1 ICRC, “The end of hostilities and the future tasks of the Red Cross”, Circular Letter No. 370 to the Central Committees of the Red Cross Societies, 5 September 1945; ICRC, Report of the International Committee of the Red Cross on its activities during the Second World War, ICRC, Geneva, May 1948, Vol. I, pp. 688–690.

2 See the following resolutions of the International Conference of the Red Cross and Red Crescent: Resolution 24 of the 17th International Conference of the Red Cross and Red Crescent, Stockholm, 1948; Resolution 18 of the 18th International Conference of the Red Cross and Red Crescent, Toronto, 1952; Resolution 18 of the 19th International Conference of the Red Cross and Red Crescent, New Delhi, 1957; Resolution 28 of the 20th International Conference of the Red Cross and Red Crescent, Vienna, 1965; Resolution 14 of the 21st International Conference of the Red Cross and Red Crescent, Istanbul, 1969; Resolution 14 of the 22nd International Conference of the Red Cross and Red Crescent, Tehran, 1973; Resolution 12 of the 23rd Conference, Bucharest, 1977; and Resolution 13 of the 24th International Conference of the Red Cross and Red Crescent, Manila, 1981.

3 Statement by Jakob Kellenberger, president of the ICRC, to the Geneva diplomatic corps, Geneva, 20 April 2010, available at https://www.icrc.org/en/doc/resources/documents/statement/nuclear-weapons-statement-200410.htm.

4 2010 Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons, Final Document, NPT/CONF.2010/50, Vol. I, Conclusions and recommendations for follow-on actions, section I(A)(v), p. 19.

5 Council of Delegates, Resolution 1, “Working towards the elimination of nuclear weapons”, CD/11/R1, ICRC, 2011.

6 United Nations General Assembly, Resolution 71/258, “Taking forward multilateral nuclear disarmament negotiations”, A/RES/71/258, 23 December 2016.

7 See “Elements of a treaty to prohibit nuclear weapons”, A/CONF.229/2017/WP.2, and “Comments of the International Committee of the Red Cross on key provisions of the Draft Convention on the Prohibition of Nuclear Weapons”, A/CONF.229/2017/CRP.2, submitted by the ICRC to the United Nations conference to negotiate a legally binding instrument to prohibit nuclear weapons, leading towards their total elimination, 31 March 2017 and 14 June 2017 respectively.

8 Treaty on the Prohibition of Nuclear Weapons (A/CONF.229/2017/8), adopted at the United Nations conference to negotiate a legally binding instrument to prohibit nuclear weapons, leading towards their total elimination, New York, 7 July 2017.

9 The term “nuclear weapons” is used here to designate any explosive device triggered by nuclear fission or fusion. It does not apply to weapons or ammunition that contain radioactive components but do not bring about a process of fission or fusion, such as a “dirty bomb”. (“A “dirty bomb” is a type of “radiological dispersal device” that combines a conventional explosive, such as dynamite, with radioactive material”; see US Nuclear Regulatory Commission Backgrounder on Dirty Bombs, February 2020).

10 ICRC, “The Effects of Nuclear Weapons on Human Health”, Information Note no. 1, 2013; see also ICRC, International Humanitarian Law and the Challenges of Contemporary Armed Conflicts, ICRC, 2015, 32IC/15/11, pp. 56–59, available at https://www.icrc.org/en/download/file/15061/32ic-report-on-ihl-and-challenges-of-armed-conflicts.pdf (subsequent references to this report will cite it as the IHL Challenges Report 2015); and Maresca, L. & Mitchell, E., “The human costs and legal consequences of nuclear weapons under international humanitarian law”, International Review of the Red Cross, Vol. 97, No. 899, July 2016, pp. 621–645CrossRefGoogle Scholar. Regarding new evidence about the humanitarian impacts of nuclear weapons, see ICRC-IFRC report, The humanitarian impacts and risks of the use of nuclear weapons, August 2020.

