|isbn=978-1-317-67601-0|page=23}}</ref> Impetus by Indian actions spurred Pakistan's nuclear research.<ref name="Hymans2012">{{cite book|author=Jacques E. C. Hymans|title=Achieving Nuclear Ambitions: Scientists, Politicians, and Proliferation|url=https://books.google.com/books?id=wc-hZbyPhgsC&pg=PA244|date=16 February 2012|publisher=Cambridge University Press|isbn=978-0-521-76700-2|page=244}}</ref> After nuclear weapons construction was started by President [[Zulfikar Ali Bhutto]]'s command, the chair of [[Pakistan Atomic Energy Commission]] Usmani quit in objection.<ref>{{harvnb|Chakma|2012|p=139}}</ref> The [[Kargil War|1999 war]] between Pakistan and India occurred after both acquired nuclear weapons.<ref>{{citation|first=Dr Bhumitra|last=Chakma|title=The Politics of Nuclear Weapons in South Asia|url=https://books.google.com/books?id=W-yhAgAAQBAJ&pg=PA213|date=28 April 2013|publisher=Ashgate Publishing, Ltd.|isbn=978-1-4094-7641-2|page=213}}</ref> It is believed by some that nuclear weapons are the reason a big war has not broken out in the subcontinent.<ref>{{citation|first=Bhumitra|last=Chakma|title=South Asia's Nuclear Security|url=https://books.google.com/books?id=oW7fBQAAQBAJ&pg=PT54|date=17 December 2014|publisher=Taylor & Francis|isbn=978-1-317-58688-3}}</ref> India and Pakistan still have a risk of nuclear conflict on the issue of war over [[Kashmir]]. Nuclear capability deliverable by sea were claimed by Pakistan in 2012.<ref name="Gregory2015">{{cite book|author=Shaun Gregory|title=Democratic Transition and Security in Pakistan|url=https://books.google.com/books?id=acfMCgAAQBAJ&pg=PA250|date=23 October 2015|publisher=Routledge|isbn=978-1-317-55011-2|page=250}}</ref> The aim was to achieve a "minimum credible deterrence".<ref>{{harvnb|Chakma|2014|p=–}}</ref> Pakistan's nuclear program culminated in the tests at [[Chagai-I|Chagai]].<ref>{{harvnb|Chakma|2013|p=234}}</ref> One of the aims of Pakistan's programs is fending off potential annexation and maintaining independence.<ref>{{harvnb|Chakma|2012|p=140}}</ref>

A key development in nuclear warfare throughout the 2000s and early 2010s is the [[nuclear proliferation|proliferation]] of nuclear weapons to the [[Developing country|developing world]], with [[India]] and [[Pakistan]] both publicly testing several nuclear devices, and [[North Korea]] conducting an underground nuclear test on October 9, 2006. The [[United States Geological Survey|U.S. Geological Survey]] measured a 4.2 magnitude earthquake in the area where the North Korean test is said to have occurred. A further test was announced by the North Korean government on May 25, 2009.<ref>{{cite news|url=http://news.bbc.co.uk/1/hi/world/asia-pacific/8067438.stm|title=BBC NEWS – Asia-Pacific – N Korea faces new UN resolution|date=26 May 2009}}</ref> [[Iran]], meanwhile, has embarked on a nuclear program which, while officially for civilian purposes, has come under close scrutiny by the United Nations and many individual states.

Recent studies undertaken by the [[Central Intelligence Agency|CIA]] cite the enduring [[Indo-Pakistani wars and conflicts|India-Pakistan conflict]] as the one "flash point" most likely to escalate into a nuclear war. During the [[Kargil War]] in 1999, Pakistan came close to using its nuclear weapons in case the conventional military situation underwent further deterioration.<ref>{{cite news|url=http://news.bbc.co.uk/1/hi/world/south_asia/1989886.stm|title=Pakistan 'prepared nuclear strike'|work=BBC News|date = 16 May 2002}}</ref> Pakistan's foreign minister had even warned that it would "use any weapon in our arsenal", hinting at a nuclear strike against India.<ref>"Pakistan May Use Any Weapon," The News, Islamabad, May 31, 1999</ref> The statement was condemned by the international community, with Pakistan denying it later on. This conflict remains the only war (of any sort) between two declared nuclear powers. The [[2001-2002 India-Pakistan standoff]] again stoked fears of nuclear war between the two countries. Despite these very serious and relatively recent threats, relations between India and Pakistan have been improving somewhat over the last few years. However, with the [[2008 Mumbai attacks|November 26, 2008 Mumbai terror attacks]], tensions again worsened.
{{External media |float=right | image1 = [https://www.facebook.com/photo.php?fbid=10215450632937597&set=p.10215450632937597&type=3 A geopolitical example of nuclear strike plan of ROC Army in Kinmen history. Effective Radius: 10 km; Pop.: 1.06 million]}}
[[File:World nuclear weapons.png|thumb|right|330px|Large stockpile with global range (dark blue), smaller stockpile with global range (medium blue), small stockpile with regional range (light blue).]]
Another potential geopolitical issue that is considered particularly worrisome by military analysts is a possible conflict between the [[United States]] and the [[People's Republic of China]] over [[Taiwan]]. Although economic forces are thought to have reduced the possibility of a military conflict, there remains concern about the increasing military buildup of [[China]] (China is rapidly increasing its naval capacity), and that any move toward [[Taiwan independence]] could potentially spin out of control.

