-Ms. Anuja Shah* and Mr. Kartik Kalra**

The Russia-Ukraine war has reached its zenith following Russia’s threat of use of nuclear weapons.[1] The war has its roots in the successive geopolitical expansion of the North Atlantic Treaty Organization and the American attempt of inducting Ukraine therein, prompting Russia to invade Ukraine earlier this year.[2]

This piece addresses a specific component of the Russian threat of using nuclear weapons: its illegality owing to the environmental law underpinnings of the 1997 Advisory Opinion of the International Court of Justice (“ICJ”) in Legality of the Threat or Use of Nuclear Weapons (“Nuclear Weapons Opinion”).[3] This piece argues that the Nuclear Weapons Opinion possesses deep underpinnings of evolving principles of environmental law and its corresponding principle of proportionality, both of which are violated in the Russian case. We propose that the application of the environmental underpinnings of the judgement and its corresponding principle of proportionality yields a direct conclusion of Russian divergence therefrom. In order to make this argument, we first discern the environmental law underpinnings of the Nuclear Weapons Opinion, followed by arguing for the impossibility of their satisfaction within the jus in bello principle of proportionality from the lens of environmental law. We then establish Russian divergence from this principle. The last section concludes.

Environmental Law Underpinnings of the Advisory Opinion

In the Nuclear Weapons Opinion, the Court formulated the question as “Is the threat or use of nuclear weapons in any circumstance permitted under international law?”,[4] and answered it in the negative for the most part, holding that it “cannot conclude definitively whether the threat or use of nuclear weapons would be lawful or unlawful in an extreme circumstance of self-defense, in which the very survival of a State would be at stake”.[5] This conclusion was reached via the President’s casting vote, given seven votes on opposing sides. While Weeramantry and Koroma JJ. rejected this conclusion on the impossibility of a nuclear weapon ever satisfying the principles of distinction, necessity and proportionality along with the irrevocable damage they may cause to all of humanity,[6] Oda J. rejected it on the basis that the question is not one to be answered by the Court in the first place.[7] In both the majority and the dissenting opinions, however, there is a consistent invocation of principles of environmental law to establish the general incompatibility of the threat or use of nuclear weapons with principles of jus in bello. This section culls the three environmental law underpinnings of the Advisory Opinion: transboundary harm, intergenerational equity and the precautionary principle.

Principle Against Transboundary Harm

A state’s exclusive control over its resources is a corollary of the principle of state sovereignty, meaning that each state could theoretically harm its own environment but not that of another state. The operation of this principle can be seen in early cases of international law such as the Trail Smelter Arbitration or Corfu Channel. In Trail Smelter Arbitration (US v Canada), Canada was held liable for harm caused to American crops and livestock due to the emission of sulphur dioxide from its territory that made its way to the US.[8] In holding Canada liable, the Arbitral Tribunal held that no state is entitled to use its territory in a manner that causes injury to another state.[9] In Corfu Channel, the legality of the harm caused to British warships by Albanian minefields was in question. British warships exercising their right to innocent passage were passing through an international strait, the Corfu Channel. A minefield planted by Albania exploded, killing the ship’s crew and destroying the ship. The Court, using the principle in Trail Smelter, held that no state may allow its territory to be used contrary to rights of other states.[10]

Sands proposes that the principle against transboundary harm can be considered to have acquired a customary status, given its incorporation in the Stockholm and Rio Declarations.[11] Vinuales, however, proposes that there are two distinct waves of ICJ opinion on the environment, with the first considering transboundary harm solely a product of rigid notions of state sovereignty, and the second considering the environment a universal common heritage to be protected and fostered.[12] The transition from the first wave to the second occurs, he proposes, with Barcelona Traction’s obiter on the existence of states’ erga omnes obligations.[13] In this case, Belgium petitioned the Court to demand compensation from Spain, accusing it of deliberately making a company go bankrupt whose majority shareholders were Belgian.[14] In holding that Spain did not owe an erga omnes obligation of securing the economic prosperity of the international community, it was held that Belgium has no locus to complain of the company’s treatment by Spain.[15] This pronouncement of erga omnes obligations is considered the mode to transition from the first wave to the second.