11 See International Court of Justice, “Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons”, ICJ, 8 July 1996, paragraph 35.

12 As reported in Coupland, R. and Loye, D., “Who will assist the victims of use of nuclear, radiological, biological or chemical weapons – and how?”, International Review of the Red Cross, Vol. 89, No. 866, June 2007, pp. 329–344Google Scholar, and Coupland, R. and Loye, D., “International assistance for victims of use of nuclear, radiological, biological and chemical weapons: time for a reality check?”, International Review of the Red Cross, Vol. 91, No. 874, June 2009, pp. 329–340CrossRefGoogle Scholar. The ICRC has concluded in particular that an effective means of assisting a substantial portion of survivors of a nuclear detonation, while adequately protecting those delivering assistance, is not currently available at national level and not feasible at international level. It has also concluded that it is highly unlikely that the immense investment required to develop such capacity will ever be made, and even if it were made, it would likely remain insufficient. See ICRC president Peter Maurer's 2013 statement to the Oslo Conference on the Humanitarian Impacts of Nuclear Weapons, March 2013, and the interview of 4 March 2013 with Gregor Malich, head of the ICRC's Chemical, Biological, Radiological and Nuclear Response Operational Response Project, “No way to deliver assistance in the event of a nuclear explosion”.

13 ICRC-IFRC report, The humanitarian impacts and risks of the use of nuclear weapons, ICRC/IFRC, Geneva, August 2020, paragraphs 3–8.

14 Council of Delegates of the International Red Cross and Red Crescent Movement, Resolution 1, CD/11/R1, 2011, OP3. The “existing international obligations” essentially refer to the obligation to negotiate nuclear disarmament under Article VI of the NPT and customary law.

15 Cf Borrie, J., Caughley, T. and Wan, W. (eds), Understanding Nuclear Weapon Risks, UNIDIR, 2017, p. 11Google Scholar.

16 ICRC Briefing Note for National Societies, “Reducing the Risk of Nuclear Weapon Use and Accidental Detonation”, September 2016; and ICRC-IFRC report, The humanitarian impacts and risks of the use of nuclear weapons, ICRC/IFRC, Geneva, August 2020, section III.

17 Peter Maurer, “Nuclear weapons: Averting a global catastrophe”, appeal by the president of the ICRC, Geneva, 2018.

18 See 2010 Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons, Final Document, NPT/CONF.2010/50 (Vol. I), “Conclusions and recommendations for follow-on actions”, section IA(v), p. 19; also see United Nations General Assembly, Resolution 75/63, A/RES/75/63, 7 December 2020, OP 5, 7, 9 and 10; Resolution 74/46, A/RES/74/46, 12 December 2019, OP 6, 7 and 10; and Resolution 73/60, A/RES/73/60, 5 December 2018, OP 1 and 2.

19 See 2010 Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons, Final Document, NPT/CONF.2010/50 (Vol. I), Actions 23–46. Other instruments require states to take certain nuclear non-proliferation measures, such as United Nations Security Council, Resolution 1540, S/RES/1540, 2004, and export control agreements.

20 ICRC Briefing Note, “Safeguards and the Treaty on the Prohibition of Nuclear Weapons”, October 2018.

21 See Council of Delegates, Resolution 4, “Working towards the elimination of nuclear weapons: 2018–2021 action plan”, CD/17/R4, 2017, paras. 2 and 4.

22 See Council of Delegates progress report, “Working towards the elimination of nuclear weapons: 2018–2021 action plan (Resolution 4 of the 2017 Council of Delegates)”, CD/19/19, pp. 5–6.

23 Resolution 4 of the Council of Delegates, “Working towards the elimination of nuclear weapons: 2018–2021 action plan”, 2017, CD/17/R4, OP4.