[[Israel]] is thought to possess somewhere between one hundred and four hundred nuclear warheads. It has been asserted that the [[Dolphin-class submarine]]s which Israel received from Germany have been adapted to carry nuclear-armed [[Popeye (missile)|Popeye cruise missiles]], so as to give Israel a [[second strike]] capability.<ref>{{cite news|work = The Boston Globe|url= https://www.boston.com/news/world/middleeast/articles/2006/08/25/israel_buys_2_nuclear_capable_submarines_from_germany/|first = Ramit |date = 25 August 2006|last = Plushnick-Masti |title= Israel buys 2 nuclear-capable submarines from Germany|agency=Associated Press}}</ref> Israel has been involved in wars with its neighbors in the [[Middle East]] (and with other "[[non-state actor]]s" in [[Lebanon]] and [[Palestine (region)|Palestine]]) on numerous prior occasions, and its small geographic size and population could mean that, in the event of future wars, the [[Israel Defense Forces]] might have very little time to react to an invasion or other major threat. Such a situation could escalate to nuclear warfare very quickly in some scenarios.

On March 7, 2013, North Korea threatened the United States with a [[pre-emptive nuclear strike]].<ref>{{cite news|url=https://www.reuters.com/article/us-korea-north-attack-idUSBRE9260BR20130307|title=North Korea threatens nuclear strike, U.N. expands sanctions|work=Reuters|date=2013-03-07|access-date=2013-05-07}}</ref> On April 9, North Korea urged foreigners to leave [[South Korea]], stating that both countries were on the verge of nuclear war.<ref>{{Cite web|url=https://www.cbc.ca/news/world/north-korea-urges-foreigners-to-leave-south-korea-1.1314913|title=North Korea urges foreigners to leave South Korea|publisher=CBC|date=2013-04-09|access-date=2013-05-07}}</ref> On April 12, North Korea stated that a nuclear war was unavoidable. The country declared Japan as its first target.<ref>{{Cite web|url=http://www.express.co.uk/news/world/391376/North-Korea-states-nuclear-war-is-unavoidable-as-it-declares-first-target-will-be-Japan|title=North Korea states 'nuclear war is unavoidable' as it declares first target will be Japan|publisher=Express|author=Meredith, Charlotte|date=2013-04-12|access-date=2013-05-07}}</ref>

In 2014, when [[Russia–United States relations|Russia-United States]] and [[Russia–NATO relations|Russia-NATO relations]] worsened over the [[Russo-Ukrainian War]], the Russian state-owned television channel [[Russia 1]] stated that "Russia is the only country in the world that is really capable of turning the USA into radioactive ash."<ref>{{cite news| url = https://www.reuters.com/article/ukraine-crisis-russia-kiselyov/russia-can-turn-us-to-radioactive-ash-kremlin-backed-journalist-idUSL6N0MD0P920140316| work= Reuters| date = 16 March 2014|title = Russia can turn US to radioactive ash - Kremlin-backed journalist|first =Lidia |last =Kelly}}</ref> U.S. Secretary of Defense [[Ash Carter]] considered proposing deployment of [[ground-launched cruise missile]]s in Europe that could pre-emptively destroy Russian weapons.<ref>"[http://www.dw.de/us-could-potential-deploy-missiles-in-europe-to-deter-russia/a-18497133 US could potential deploy missiles in Europe to deter Russia]". [[Deutsche Welle]]. June 5, 2015.</ref>

