War kills. It Also Warms: Holding States Responsible for the Damages to Climate in Armed Conflicts

[Davit Khachatryan is a lecturer at American University of Armenia and Russian-Armenian University specializing in public international law, alternative dispute resolution, investment law, international humanitarian law, and security.

Gor Samvel is an MSCA post-doctoral researcher at the UiT- the Arctic University of Norway, Faculty of Law and the Norwegian Centre for the Law of the Sea, specializing in international environmental law.]

Introduction

While the immediate human toll of armed conflict commands the center of moral and legal attention, the climate consequences of modern warfare have begun to demand their own reckoning. Within fourteen days of the US-Israel-Iran exchanges, estimated greenhouse gas emissions reached five million tonnes of carbon dioxide equivalent. The war in Gaza generated an estimated 32 million tonnes over two years. Russia’s war in Ukraine, between 2022 and 2024, is estimated to have produced approximately 230 million tonnes. Against these figures, the daily military carbon footprint of approximately 5.5% of global emissions acquires a different gravity. Where the underlying conflict generates emissions as a consequence of internationally wrongful acts, those emissions are part of the harm for which reparation might be owed. The US-Israel-Iran conflict, the war in Gaza, and Russia’s aggression against Ukraine together illustrate a pattern that international law has been slow to name directly: states responsible for illegal use of force  bear   legal responsibility for the damage they cause to Earth’s climate system specifically. Against this background, the time has come to map the paths to accountability. This piece contends that states responsible for wars of aggression are legally accountable under existing international law for the climate damage those wars cause, and that the architecture for making that argument before international tribunals, while underused, is already in place. It does so by outlining the international legal framework protecting the climate system during armed conflict and examining certain aspects of operationalizing that framework. 

International Law Protecting the Climate System in Times of War

The acknowledgment of the  climate impacts of armed conflicts is a relatively recent development (here, here, and here). Nevertheless, international humanitarian law’s (IHL) layered system of protection for the natural environment affords protection also to the climate system. The climate system falls within the IHL framework on the protection of the natural environment. The latter, understood as “everything that exists or occurs naturally… including elements that are or may be the product of human intervention” (IHL Guidance), encompasses the former that is composed of such various components as atmosphere, ocean, ice and snow cover, the many mutual interactions between them, and large variety of physical, chemical and biological processes (IPCC, Climate System, Overview, ICJ Advisory Opinion on Climate, PP 274-279).

The first layer of protection for the climate system derives from customary rules, as outlined in Rules 43, 44, and 45 of the ICRC’s Customary IHL Study (here). As a civilian object, the climate system is to be treated within the confines of the general principles of distinction, proportionality, precaution (Rule 43), and prohibition of indiscriminate attacks (here and here). It is further subject to specific obligations concerning the preservation and protection from unlawful choice of methods and means of warfare (Rule 44), implying the duty to take all feasible precautions to avoid or minimize collateral environmental damage during an attack (ICRC 2020 Guidelines, Rule 8).

The absolute protection, albeit with a high threshold, provided to the climate system that goes beyond necessity or proportionality (here) is the prohibition of the use of methods or means of warfare that are intended or may be expected to cause widespread, long-term, and severe damage to the climate system, and the use of the destruction of the natural environment as a weapon (Rule 45). While the customary status of the general principles, and the specific obligations to preserve and to protect, is not seriously contested by any of the belligerents (e.g., PERAC Principles 13(1), 14); ICRC 2020 Guidelines, Rule 1), the same claim cannot be made in relation to absolute prohibition. Principle 13(2) of the ILC’s 2022 Draft principles on protection of the environment in relation to armed conflicts (PERAC), which reproduces the substance of that prohibition, was qualified with the chapeau “[s]ubject to applicable international law,” signaling that the customary status of the cumulative threshold remains contested (here). State practice, specifically that of France, the United Kingdom, and the United States, indicates limits in acceptance of the prohibition in relation to nuclear weapons (here).  

The treaty layer of protection largely consolidates the customary rules. Articles 35(3) and 55(1) of Additional Protocol I (AP I) to the Geneva Conventions enshrine, in treaty form, the same prohibition of widespread, long-term, and severe damage to the climate system. In parallel, under the Convention on the Prohibition of Military or Any Other Hostile Use of Environmental Modification Techniques (ENMOD), the climate system as a whole, and its components, dynamics, and structure cannot be modified (changed) through deliberate manipulation by environmental modification techniques (Articles I, II). Not least, the intentional launching of an attack in the knowledge that it will cause the same cumulative effects of widespread, long-term, and severe damage to the climate system or any of its components in excess of the concrete and direct overall military advantage, may entail individual criminal responsibility under Article 8.2,b (iv)) of the Rome Statute of the International Criminal Court (here).