24 Ibid.

25 Treaty on the Prohibition of Nuclear Weapons, PP18.

26 ICRC president's speech at the 2018 signing ceremony of the TPNW.

27 PP19 of the TPNW reads “Recognizing the vital importance of the Comprehensive Nuclear Test-Ban Treaty and its verification regime as a core element of the nuclear disarmament and non-proliferation regime”.

28 United Nations General Assembly Resolution, “Establishment of a Commission to Deal with the Problems Raised by the Discovery of Atomic Energy”, A/RES/1(1), OP 5(b).

29 See, e.g. United Nations General Assembly, Resolution 808 A (IX), A/RES/808(IX), 4 November 1954, Resolution 35/152, A/RES/35/152, D, 12 December 1980, Resolution 51/450, A/RES/51/450, 10 December 1996, Resolution 59/77, A/RES/59/77, 3 December 2004 and Resolution 70/57, A/RES/70/57, 7 December 2015; United Nations Security Council, Resolution 984, S/RES/984, 11 April 1995 and Resolution 2310, S/RES/2310, 23 September 2016; European Parliament Resolution 2016/2936(RSP), 27 October 2016; Association of Southeast Asian Nations, Plan of Action to Strengthen the Implementation of the Treaty on the South-East Asia Nuclear Weapon-Free Zone (2018–2022), 4 August 2017; Community of Latin American and Caribbean States, Special Declaration of the Community of Latin American and Caribbean States on the Urgent Need for a Nuclear Weapon Free World, 29 January 2015.

30 Treaty on the Prohibition of Nuclear Weapons, Articles 4(2) and 8(1)(b).

31 International Court of Justice, “Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons”, ICJ, 8 July 1996, para. 105(2)(F).

32 Ibid., para. 99.

33 Ibid., para. 103.

34 See Council of Delegates, Resolution 1, “Working towards the elimination of nuclear weapons”, CD/11/R1, 2011, para. 2.

35 In December 2014, at the last of the three “humanitarian impacts” conferences held in Vienna, the director of International Law and Policy at the ICRC stated that “the new evidence that has emerged in the last two years about the humanitarian impact of nuclear weapons casts further doubt on whether these weapons could ever be used in accordance with the rules of customary IHL”, a position reaffirmed in the IHL Challenges Report 2015. Likewise, in February 2015, the ICRC president stated that new evidence only strengthened existing doubts about the lawfulness of using nuclear weapons. He added: “With every new piece of information, we move further away from any hypothetical scenario where the humanitarian consequences of the use of nuclear weapons could be compatible with international humanitarian law”; see “Nuclear weapons: Ending a threat to humanity”, a speech given by Mr Peter Maurer, president of the International Committee of the Red Cross, to the diplomatic community in Geneva (18 February 2015). In his opening statement to the March 2017 session of the United Nations conference negotiating the TPNW, the ICRC president said that “[e]vidence of the indiscriminate effects and unspeakable suffering caused by nuclear weapons raise significant doubts about their compatibility with IHL”. Subsequently, at the ceremony for the entry into force of the TPNW on 22 January 2021, he stated that it is “extremely doubtful” that nuclear weapons could ever be used in accordance with IHL.

36 PP10 of the TPNW considers that “any use of nuclear weapons” would be contrary to IHL. In its explanation of its vote to adopt the Treaty on 7 July 2017, Sweden stated it did “not subscribe to the language” of this preambular paragraph, and maintained that, in its view, the “generally contrary” language of the 1996 advisory opinion of the International Court of Justice on nuclear weapons was the correct statement of the law.

37 International Court of Justice, “Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons”, ICJ, 8 July 1996, paras. 79 and 85–86.

38 2010 Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons, Final Document, NPT/CONF.2010/50, Vol. I, Conclusions and recommendations for follow-on actions, section I(A)(v), p. 19.

39 See PP8 and PP9 of the TPNW.

40 International Court of Justice, “Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons”, ICJ, 8 July 1996, para. 105 2(E).