In August 2017, [[North Korea]] warned that it might launch mid-range ballistic missiles into waters within {{convert|18|to|24|mi|km}} of [[Guam]], following an [[North Korea–United States relations#Trump administration (2017–2021)|exchange of threats]] between the governments of North Korea and the United States.<ref>{{cite news |last=Horton |first=Alex |url=https://www.washingtonpost.com/news/worldviews/wp/2017/08/09/why-north-korea-threatened-guam-the-tiny-u-s-territory-with-big-military-power/ |title=Why North Korea threatened Guam, the tiny U.S. territory with big military power |newspaper=The Washington Post |date=August 9, 2017  }}</ref><ref name=cnbc-20170810>{{cite news |url=https://www.cnbc.com/2017/08/10/north-koreas-missile-threat-to-guam-crafted-for-maximum-drama.html |title=North Korea's missile threat to Guam crafted for 'maximum drama,' says former CIA analyst |last=Daniels |first=Jeff |publisher=CNBC News |date=August 10, 2017 |access-date=August 11, 2017}}</ref> [[2017–18 North Korea crisis|Escalating tensions]] between North Korea and the United States, including threats by both countries that they could use nuclear weapons against one another, prompted a heightened state of readiness in [[Hawaii]]. The perceived ballistic missile threat broadcast all over Hawaii on 13 January 2018 was a [[2018 Hawaii false missile alert|false missile alarm]].<ref>{{cite news|url=https://www.nytimes.com/2018/01/14/world/asia/hawaii-false-alarm-north-korea-nuclear.html|work=The New York Times|title=Hawaii False Alarm Hints at Thin Line Between Mishap and Nuclear War|first=Max|last=Fisher|date=January 14, 2018}}</ref><ref>{{cite news|url=https://www.latimes.com/nation/la-na-hawaii-missile-alert-20180113-story.html|work=Los Angeles Times|title=False alert of missile attack sparks panic in Hawaii|date=January 13, 2018}}</ref>

In October 2018, the former Soviet leader [[Mikhail Gorbachev]] commented that U.S. withdrawal from the [[Intermediate-Range Nuclear Forces Treaty]] is "not the work of a great mind" and that "a new arms race has been announced".<ref>{{cite news |title=Gorbachev says Trump's nuclear treaty withdrawal 'not the work of a great mind' |url=https://www.cnbc.com/2018/10/22/gorbachev-says-trumps-nuclear-treaty-withdrawal-not-the-work-of-a-great-mind.html |last=Ellyatt |first=Holly |agency=CNBC |date=22 October 2018}}</ref><ref>{{cite web|url=https://thehill.com/policy/defense/413383-trump-stokes-debate-about-new-cold-war-arms-race|title=Trump stokes debate about new Cold War arms race|first=Ian|last=Swanson|date=27 October 2018|website=The Hill}}</ref>

In early 2019, more than 90% of world's 13,865 nuclear weapons were owned by Russia and the United States.<ref>{{cite news |first=Kelsey |last=Reichmann |title=Here's how many nuclear warheads exist, and which countries own them |url=https://www.defensenews.com/global/2019/06/16/heres-how-many-nuclear-warheads-exist-and-which-countries-own-them/ |work=[[Defense News]] |date=16 June 2019}}</ref><ref>{{cite news |title=Global Nuclear Arsenal Declines, But Future Cuts Uncertain Amid U.S.-Russia Tensions |url=https://www.rferl.org/a/nuclear-weapons-russia-start-inf-warheads/30003088.html |work=Radio Free Europe/Radio Liberty |date=17 June 2019}}</ref>

In 2019, [[Vladimir Putin]] warned that Russia would deploy [[Nuclear weapon|nuclear missiles]] in Europe if the United States deployed [[Intermediate-range ballistic missile|intermediate-range nuclear missiles]] there. Journalist [[Dmitry Kiselyov]] listed the targets in the United States, which includes [[The Pentagon]], [[Camp David]], [[Fort Ritchie]], [[McClellan Air Force Base]], and [[Jim Creek Naval Radio Station]]. [[Kremlin Press Secretary|Kremlin spokesperson]] [[Dmitry Peskov]] denies the existence of the target list.<ref>{{cite news| url = https://www.reuters.com/article/us-usa-nuclear-russia/after-putins-warning-russian-tv-lists-nuclear-targets-in-u-s-idUSKCN1QE1DM| work= Reuters| date = 25 February 2019|title = After Putin's warning, Russian TV lists nuclear targets in U.S.|first = Andrew|last = Osborn}}</ref><ref>{{cite web| url = http://tass.com/politics/1046259| work= TASS|title = Kremlin clarifies Putin never directly declared intention to aim missiles at US|date = 25 February 2019}}</ref>