The Nuclear Weapons Opinion considers the environment a common living space belonging to everyone on the planet, including unborn generations. Vinuales proposes that this jurisprudential change in perceiving the environment not from a narrow lens of sovereignty but an expansive lens of humanity marks the inception of a second wave of doctrine altogether. The Court’s disposition towards the environment, while evolved from rudimentary notions of territoriality, hinges still on the impossibility of the operation of the principle of transboundary harm.[16] The effects of a nuclear weapon are necessary global and environment-altering, and cannot be kept within the territory of the hostile state.[17]

Principle of Intergenerational Equity

The Court remarked that the use of nuclear weapons could spell catastrophe for the environment, which wrongs not only the population that presently inhabits the planet but also future generations.[18] Weiss locates the principle of owing something to future generations as an aspect of fairness using Rawlsian methodology, where we consider ourselves to be a generation anywhere on the spectrum of time that doesn’t know in advance where.[19] Would this generation choose to be located in time after the occurrence of a nuclear Armageddon? Perhaps not. On this basis, it would be unfair for us to deprive future generations of their livelihood in pursuit our of narrow geopolitical benefits. This principle has also been incorporated in many treaties including the Paris Agreement, and can also be deemed a principle of customary international law.[20]

Principle of Precaution

The precautionary principle stands for putting in abeyance a potentially harmful act for the environment when its exact implications are scientifically indeterminable.[21] In general, it implores states to defer or abandon activities that may jeopardize the environment when the exact degree of environmental damage is beyond determination. If the state does wish to undertake the activity in question, the principle mandates the use of a lesser environmentally damaging alternative that fulfil the state’s purpose. This principle has been incorporated in the Rio Declaration,[22] and also labelled a customary principle by Sands.[23]

Weeramantry J. invokes this principle in his dissent to hold that the impossibility of its application means that the use of nuclear weapons is unlawful.[24] A “lesser environmentally damaging alternative” than a nuclear weapon that fulfils the state’s military objectives and compatible with jus in bello is always available.

Undergirding these three principles of environmental law is the principle of proportionality, which mandates that any damage to the environment be commensurate to the military advantage sought by a state.[25] A state, therefore, would be prohibited from invoking nuclear weapons in response to attacks faced by machine guns. This principle of proportionality, we propose, cannot be fulfilled via the invocation of nuclear weapons, for no military advantage is so valuable to as to destroy absolutely the environment.

Proportionality and Environmental Damage

The jus in bello principle of proportionality mandates that the military action undertaken by a state be commensurate both to the immediately foreseeable military advantage or the priorly suffered military harm.[26] This principle also applies to the environment. Thus, when a state undertakes military action or retaliates against one, it must take cognizance of the environmental damage caused by such action. In the Nuclear Weapons Opinion, the ICJ takes cognizance of a proportionality analysis that possesses environmental underpinnings:

  1. “…States must take environmental considerations into account when assessing what is necessary and proportionate in the pursuit of legitimate military objectives. Respect for the environment is one of the elements that go to assessing whether an action is in conformity with the principles of necessity and proportionality.”[27]

If minimal military advantage is accompanied by large environmental damage, or significant military advantage accompanied by extreme environmental damage, the military action of the state does not meet the standards of jus in bello and becomes unlawful. While the majority opinion only mentions the necessity of a proportionality analysis without commenting on the application of this principle to nuclear weapons, Weeramantry J.’s dissent does. He holds the following:

“[O]ne can measure only the measurable. With nuclear war, the quality of measurability ceases. Total devastation admits of no scales of measurement. We are in territory where the principle of proportionality becomes devoid of meaning.”[28]

Weeramantry J., therefore, highlights the impossibility of the coexistence of proportionality and nuclear weapons. They cannot be used to achieve a predetermined degree of military advantage or cause a predetermined degree of environmental degradation. Their use terminates the environment, and each threat of their use brings us closer to their actual deployment. The ultimate decision of the ICJ in refraining to pronounce a verdict on the use of nuclear weapons during threats to state survival can also be considered an act of proportionality, for it leaves the final balancing act between state survival and civilizational continuity to states. The principle of proportionality, therefore, must be taken into consideration in all military action, including the issuance of threats of use of nuclear weapons.