41 ICRC, IHL Challenges Report 2015, p. 59.

42 L. Doswald-Beck, “International humanitarian law and the Advisory Opinion of the International Court of Justice on the legality of the threat or use of nuclear weapons”, International Review of the Red Cross, No. 316, 1997, p. 54. Also see Military Tribunal at Nuremberg, Trial of Erhard Milch, 20 December 1946–17 April 1947, summarized in Law Reports of Trials of War Criminals, Vol. VII, The United Nations War Crimes Commission, 1948, pp. 27–: (in response to the argument of the defence that the law of war is suspended in a situation of total warfare, the judges stated “[w]ith all its horror modern war still ‘is not a condition of anarchy and lawlessness between the belligerents, but a contention in many respects regulated, restricted, and modified by law.’”); also see Military Tribunal at Nuremberg, Trial of Krupp, 1948, summarized in Law Reports of Trials of War Criminals, Vol. X, The United Nations War Crimes Commission, 1949, pp. 138–139 (“the contention that the rules and customs of warfare can be violated if either party is hard pressed in any way must be rejected. […] [T]hese rules and customs of warfare are designed specifically for all phases of war. They comprise the law for such emergency.”).

43 Article 51(4)(a) of Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of International Armed Conflicts, 8 June 1977, and customary IHL (cf ICRC Customary International Humanitarian Law Study, p. 43).

44 Report on Nuclear Employment Strategy of the United States, Specified in Section 491 of 10 U.S.C., 12 June 2013, pp. 4–5; Office of the Secretary of Defense, Nuclear Posture Review, February 2018 (2018 US Nuclear Posture Review), p. 23; and Joint Chiefs of Staff, Nuclear Operations, 11 June 2019, pp. 111–114.

45 W. Burr (ed.), U.S. Cold War Nuclear Target Lists Declassified for First Time, The Nuclear Vault, National Security Archive, George Washington University, 22 December 2015; Mount, A. and Vaddi, P., Better Informing a President's Decision on Nuclear Use, Lawfare, 9 November 2020Google Scholar.

46 For example, United Kingdom doctrine states that the legality of the use of nuclear weapons “depends upon the application of the general rules of international law including those regulating the use of force and the conduct of hostilities” and “[w]hether the use, or threatened use, of nuclear weapons in a particular case is lawful depends on all the circumstances.” The United Kingdom “would only consider using nuclear weapons in self-defence, including the defence of its NATO allies, and even then only in extreme circumstances”; see Joint Service Manual of the Law of Armed Conflict (JSP 383), 2004 edition, p. 117.

47 ICRC Customary International Humanitarian Law Study, Rule 145: https://ihl-databases.icrc.org/customary-ihl/eng/docs/v1_rul_rule145.

48 See for example United Nations General Assembly Resolution 2675 (XXV), which affirmed the principle that “civilian populations, or individual members thereof, should not be the object of reprisals” as a basic principle for the protection of civilian populations in armed conflict (GA/RES/2675 (XXV), OP 7).

49 See ICRC Customary International Humanitarian Law Study, Rule 145, pp. 513, 520–523.

50 For example, the condition of use as a last resort, i.e. use only after all other means (political, diplomatic, economic, etc.) have been exhausted, seems unrealistic since nuclear doctrines call for immediate retaliation to a nuclear attack, this being a key element of the nuclear deterrence theory applied by all nuclear-armed states.

51 For further discussion of the use of nuclear weapons as a belligerent reprisal tool, see L. Maresca & E. Mitchell, at pp. 642–643.

52 In its 1996 advisory opinion, the International Court of Justice found that radiation was “peculiar to nuclear weapons”, accounting in part for their “unique characteristics”, and that such radiation “would affect health, agriculture, natural resources and demography over a very wide area” (para. 35).

