IHL in the era of climate change: The application of the UN climate change regime to belligerent occupations

Abstract

This article invites the reader on a journey through the legal arguments that would confirm the application of the United Nations (UN) climate change regime to belligerent occupations. Although the regime is silent on this issue, its application should not be limited to peacetime due to the seriousness of global climate change and its adverse effects on the environment and living entities. A harmonious interpretation and application of the UN climate change regime and the law of occupation would allow Occupying Powers to ensure the safety and well-being of the civilian population and contribute to the protection of the Earth's climate system.

Once, a knight was riding back to his castle when he saw a little sparrow lying on its back in the middle of the road, with its small legs up in the air. Reining in his mount, the knight looked down and asked: “Why are you lying upside-down like that?” “I heard that the heavens are going to fall today,” replied the bird. The horseman laughed and asked: “And do you think that your spindly legs can hold up the heavens?” “Well,” replied the sparrow, “one does what one can.”

Antonio Cassese¹

Introduction

The emission of greenhouse gases (GHGs) into the atmosphere by human activities has decisively caused a rise in the Earth's temperature, a phenomenon known as anthropogenic climate change.² Due to the serious threat that climate change represents for the planet and the survival of living entities, States have decided to coordinate their action to stabilize and reduce the emission of GHGs by adopting the 1992 United Nations Framework Convention on Climate Change (UNFCCC),³ the 1997 Kyoto Protocol⁴ and the 2015 Paris Agreement,⁵ collectively referred to herein as the UN climate change regime. Despite climate change having an unusual macro scope and requiring a highly intense, permanent and long-term international cooperation, the treaties regulating this subject matter have a common feature: they are silent about their application during armed conflicts. This legal gap may give rise to uncertainties as to whether States Parties must respect the UN climate change regime during armed conflicts and, if so, how the rules and principles of international humanitarian law (IHL) should be interpreted and applied in an era in which climate change has become an international priority at all times.

This legal context is particularly relevant in the case of belligerent occupations, which are regulated by IHL. As is well known, these are – at least a priori – temporary situations, and the Occupying Power does not acquire sovereign rights over the occupied territory.⁶ Due to this temporality, occupations are governed by the general principle of preservation of the status quo ante bellum, according to which the Occupying Power can only adopt those measures that are necessary to restore and ensure public order and safety.⁷ As explained by Orkin and Ferraro, an Occupying Power must not adopt policies or measures that would introduce or result in permanent changes⁸ because one of the aims of the occupation regime is to facilitate transition and restoration of power to the legitimate authorities. It is worth recalling that occupations are ruled by conventional rules, including the 1907 Hague Convention IV with Respect to the Laws and Customs of War on Land and Its Annex (Hague Convention IV),⁹ the 1949 Geneva Convention IV relative to the Protection of Civilian Persons in Time of War (GC IV),¹⁰ and the 1977 Additional Protocol I to the Geneva Conventions.¹¹ IHL also contains customary norms applicable to such situations.¹²

This set of regulations is what has been called the “law of occupation”, and it was adopted and developed at a time when climate change did not exist, or at least was not yet publicly acknowledged as a global problem. Hence, the law of occupation has no specific rules related to how to deal with climate change in that concrete context. This raises questions regarding, first, the current scope of application of the law of occupation and the UN climate change regime, and second, how both legal regimes interact.¹³ The issue here is the tension that exists between the temporary nature of belligerent occupations and the permanent and global nature of climate change. In this context, due to the seriousness of global climate change and the humanitarian situation faced by the civilian population during a belligerent occupation, it is necessary to reflect on the compatibility between these two international legal regimes. With that in mind, the purpose of this essay is to address the scope of application of the UN climate change regime and to determine whether it is applicable during armed conflicts and in concrete, belligerent occupations.

The thesis presented in this essay is that the UN climate change regime applies permanently regardless of the context (peacetime or wartime). Firstly, this is because the suspension of its application due to armed conflicts (or, in this case, a belligerent occupation) would diminish the efficacy of this legal regime and could be catastrophic for the Earth's climate system and living entities. The seriousness and permanent characteristic of the climate change problem requires that all parties to the regime constantly take action to limit temperature increases to 1.5°C above pre-industrial levels, and the temporality of a belligerent occupation cannot be an excuse for not respecting and implementing the regime in the occupied territory. Secondly, from a humanitarian perspective, the safety of the civilian population of the occupied territory is simultaneously threatened by two sources: climate change and the occupation. Hence, the population must be protected from the negative consequences of both threats and should therefore benefit from the protection of both legal regimes.