On February 24, 2022, in a televised address preceding the start of Russia's [[2022 Russian invasion of Ukraine|full-scale invasion of Ukraine]], Russian President [[Vladimir Putin]] stated that Russia "is today one of the most powerful nuclear powers in the world... No one should have any doubts that a direct attack on our country will lead to defeat and dire consequences for any potential aggressor." Later in the same speech, Putin stated: "Now a few important, very important words for those who may be tempted to intervene in ongoing events. Whoever tries to hinder us, and even more so to create threats for our country, for our people, should know that Russia's response will be immediate and will lead you to such consequences that you have never experienced in your history."<ref>{{cite news |title=Defiant Putin goes to war in Ukraine with a warning for U.S., NATO |url=https://www.nbcnews.com/news/world/russia-ukraine-invasion-putin-war-warning-us-nato-rcna17497 |access-date=3 October 2022 |work=NBC News |date=24 February 2022 |language=en}}</ref><ref>{{cite news |title=Full text: Putin's declaration of war on Ukraine|url=https://www.spectator.co.uk/article/full-text-putin-s-declaration-of-war-on-ukraine |access-date=3 October 2022 |work=www.spectator.co.uk |date=24 February 2022}}</ref> On February 27, 2022, Putin publicly put his nuclear forces on alert, stating that NATO powers had made "aggressive statements".<ref>{{cite news |title=Putin puts nuclear deterrent forces on 'high alert' amid spiraling tensions over Ukraine |url=https://www.nbcnews.com/news/world/putin-orders-nuclear-deterrent-forces-high-alert-tensions-build-ukrain-rcna17853 |access-date=3 October 2022 |work=NBC News |date=27 February 2022 |language=en}}</ref> On April 14, ''The New York Times'' reported comments by CIA director [[William J. Burns (diplomat)|William Burns]], who said "potential desperation" could lead President Putin to order the use of [[tactical nuclear weapon]]s.<ref>{{Cite news |last1=Sanger |first1=David E. |last2=Barnes |first2=Julian E. |date=14 April 2022 |title=C.I.A. Director Airs Concern That Putin Might Turn to Nuclear Weapons |work=[[The New York Times]] |publication-place=Washington, D.C. |url=https://www.nytimes.com/2022/04/14/us/politics/putin-nuclear-weapons.html |url-status=live |url-access=limited |access-date=28 May 2022 |archive-url=https://web.archive.org/web/20220414234618/https://www.nytimes.com/2022/04/14/us/politics/putin-nuclear-weapons.html |archive-date=14 April 2022}}</ref> On September 21, 2022, days before declaring the annexation of additional parts of Ukraine, Putin claimed in a national television address that high NATO officials had made statements about the possibility of "using nuclear weapons of mass destruction against Russia", and stated "if the territorial integrity of our country is threatened, we will certainly use all the means at our disposal to protect Russia and our people... It's not a bluff." [[NBC News]] characterized Putin's statements as a "thinly veiled" threat that Putin was willing to risk nuclear conflict if necessary to win the war with Ukraine.<ref>{{cite news |title=Here's how seriously the West should take Putin's latest nuclear threats |url=https://www.nbcnews.com/news/world/nuclear-threat-putin-ukraine-war-bluffing-rcna48713 |access-date=3 October 2022 |work=NBC News |date=22 September 2022 |language=en}}</ref> [[Hans M. Kristensen]], director of the Nuclear Information Project at the [[Federation of American Scientists]], stated that "if you start detonating nuclear weapons in the [battlefield] you potentially get [[radioactive fallout]] that you can't control — it could rain over your own troops as well, so it might not be an advantage to do that in the field."<ref>{{cite news |title=Nuclear weapons expert says we should be 'extraordinarily concerned' about Putin nuking Ukraine |url=https://www.businessinsider.com/expert-extraordinarily-concerned-russia-could-use-nuclear-weapons-2022-9 |work=Business Insider |date=30 September 2022 |access-date=2 October 2022 |archive-date=2 October 2022 |archive-url=https://web.archive.org/web/20221002181053/https://www.businessinsider.com/expert-extraordinarily-concerned-russia-could-use-nuclear-weapons-2022-9 |url-status=live }}</ref>