53 See e.g. Matthew McKinzie et al., “Calculating the Effects of a Nuclear Explosion at a European Military Base”, presentation to the Vienna Conference on the Humanitarian Impact of Nuclear Weapons, December 2014. Modern environmental modelling techniques have demonstrated that even a “small-scale” use of some 100 nuclear weapons against urban targets would, in addition to spreading radiation around the world, lead to a cooling of the atmosphere, shorter growing seasons, food shortages and a global famine in which it is estimated over a billion people would perish; see Alan Robock et al., “Global Famine after a Regional Nuclear War: Overview of Recent Research”, presentation to the Vienna Conference on the Humanitarian Impact of Nuclear Weapons, December 2014.

54 The heat generated by the explosion can be expected to cause severe burns to exposed skin up to 3 km from the epicentre, and massive destruction of buildings and infrastructure within several kilometres; see the IHL Challenges Report 2015, p. 57.

55 International Court of Justice, “Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons”, ICJ, 8 July 1996, paras 35 and 95 respectively.

56 The ICRC already drew a similar conclusion in 1950: “Atomic weapons and non-directed missiles: ICRC statement, 5 April 1950”, International Review of the Red Cross, Supplement, Vol. 3, No. 4, 1950. See also Maresca, L. and Mitchell, E., “The human costs and legal consequences of nuclear weapons under international humanitarian law”, International Review of the Red Cross, Vol. 97, No. 899, 2015, p. 632CrossRefGoogle Scholar.

57 L. Maresca and E. Mitchell, p. 635.

58 ICRC, International humanitarian law and the challenges of contemporary armed conflicts: Recommitting to protection in armed conflict on the 70th anniversary of the Geneva Conventions, ICRC, Geneva, 2019 (IHL Challenges Report 2019), pp. 8–9.

59 ICRC-IFRC report, The humanitarian impacts and risks of the use of nuclear weapons, ICRC/IFRC, Geneva, August 2020.

60 Some have interpreted the conclusion put forward by the International Court of Justice as meaning that IHL might not apply in certain extreme cases of self-defence under the jus ad bellum. The ICRC has firmly rejected this, and such an interpretation has been decried by some authors as an application of the discredited doctrine of Kriegsraison, as mentioned above (see fn 34).

61 In its 1996 advisory opinion, the International Court of Justice pointed out the weakness of such arguments in the following terms (para. 94): “The Court would observe that none of the States advocating the legality of the use of nuclear weapons under certain circumstances, including the ‘clean’ use of smaller, low-yield, tactical nuclear weapons, has indicated what, supposing such limited use were feasible, would be the precise circumstances justifying such use; nor whether such limited use would not tend to escalate into the all-out use of high yield nuclear weapons.”

62 International Court of Justice, “Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons”, ICJ, 8 July 1996, para. 95.

63 Ibid., para. 78.

64 ICRC-IFRC, The humanitarian impacts and risks of the use of nuclear weapons, ICRC/IFRC, Geneva, August 2020, para. 5–8; ICRC, IHL Challenges Report 2015, p. 58; ICRC, “Long-term Health Consequences of Nuclear Weapons: 70 years on Red Cross Hospitals still treat Thousands of Atomic Bomb Survivors”, Information Note No. 5, July 2015; ICRC, “The Effects of Nuclear Weapons on Human Health”, Information Note No. 1, 2013.

65 Article 35(3) of Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of International Armed Conflicts, prohibits the use of methods and means of warfare which are intended, or may be expected, to cause widespread, long-term, and severe damage to the natural environment. This rule, however, has not become part of customary law with regard to nuclear weapons as certain states, notably France, the United Kingdom and the United States, have consistently objected to its application to nuclear weapons; see ICRC, Guidelines on the Protection of the Environment in Armed Conflict, Geneva, 2020, at para. 48.