In light of the above, four main legal arguments are developed to justify the application of the UN climate change regime to belligerent occupations. The first argument concerns respect for the UN climate change regime by Occupying Powers when that regime is part of the laws in force in the occupied territory. The second relates to the extraterritorial application of the regime in the occupied territory as a consequence of the “GHG production-based system boundary” adopted by the regime and the harm prevention principle recognized in international environmental law (IEL). The third argument is based on the principle of legal stability and continuity of treaties developed by the International Law Commission (ILC) in its Draft Articles on the Effects of Armed Conflicts on Treaties (ILC Draft Articles),¹⁴ and the application of the principle to the UN climate change regime. And finally, the application of the UN climate change regime during belligerent occupations is legally possible due to the connection between this regime and international human rights law (IHRL), and the obligation of the Occupying Power to respect and guarantee the recognized human rights of the civilian population under its effective control, in particular those rights affected by the adverse effects of climate change.

The importance of clarifying the scope of application of the UN climate change regime

The UN General Assembly has recognized that climate change is a common concern of humanity, since climate is an essential condition which sustains life on Earth.¹⁵ The serious threat that climate change represents for the planet and living entities has mobilized international public opinion and has brought the issue to the attention of the whole world. In this regard, it has been said that climate change is a “civilizational wake-up call … telling us we need to evolve”,¹⁶ and that we are “the last generation that can do something about it”.¹⁷ It has also been considered to be “the defining issue of our times”, and one that “presents a golden opportunity to promote prosperity, security and a brighter future for all”.¹⁸ Hulme believes that climate change is not just another international problem waiting for a solution; instead, he believes that it is “an environmental, cultural and political phenomenon which is reshaping the way we think about ourselves, about our societies and about humanity's place on Earth”.¹⁹

Due to the global character, complexity and scientific uncertainties of climate change, from a legal perspective it was necessary to adopt a flexible international regime that would be easily adapted to the fluctuations of the phenomenon and the advances of science. The UN climate change regime follows the framework convention–protocol approach,²⁰ in which the UNFCCC establishes the legal structure for addressing climate change – objectives, principles and institutional architecture – and the protocols specify the concrete action that should be taken to achieve the objectives. For that reason, the UNFCCC is considered a living instrument as it is capable of evolving and responding to the scientific realities of climate change,²¹ through the conclusion of complementary treaties.

In this sense, the complementarity between the UNFCCC and the Paris Agreement can also be observed in their objectives. The UNFCCC's Article 1 states that the ultimate objective of the Convention and future protocols – the long-term global goal – is to achieve the stabilization of GHG concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. That level is specified in Article 2 of the Paris Agreement: the increase in the global average temperature must be held to well below 2°C above pre-industrial levels, and parties must make efforts towards limiting the temperature increase to 1.5°C above pre-industrial levels.

As mentioned before, the final provisions of both legal instruments are silent about their application during armed conflicts.²² In the case of the Paris Agreement, Voigt explains that the Durban Mandate (established at the 17th Conference of the Parties, in 2011) outlined several topics which were to become part of the work of the working group for drafting the new agreement, but the institutional provisions and final clauses were not explicitly mentioned in that mandate, and negotiations about them started later.²³

The ILC's Draft Principles on the Protection of the Environment in Relation to Armed Conflicts (ILC Draft Principles)²⁴ are a necessary starting point for elucidating the scope of application of the UN climate change regime. The Draft Principles are applicable before, during and after an armed conflict, including in situations of occupation (Draft Principle 1). Furthermore, Draft Principle 13 establishes the general rule that the environment shall be respected and protected in accordance with applicable international law, in particular the law of armed conflicts. This proposed rule is coherent with the content of Draft Principle 19 on the “General Environmental Obligations of an Occupying Power”, which also specifies that an Occupying Power shall take environmental considerations into account in the administration of a territory.²⁵ In the Commentaries, the ILC clarifies that the phrase “applicable international law” in Draft Principles 13 and 19 refers to the law of armed conflict, but also to IEL²⁶ and IHRL.²⁷ As for the application of IEL in situations of armed conflict, the ILC considers that the claim that customary and conventional IEL continue to apply during such situations can be supported by the interpretation provided by the International Court of Justice (ICJ) in its Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons (Nuclear Weapons Advisory Opinion), and by the ILC Draft Articles on the Effects of Armed Conflicts on Treaties.