According to a peer-reviewed study published in the journal ''[[Nature Food]]'' in August 2022,<ref>{{cite journal |title=Global food insecurity and famine from reduced crop, marine fishery and livestock production due to climate disruption from nuclear war soot injection |journal=[[Nature Food]] |date=15 August 2022 |doi=10.1038/s43016-022-00573-0 |last1=Xia |first1=Lili |last2=Robock |first2=Alan |last3=Scherrer |first3=Kim |last4=Harrison |first4=Cheryl S. |last5=Bodirsky |first5=Benjamin Leon |last6=Weindl |first6=Isabelle |last7=Jägermeyr |first7=Jonas |last8=Bardeen |first8=Charles G. |last9=Toon |first9=Owen B. |last10=Heneghan |first10=Ryan |volume=3 |issue=8 |pages=586–596 |pmid=37118594 |s2cid=251601831 |doi-access=free |bibcode=2022NatFd...3..586X |hdl=11250/3039288 |hdl-access=free }}</ref> a full-scale nuclear war between the U.S. and Russia would kill 360 million people directly, with a further 5 billion people dying from [[starvation]]. More than 2 billion people would die from a smaller-scale nuclear war between India and Pakistan.<ref>{{cite news |last1=Diaz-Maurin |first1=François |title=Nowhere to hide: How a nuclear war would kill you — and almost everyone else |url=https://thebulletin.org/2022/10/nowhere-to-hide-how-a-nuclear-war-would-kill-you-and-almost-everyone-else/ |work=[[Bulletin of the Atomic Scientists]] |date=20 October 2022}}</ref><ref>{{cite news |title=World Nuclear war between the U.S. and Russia would kill more than 5 billion people – just from starvation, study finds |url=https://www.cbsnews.com/news/nuclear-war-5-billion-people-starvation-deaths-study/ |work=CBS News |date=16 August 2022}}</ref> 

==Survival==
{{see also|Nuclear famine|Nuclear War Survival Skills|Civil defense}}
The predictions of the effects of a major [[countervalue]] nuclear exchange include millions of city dweller deaths within a short period of time. Some 1980s predictions had gone further and argued that a full-scale nuclear war could eventually bring about [[human extinction]].<ref name=Ehrlich/> Such predictions, sometimes but not always based on total war with nuclear arsenals at [[Cold War]] highs, received contemporary criticism.<ref name="bmartin.cc"/> On the other hand, some 1980s governmental predictions, such as [[FEMA]]'s [[CRP-2B]] and NATO's [[Carte Blanche (war game)|Carte Blanche]], have received criticism from groups such as the [[Federation of American Scientists]] for being overly optimistic. CRP-2B, for instance, infamously predicted that 80% of Americans would survive a nuclear exchange with the Soviet Union, a figure that neglected nuclear war's impacts on healthcare infrastructure, the food supply, and the ecosystem and assumed that all major cities could be successfully evacuated within 3–5 days.<ref>{{cite conference |url=https://fas.org/sgp/othergov/doe/lanl/lib-www/la-pubs/00173165.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://fas.org/sgp/othergov/doe/lanl/lib-www/la-pubs/00173165.pdf |archive-date=2022-10-09 |url-status=live |title=NUCLEAR WINTER: THE ANTHROPOLOGY OF HUMAN SURVIVAL |last1=Bumstead |first1=Pamela |date=December 6, 1985 |publisher=American Anthropological Association |location=Washington, DC |conference=84th Annual Meeting of the American Anthropological Association
 }}</ref> A number of Cold War publications advocated preparations that could purportedly enable a large proportion of civilians to survive even a total nuclear war. Among the most famous of these is ''[[Nuclear War Survival Skills]]''.<ref name="NWSS1">{{cite book|last=Kearny|first=Cresson H|title=Nuclear War Survival Skills|year=1986|publisher=Oak Ridge National Laboratory|location=Oak Ridge, TN|isbn=0-942487-01-X|pages=6–11|url=http://www.oism.org/nwss/s73p911.htm}}</ref>

To avoid injury and death from a nuclear weapon's heat flash and blast effects, the two most far-ranging prompt [[effects of nuclear weapons]], schoolchildren were taught to [[duck and cover]] by the early Cold War [[Duck and Cover (film)|film of the same name]]. Such advice is once again being given in case of [[nuclear terrorism|nuclear terrorist attacks]].<ref>{{cite web|url=https://www.theatlantic.com/national/archive/2011/01/the-unexpected-return-of-duck-and-cover/68776/|title=The Unexpected Return of 'Duck and Cover'|author=Glenn Harlan Reynolds|work=The Atlantic|date=4 January 2011}}</ref>

[[Prussian blue]], or "Radiogardase", is stockpiled in the US, along with [[potassium iodide]] and [[DPTA]], as pharmaceuticals useful in treating internal exposure to harmful [[radioisotopes]] in fallout.<ref>{{cite web|url=http://www.remm.nlm.gov/sns.htm|title=Strategic National Stockpile (SNS)|access-date=2013-10-23|archive-date=2013-10-18|archive-url=https://web.archive.org/web/20131018122046/http://www.remm.nlm.gov/sns.htm|url-status=dead}}</ref>

Publications on adapting to a changing diet and supplying nutritional food sources following a nuclear war, with particular focus on agricultural [[radioecology]], include ''Nutrition in the postattack environment'' by the [[RAND corporation]].<ref>{{cite journal |url=https://www.rand.org/pubs/research_memoranda/RM5052.html |url-access=subscription |title=Nutrition in the postattack environment |website=The RAND Corporation |date=January 1966 |last=Pogrund |first=Robert Seymour}}</ref>