66 ICRC-IFRC, The humanitarian impacts and risks of the use of nuclear weapons, ICRC/IFRC, Geneva, August 2020, para. 5 and 6; ICRC, IHL Challenges Report 2015, p. 58; ICRC, “Climate Effects of Nuclear War and Implications for Global Food Production”, Information Note No. 2, 2013. Already in 1996, the International Court of Justice had noted that the ionizing radiation released by a nuclear explosion could “damage the future environment, food and marine ecosystem, and cause genetic defects and illness to future generations” and that nuclear weapons could potentially destroy “the entire ecosystem of the planet”; see International Court of Justice, “Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons”, ICJ, 8 July 1996, para. 35.

67 See the commentary on Article 36 of the Protocol Additional to the Geneva Conventions of 12 August 1949 and relating to the Protection of Victims of International Armed Conflicts in ICRC, Commentary on the Additional Protocols of 8 June 1977 to the Geneva Conventions of 12 August 1949, ICRC, Geneva, Martinus Nijhoff Publishers, 1987, para. 1469.

68 See Treaty on the Prohibition of Nuclear Weapons, PP11.

69 See also Article 63(3) of Convention (I) for the Amelioration of the Condition of the Wounded and Sick in Armed Forces in the Field, stipulating that “The denunciation… shall in no way impair the obligations which the Parties to the conflict shall remain bound to fulfil by virtue of the principles of the law of nations, as they result from the usages established among civilized peoples, from the laws of humanity and the dictates of the public conscience.” (replicated in Article 62 of the Convention (II) for the Amelioration of the Condition of Wounded, Sick and Shipwrecked Members of Armed Forces at Sea, Article 142 of the Convention (III) relative to the Treatment of Prisoners of War, and Article 158 of the Convention (IV) relative to the Protection of Civilian Persons in Time of War).

70 It has been debated whether the “principles of humanity” and the “dictates of public conscience” are separate, legally binding yardsticks against which a weapon can be measured in law, or whether they are merely moral guidelines. The view of the ICRC is that since “they reflect public conscience; the principles of humanity actually constitute a universal reference point and apply independently of the Protocol.” See ICRC, Commentary on the Additional Protocols of 8 June 1977 to the Geneva Conventions of 12 August 1949, 1987, Geneva, Martinus Nijhoff Publishers, para. 4434.

71 See Treaty on the Prohibition of Nuclear Weapons, PP24.

72 ICRC, Millennials on War, ICRC, January 2020.

73 International Court of Justice, “Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons”, ICJ, 8 July 1996, para. 78.

74 One state argued in front of the International Court of Justice that threatening to use nuclear weapons would be incompatible with the obligation to comply with and ensure respect for IHL. Nystuen, G., “Threats of use of nuclear weapons and international humanitarian law”, in Nystuen, G., Casey-Maslen, S., Bersagel, A. Golden, Nuclear Weapons Under International Law, Cambridge University Press, 2014, pp. 161–162CrossRefGoogle Scholar. See also International Court of Justice, “Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons”, ICJ, 8 July 1996, para. 105: “the threat or use of nuclear weapons would generally be contrary to the rules of international law applicable in armed conflict, and in particular the principles and rules of humanitarian law”.

75 See Article 1(1)(d) of the TPNW.

76 United States, DoD Dictionary of Military and Associated Terms, December 2020, p. 63.

77 See, for example, Patricia Lewis et al., Too Close for Comfort: Cases of Near Nuclear Use and Options for Policy, Chatham House, 2014; and J. Borrie et al., Understanding Nuclear Weapon Risks, UNIDIR, 30 March 2017.

78 ICRC-IFRC report, The humanitarian impacts and risks of the use of nuclear weapons, ICRC/IFRC, Geneva, August 2020, para. 14, available at https://www.icrc.org/en/document/humanitarian-impacts-and-risks-use-nuclear-weapons.

79 Speech by ICRC president Peter Maurer at the TPNW signing and ratification ceremony, 26 September 2019.

80 Speech by ICRC president Peter Maurer at the TPNW signing ceremony, 26 September 2018.