Regarding the Nuclear Weapons Advisory Opinion, on that occasion the ICJ made an important authoritative statement on international environmental obligations and the interests of future generations.²⁸ Nevertheless, it also observed that it could not “reach a definitive conclusion as to the legality or illegality of the use of nuclear weapons by a State in an extreme circumstance of self-defence, in which its very survival would be at stake”.²⁹ The Advisory Opinion thus illustrates how in that moment, the protection of the environment was marginalized to favour sovereign security interests despite the evident and proven environmental destructiveness of nuclear weapons.³⁰ Therefore, this historic and international legal precedent raises the question of whether the seriousness of the global climate change problem is itself enough to presume or take for granted the application of the UN climate change regime during armed conflicts. The answer is negative. Thus, due to the interests at stake, and with the aim of avoiding States party to the regime excusing themselves from complying with it during armed conflicts due to national security reasons and of avoiding possible similar legal results before domestic or international courts, more legal arguments should be developed to support ILC Draft Principles 13 and 19 regarding the application of the UN climate change regime to belligerent occupations, so that States’ security interests are not privileged over the protection of the environment and the civilian population. While they are an authoritative legal instrument, the ILC Draft Principles are per se a soft-law instrument and are therefore not in force.

In this regard, one should be mindful of the fact that in general any armed conflict threatens the security of belligerent parties and that the “carbon bootprint”³¹ of the concerned States, or their GHG emissions, usually skyrockets during armed conflicts.³² It thus follows that to protect current and future generations from the negative impacts of climate change, it is crucial to determine whether the UN climate change regime is applicable regardless of the factual context (peace or war), with the aim of avoiding States invoking national security interests to argue that the regime is only applicable during peacetime.³³ This legal determination is particularly important in the case of belligerent occupations because, as clearly pointed out by Spoerri, occupation law's prescriptions are frequently interpreted by the Occupying Power in a self-serving manner in order to reduce constraints on their discretionary powers.³⁴ Finally, it is worth mentioning that even if nowadays belligerent occupations are few in number compared with the number of international and non-international armed conflicts taking place,³⁵ GHG emissions from occupied territories have an impact on Earth's climate system, and climate change could also negatively affect those territories and their civilian populations. Thus, the scarcity of occupied territories in the world should not be used as an excuse for failing to apply the UN climate change regime in such territories. Just as the sparrow says to the knight in Cassese's tale, “one does what one can”, so too do all States Parties share a common responsibility to address global climate change in all circumstances, including situations of occupation.

On why the UN climate change regime is applicable to belligerent occupations

Having clarified the importance of determining the scope of application of the UN climate change regime, the next step is to examine the legal arguments that would help us to make that determination. With the aim of presenting and explaining the arguments in a didactic manner, this article proposes to assess the issue through the lens of a theoretical “legal maps app” (similar to Google Maps) that guides legal experts and practitioners to arrive at their legal destination, which is the permanent application of the UN climate change regime, particularly during belligerent occupations.

Like any digital map application, this “legal maps app” has a departure point for our journey. That departure point is Principles 23 and 24 of the 1992 Rio Declaration on Environment and Development,³⁶ because these principles operate as a “legal umbrella” that guides the conduct of States on the protection of the environment during armed conflicts. Based on the general principle of pacta sunt servanda (Article 26 of the Vienna Convention on the Law of Treaties (VCLT)),³⁷ the unanimously adopted Principle 24 asserts the application of all those relevant international rules – conventional, customary and general principles of law – that provide protection to the environment during armed conflicts³⁸ (without differentiating between international and non-international armed conflicts).³⁹ Principle 23, meanwhile, reaffirms the protection against environmental risks faced by people under oppression, domination and occupation.⁴⁰

Our “legal maps app” envisages four alternative routes towards the chosen destination (i.e., the permanent application of the UN climate change regime), all determined according to their time frame, and these will be analyzed in the following subsections. The short-term road examines whether or not the phrase “laws in force” in Article 43 of Hague Convention IV comprehends the UN climate change regime when the Occupied State is party to it. The first mid-term road concerns the possible extraterritorial application of the UN climate change regime in the occupied territory, while the second mid-term road is based on the application of the principle of legal stability and continuity of treaties during armed conflicts to the UN climate change regime. Finally, the long-term road relates to the interaction between IHL, the UN climate change regime and IHRL during belligerent occupations.