Russian Threats and Divergence from the ICJ Decision

In sum, the Nuclear Weapons Opinion demands the existence of threats to state survival for the use of nuclear weapons to be lawful, while also mandating an environment-based proportionality analysis for each military action a state undertakes. At this stage, it would be important to note that the Court held the threats of use of nuclear weapons to be illegal in every scenario of the illegality of their actual use.[29]

In the Russian case, nuclear threats have been issued by alluding to the “use [of] all the means at our disposal” when threats to Russian territorial integrity are discerned.[30] By no means, however, can the threshold of the ICJ’s pronouncement of state survival be considered so low as to permit threats whenever territorial integrity is threatened. This question must be answered in a manner distinct from that of jus ad bellum, which is the question of the justness of the Russian invasion of Ukraine. Regardless of the answer to that question, the standard to be maintained during casualties by virtue of the jus in bello principle of proportionality to the environment continues to bind Russia. Given that Russian state survival isn’t threatened by its own invasion of Ukraine and the acquisition of quantifiable military advantage by Russia via the use of nuclear weapons is unlikely, there exists no international law-based justification to the Russian threat of use of nuclear weapons.


Principles of environmental law, therefore, have been integral to the Court’s verdict on the general illegality of the threat or use of nuclear weapons. The Court took note of foundational principles of transboundary harm and intergenerational equity along with the precautionary principle in pronouncing its verdict. We submit, therefore, that the Russian threat of use of nuclear weapons is unlawful owing to the environmental law underpinnings of the Nuclear Weapons Opinion.



* Research Fellow, Centre for Environmental Law, Education, Research & Advocacy (CEERA), National Law School of India University (NLSIU), Bengaluru

** Student, National Law School of India University (NLSIU), Bengaluru.

[1] Issac Chotiner, ‘How Close is Vladimir Putin to a Nuclear War?’ New Yorker (11 October 2022 <> accessed 13 October 2022.

[2] ‘Understanding the Roots of Russia’s War in Ukraine’ Bloomberg (2 March 2022) <> accessed 17 October 2022.

[3] Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, 1.C.J. Reports 1996, 226.

[4] ibid 238.

[5] ibid 266.

[6] ibid 553.

[7] ibid 373.

[8] Trail Smelter Case (United States, Canada) 3 Reports of International Arbitral Awards 1905.

[9] ibid 1963.

[10] Corfu Channel (United Kingdom of Great Britain and Northern Ireland v. Albania) 1949.

[11] Phillipe Sands, Principles of International Environmental Law (2nd edn, Cambridge University Press 2003) 236.

[12] Jorge Vinuales, ‘The Contribution of the International Court of Justice to the Development of International Environmental Law: A Contemporary Assessment’ (2008) 32 Fordham International Law Journal 232.

[13] ibid 244.

[14] Case Concerning the Barcelona Traction, Light and Power Co. Ltd. (Belgium v. Spain) (1970).

[15] ibid [33].

[16] Nuclear Weapons Opinion (n 3) 241.

[17] Deborah L. Houchins, ‘Extending the Application of the ICJ’s July 8, 1996, Advisory Opinion to Environment-Altering Weapons in General: What Is the Role of International Environmental Law in Warfare’ (2002) 22 Journal of Land Resources and Environmental Law 463.

[18] Nuclear Weapons Opinion (n 3) 241.

[19] Edith Brown Weiss, ‘Climate Change, Intergenerational Equity, and International Law’ (2008) Vermont Journal of Environmental Law 615.

[20] Sands (n 11) 257.

[21] Sands (n 11) 268.

[22] Principle 15, Rio Declaration, 1992.

[23] Sands (n 11)

[24] Nucleae Weapons Opinion (n 3) 502.

[25] Neil AF Popovic, ‘Humanitarian Law, Protection of the Environment, and Human Rights’ (1995) 8 Georgetown International Environmental Law Review 67.

[26] ibid.

[27] Nuclear Weapons Opinion (n 3) 242.

[28] Nuclear Weapons Opinion (n 3) 515.

[29] ibid 246.

[30] C Raja Mohan, ‘Russia’s nuclear threat may force Europe to build a nuclear arsenal’ The Indian Express (New Delhi, 27 September 2022) <> accessed 17 October 2022.

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