The British government developed a public alert system for use during a nuclear attack with the expectation of a [[four-minute warning]] before detonation. The United States expected a warning time of anywhere from half an hour (for land-based missiles) to less than three minutes (for submarine-based weapons). Many countries maintain plans for [[continuity of government]] following a nuclear attack or similar disasters. These range from a [[designated survivor]], intended to ensure the survival of some form of government leadership, to the Soviet [[Dead Hand (nuclear war)|Dead Hand]] system, which allows for retaliation even if all Soviet leadership were destroyed. Nuclear submarines are given [[letters of last resort]]: orders on what action to take in the event that an enemy nuclear strike has destroyed the government.

A number of other countries around the world have taken significant efforts to maximize their survival prospects in the event of large calamities, both natural and manmade. For example, metro stations in [[Pyongyang Metro|Pyongyang]], [[North Korea]], were constructed {{convert|110|m|ft}} below ground, and were designed to serve as nuclear shelters in the event of war, with each station entrance built with thick steel blast doors.<ref>{{cite book|last=Robinson|first=Martin|title=Korea|url=https://archive.org/details/koreakore00robi|url-access=registration|year=2007|publisher=Lonely Planet|isbn=978-1-74104-558-1|author2=Bartlett, Ray |author3=Whyte Rob |page=[https://archive.org/details/koreakore00robi/page/364 364]}}</ref><ref>{{cite book|last=Springer|first=Chris|title=Pyongyang: the hidden history of the North Korean capital|year=2003|publisher=Entente Bt|isbn=978-963-00-8104-7|page=125}}</ref> An example of privately funded [[fallout shelter]]s is the [[Ark Two Shelter]] in [[Ontario]], Canada, and [[Autonomous building|autonomous shelters]] have been constructed with an emphasis on post-war networking and reconstruction.<ref>{{cite web|url=http://tvblogs.nationalgeographic.com/2012/03/27/doomsday-preppers-its-gonna-get-worse-tonight-at-9p-etpt/|title=Doomsday Preppers: It's Gonna Get Worse Tonight at 9P et/pt|work=[[Nat Geo TV]] Blogs|access-date=2013-10-09|archive-url=https://web.archive.org/web/20131029215900/http://tvblogs.nationalgeographic.com/2012/03/27/doomsday-preppers-its-gonna-get-worse-tonight-at-9p-etpt/|archive-date=2013-10-29|url-status=dead}}</ref>
In [[Switzerland]], the majority of homes have an underground [[blast shelter|blast]] and fallout shelter. The country has an overcapacity of such shelters and can accommodate slightly more than the nation's population size.<ref>{{cite news| url=https://www.wsj.com/articles/SB10001424052702304231204576405700994655570?mod=WSJEUROPE_hpp_sections_world | work=The Wall Street Journal | first=Deborah | last=Ball | title=Swiss Renew Push for Bomb Shelters | date=2011-06-25}}</ref><ref>{{cite news| url=http://news.bbc.co.uk/2/hi/programmes/from_our_own_correspondent/6347519.stm | work=BBC News | first=Imogen | last=Foulkes | title=Swiss still braced for nuclear war | date=2007-02-10}}</ref>

While the nuclear fallout shelters described above are the ideal long-term protection methods against dangerous radiation exposure in the event of a nuclear catastrophe, it is also necessary to have [[Radiation protection#External penetrating radiation|mobile protection equipment]] for medical and security personnel to safely assist in containment, evacuation, and many other necessary public safety objectives which ensue as a result of nuclear detonation. There are many basic shielding strategies used to protect against the deposition of radioactive material from external radiation environments. Respirators that protect against internal deposition are used to prevent the inhalation and ingestion of radioactive material and dermal protective equipment which is used to protect against the deposition of material on external structures like skin, hair, and clothing. While these protection strategies do slightly reduce the exposure, they provide almost no protection from externally penetrating [[Gamma ray|gamma radiation]], which is the cause of [[acute radiation syndrome]] and can be extremely lethal in high dosages. Naturally, shielding the entire body from high-energy gamma radiation is optimal, but the required mass to provide adequate attenuation makes functional movement nearly impossible.