As for the continued applicability of international environmental law (IEL) during an armed conflict, absent explicit treaty provision on such applicability, it remains contested (here and here). Nonetheless, according to some of the authoritative interpretations, both customary and treaty-based IEL rules concerning the climate system should continue to apply (here and here), or at a minimum, they must be duly taken into account in the application of IHL (here), unless displaced under the lex specialis principle (here). At the level of customary principles, such conflict is unlikely, given the compatibility of core principles across both regimes, including the principles of precaution, distinction, and due diligence. (Trail Smelter Arbitration; Stockholm Principle 21;  Rio Principle 2; Climate Advisory Opinion). The observed convergence goes beyond customary law, one example being a situation where compliance with IHL conduct-of-hostilities obligations might be factored into a judgment on a belligerent State’s compliance with the due diligence obligations under the Paris Agreement when the ratio of war-generated GHG emissions in the pledged nationally determined contributions is concerned.

Invoking the Responsibility of States for Breach

The first condition for establishing international responsibility of a state for conduct posing harm to the climate system is that such conduct constitutes a breach of IHL obligations. In light of the foregoing, identification of relevant obligations should not present significant difficulty under customary international law for most States. This does not hold for the treaties for obvious reasons, including non-ratification. For instance, among states involved in the conflicts in question, only Ukraine, the State of Palestine, and Russia are parties to the AP I (here).

A wartime conduct that might potentially be characterized as a breach may include, among others, preparation for use or the use of methods or means of warfare that result in damage to objects that release GHGs, or in direct destruction of carbon sinks, such as forests, and the marine environment. Such acts are foreseeable, measurable, and attributable, given the established scientific and operational capacity to distinguish between routine or non-routine releases of emissions and to assess the absorptive functions and capacities of carbon sinks (here, here, and here). To qualify as breaches, the exercise of the latter acts must fall short of the applicable customary or treaty standards of feasible precaution in avoiding the attack, and in the event of attack, minimizing its incidental damage to the components of the climate system (Rule 44). This presents only one scenario under a single rule from multiple scenarios that may arise in relation to a variety of dispositions.  

Any case-by-case assessment of the actionability of a climate reparations claim will, evidently, extend beyond the test of the establishment of breach. The list of relevant legal issues may include, inter alia, questions of attribution and causality, the scope of potential claimants (e.g., primary belligerent victim, states with common interest), the nature of the damage sustained (cumulative vs. non-cumulative, significant vs. non-significant), the choice of appropriate forum, and the form of reparation. Of these, the last general issue warranting further consideration here is the choice of the forum.

Securing access to a forum with jurisdiction over wartime climate reparation claims is likely to present a considerable challenge. While the International Court of Justice is, in principle, well placed to adjudicate such disputes, it is most likely to be seized where its compulsory jurisdiction is accepted by the belligerent states under Article 36, paragraphs 2-5 of the Statute. For example, in the ongoing Iran, Israel and the US conflict, Iran is the only state with a relevant declaration. The likelihood of the Court entertaining a dispute between parties to AP I, for example, is also quite limited, as the instrument does not confer jurisdiction upon the Court in treaty matters, and the prospect of a special agreement or of an ad hoc consent from a respondent state appears remote,  thus far, albeit not impossible. In this context, a mention must be made also of the International Fact-Finding Commission under AP I, which is not a remedial mechanism, although it may still serve as an inquiry body to establish relevant facts and potential breaches.

As far as the European Court of Human Rights (ECtHR) and Inter-American Court of Human Rights (IACHR) are concerned, although both may entertain inter-State applications, and the former also individual complaints, their jurisdictional reach in the context of current conflicts is virtually none (here and here). The  available avenues for claims are not, of course, limited to the forums identified here, state practice suggesting that ad hoc mechanism may constitute a particularly  suitable option, where appropriate, with the  involvement of the United Nations Security Council (here, here, and here).  

Concluding Remark

The argument advanced in this piece is deliberately bounded. It does not claim that every act of warfare that generates greenhouse gas emissions constitutes an internationally wrongful act, or that climate reparations claims are straightforwardly actionable before existing international tribunals. What this post does establish is the legal architecture for such claims, whose components are stronger than their limited use to date might suggest. The customary duty to prevent significant harm to the climate system applies to all belligerents, irrespective of their treaty commitments. IHL’s conduct-of-hostilities rules apply to the climate system as a functional component of the natural environment, without requiring reliance on the contested cumulative threshold under Articles 35(3) and 55(1) of the AP I. And the law of state responsibility stands ready to convert breach into obligation. The question is no longer whether climate damage caused by unlawful force is a cognisable legal injury. The ICJ has answered that. The question now is who builds the case, and before whom.

Photo attribution: by Matt Palmer on Unsplash