Recent scientific studies have shown the feasibility of partial body shielding as a viable protection strategy against externally penetrating gamma radiation. The concept is based in providing sufficient attenuation to only the most radio-sensitive organs and tissues in efforts to defer the onset of acute radiation syndrome, the most immediate threat to humans from high doses of gamma radiation. Acute radiation syndrome is a result of irreversible bone marrow damage from high-energy radiation exposure. Due to the regenerative property of [[hematopoietic stem cell]]s found in bone marrow, it is only necessary to protect enough bone marrow to repopulate the exposed areas of the body with the shielded supply. Because 50% of the body's supply of bone marrow is stored in the pelvic region which is also in close proximity to other radio-sensitive organs in the abdomen, the lower torso is a logical choice as the primary target for protection.<ref>Waterman, Gideon; Kase, Kenneth; Orion, Itzhak; Broisman, Andrey; Milstein, Oren (2017-09). "Selective Shielding of Bone Marrow". ''Health Physics''. '''113''' (3): 195–208. {{doi|10.1097/hp.0000000000000688}}. [[International Standard Serial Number|ISSN]] 0017-9078.</ref>

==In fiction==
{{main|List of nuclear holocaust fiction}}
{{see also|Nuclear_weapons_in_popular_culture#In_fiction.2C_film.2C_and_theater|label 1=Nuclear weapons in fiction, film, and theater|apocalyptic and post-apocalyptic fiction}}
Nuclear warfare and weapons are staple elements of [[speculative fiction]].

==See also==
{{Div col|colwidth=22em}}
* [[Air Force Global Strike Command]]
* [[Basic Encyclopedia]]
* [[Broken-backed war theory]]
* [[Global catastrophic risk]]
* [[International Luxembourg Forum on Preventing Nuclear Catastrophe]]
* [[List of CBRN warfare forces]]
* [[List of states with nuclear weapons]]
* [[Mount Yamantau]]
* [[Nuclear blackout]]
* [[Nuclear briefcase]]
* [[Nuclear weapons and the United States]]
* [[Nuclear weapons debate]]
* [[People's Liberation Army Rocket Force]]
* [[Prevention of nuclear catastrophe]]
* [[Transition to war]]
* [[Treaty on the Non-Proliferation of Nuclear Weapons]]
* '''''<small>{{portal-inline|Nuclear technology}}</small>'''''
{{div col end}}

==References==
{{Reflist|30em}}

== Further reading ==
* Louis Beres, ''Apocalypse: Nuclear Catastrophe in World Politics''. The risks and consequences of nuclear war and nuclear terrorism. University of Chicago Press, Chicago, 1980. {{ISBN|9780226043609}}
* [[Laura Grego]] and David Wright, "Broken Shield:  Missiles designed to destroy incoming nuclear warheads fail frequently in tests and could increase global risk of mass destruction", ''[[Scientific American]]'', vol. 320, no. no. 6 (June 2019), pp.&nbsp;62–67.  "Nuclear-armed missiles are a political problem that technology cannot solve....  Current U.S. [[missile defense]] plans are being driven largely by [[technology]], [[politics]] and [[fear]].  Missile defenses will not allow us to escape our vulnerability to [[nuclear weapon]]s.  Instead large-scale developments will create barriers to taking real steps toward [[Nuclear disarmament|reducing nuclear risk]]s—by blocking further cuts in nuclear arsenals and potentially spurring new deployments."  (p.&nbsp;67.)
* [[Jessica T. Mathews]], "The New Nuclear Threat", ''[[The New York Review of Books]]'', vol. LXVII, no. 13 (20 August 2020), pp.&nbsp;19–21. "[P]owerful reasons to doubt that there could be a limited nuclear war [include] those that emerge from any study of history, a knowledge of how humans act under pressure, or experience of government." (p.&nbsp;20.)
* National Academies of Sciences, Engineering, and Medicine. 2025. ''[[doi:10.17226/27515|Potential Environmental Effects of Nuclear War]]''. The National Academies Press.
* [https://web.archive.org/web/20160303233628/http://www.vijbooks.com/book/232/G-G-Pamidi/Possibility-of-Nuclear-War-in-Asia-An-Indian-Perspective/9789381411513.html "Possibility of Nuclear War in Asia: An Indian Perspective"], a project of [[United Service Institution]] of India, USI, Discusses the possibility of a nuclear war in [[Asia]] from the [[India]]n point of view.
* [[Thomas Powers]], "The Nuclear Worrier" (review of [[Daniel Ellsberg]], ''The Doomsday Machine:  Confessions of a [[Nuclear War]] Planner'', New York, Bloomsbury, 2017, {{ISBN|9781608196708}}, 420 pp.), ''[[The New York Review of Books]]'', vol. LXV, no. 1 (18 January 2018), pp.&nbsp;13–15.
* [http://www.jfklibrary.org/Events-and-Awards/Forums.aspx?f=2009 "Presidency in the Nuclear Age"], conference and forum at the [[John F. Kennedy Presidential Library and Museum|JFK Library]], Boston, October 12, 2009. Four panels: "The Race to Build the Bomb and the Decision to Use It", "Cuban Missile Crisis and the First Nuclear Test Ban Treaty", "The Cold War and the Nuclear Arms Race", and "Nuclear Weapons, Terrorism, and the Presidency".
* Tom Stevenson, "A Tiny Sun" (review of [[Fred Kaplan (journalist)|Fred Kaplan]], ''The Bomb: Presidents, Generals, and the Secret History of Nuclear War'', Simon and Schuster, 2021,  384 pp.; and Keir A. Lieber and Daryl G. Press, ''The Myth of the Nuclear Revolution: Power Politics in the Atomic Age'', Cornell, 2020, 180 pp.), ''[[London Review of Books]]'', vol. 44, no. 4 (24 February 2022), pp.&nbsp;29–32. "Nuclear strategists systematically underestimate the chances of nuclear accident... [T]here have been too many close calls for accidental use to be discounted." (p.&nbsp;32.)
* [[Annie Jacobsen|Jacobsen, Annie]] (2024). ''[[Nuclear War: A Scenario]]''. Hypothetical minute-by-minute examination of how a nuclear first strike could escalate to global thermonuclear war within 72 minutes, based on interviews with military officials and declassified documents.

==External links==
{{Commons category|Nuclear warfare}}
{{wikiquote}}
* [https://web.archive.org/web/20100527215028/http://www.life.com/image/first/in-gallery/27872/fallout-after-a-nuclear-attack Fallout: After a Nuclear Attack] – slideshow by ''[[Life magazine]]''
* ''[https://fas.org/nuke/intro/nuke/7906/ The Effects of Nuclear War] {{Webarchive|url=https://web.archive.org/web/20160828040127/http://fas.org/nuke/intro/nuke/7906/ |date=2016-08-28 }}'' (1979) — handbook produced by the United States Office of Technology Assessment (hosted by the [[Federation of American Scientists]])
* ''[https://fas.org/nuke/guide/usa/napb-90/index.html Nuclear Attack Planning Base – 1990]'' (1987) — assessment of the effects of a major Soviet attack on the United States produced by the Federal Emergency Management Agency (hosted by the [[Federation of American Scientists]])
* ''[http://www.oism.org/nwss/ Nuclear War Survival Skills]'' (1979/1987) — handbook produced by [[Oak Ridge National Laboratory]] (use menu at left to navigate)
* [https://web.archive.org/web/20130820065339/http://www.carloslabs.com/node/16 Ground Zero: A Javascript simulation of the effects of a nuclear explosion in a city]
* [http://www.nationalarchives.gov.uk/catalogue/displaycataloguedetails.asp?CATLN=6&CATID=8737061&SearchInit=4&CATREF=AIR+10%2F9375 British RAF manual on the effects of nuclear explosions dated 1955]
* [http://skeptically.org/onwars/id7.html 20 Mishaps That Might Have Started Accidental Nuclear War] by Alan F. Philips, M.D.
* [http://www.nuclearfiles.org/menu/timeline/index.htm Nuclear Files.org] {{Webarchive|url=https://web.archive.org/web/20130329133717/http://www.nuclearfiles.org/menu/timeline/index.htm |date=2013-03-29 }} Interactive Timeline of the Nuclear Age
* [https://web.archive.org/web/20160304053123/http://alsos.wlu.edu/qsearch.aspx?browse=warfare%2FNuclear%25War Annotated bibliography on nuclear warfare from the Alsos Digital Library for Nuclear Issues]
* DeVolpi, Alexander, Vladimir E. Minkov, Vadim A. Simonenko, and George S. Stanford. 2004. ''Nuclear Shadowboxing: Contemporary Threats from Cold War Weaponry'', Vols. 1 and 2. Fidlar Doubleday.
* [http://www.americancombatplanes.com/nuclear_1.html Air Weapons for the Cold War] {{Webarchive|url=https://web.archive.org/web/20130724001350/http://www.americancombatplanes.com/nuclear_1.html |date=2013-07-24 }} An in depth history of American air weapons and nuclear bombs from the reference book ''American Combat Planes of the 20th Century'' by Ray Wagner
* [http://www.ibiblio.org/rcip/nuclear.html Nuclear Emergency and Radiation Resources]
* [http://nuclearsecrecy.com/nukemap/ NUKEMAP3D] – a 3D nuclear weapons effects simulator powered by Google Maps.
* [http://sresearch.scienceontheweb.net/return.php Return of Hitler, World War III]

{{Nuclear technology}}
{{Nuclear and radiation accidents and incidents}}
{{Doomsday}}
{{Authority control}}

{{DEFAULTSORT:Nuclear Warfare}}
[[Category:Nuclear warfare| ]]
[[Category:Nuclear weapons|Warfare]]