The short-term road: The UN climate change regime and the laws in force in the occupied territory

As a branch of IHL, the law of occupation tries to find a balance between the interests of the Occupying Power, the interests of the legitimate authorities of the occupied territory, and the well-being of the local population.⁴¹ It establishes two core obligations of conduct for Occupying Powers that are interconnected. On the one hand, they must restore and maintain public order and civil life in the occupied territory (including the welfare of the population); on the other hand, they must respect (unless absolutely prevented from doing so) the laws in force in the occupied territory (Article 43 of Hague Convention IV and Article 64 of GC IV).

Article 43 of Hague Convention IV can be thought of as a door left ajar, through which the UN climate change regime can enter and start interacting with the law of occupation, providing that the phrase “laws in force” from Article 43 is broadly interpreted.⁴² In this regard, Sassòli proposes a broad conception of the phrase and considers that it refers to the entire legal system of the occupied territory.⁴³ This means that it includes constitutions, decrees and ordinances, executive orders, national and municipal laws, and substantive and procedural law.⁴⁴ However, it is worth remembering that a State's legal system consists of its domestic laws as well as those international customary and conventional rules in force and binding upon it (whose internal incorporation will depend on the monist or dualist system of law adopted by a State). Consequently, it can be affirmed that international legal rules in force for the Occupied State are included in the phrase “laws in force” found in Article 43, and that these rules are a source of obligations for the Occupying Power⁴⁵ because, as the de facto authority effectively controlling the territory (even a part of it), it is responsible for complying with them,⁴⁶ particularly those that would help to ensure the maintenance of public order and safety in the occupied territory.

The UN climate change regime is a good example of international binding rules that can help to ensure the maintenance of public order and safety in the occupied territory because the implementation of that regime, through the adoption of mitigation and adaptation measures by the Occupying Power, would tend to reduce the civil population's vulnerability to climate change⁴⁷ and thereby help to maintain a healthy – local and global – environment for the enjoyment of human rights. Moreover, it would also contribute to keeping safe the Occupying Power's armed forces deployed in the occupied territory. Therefore, respect for the UN climate change regime and the application of that regime to belligerent occupations are beneficial for all the parties affected by an armed conflict as well as for the Earth's climate system. In other words, from a humanitarian and environmental perspective, a broad interpretation of Article 43 of Hague Convention IV is needed because today's reality demands that Occupying Powers take action against climate change, as their inaction (or lack of adoption of adequate measures) could have a negative impact on the Earth's climate system, the local natural environment, and human beings – temporal and permanent – living in the occupied territory.

The first mid-term road: The extraterritorial application of the UN climate change regime to belligerent occupations

According to the information available at the UN Treaty Collection, the UNFCCC has been ratified by 198 States,⁴⁸ and the Paris Agreement by 195 States.⁴⁹ In the hypothetical case that only the Occupying Power is party to the UN climate change regime – because the occupied State never expressed its consent or because it decided to withdraw from it⁵⁰ – the Occupying Power will have to respect the regime in the occupied territory based on the “GHG production-based system boundary” implemented by the UN climate change regime. This system boundary has a territorial approach according to which GHG emissions are allocated to the State Party in whose territory they are generated,⁵¹ so that it can stabilize and reduce them by exercising its sovereign powers. A concrete example of this criterion is the obligation of States party to the Paris Agreement to submit every five years their domestic plans for climate action, known as “nationally determined contributions” (Article 3).⁵²

The said obligation could be interpreted in a restrictive manner as covering only those emissions produced in the metropolitan territories of the parties (in this case, Occupying Powers). However, the implementation of this obligation should be done through the spirit of the harm prevention principle, as the UN climate change regime is part of IEL.⁵³ The harm prevention principle is considered the cornerstone⁵⁴ or the raison d’être of IEL;⁵⁵ it reflects a rule of customary nature;⁵⁶ it is included in paragraph 8 of the preamble to the UNFCCC; and its application during belligerent occupations is also proposed in ILC Draft Principles 19.2 and 21.⁵⁷ According to the harm prevention principle, a State has the responsibility to ensure that activities within its jurisdiction or control do not cause damage to the environment of other States or of areas beyond the limits of its national jurisdiction.⁵⁸ The ICJ has interpreted that the harm prevention principle has a due-diligence nature, meaning that States are obliged to use all means at their disposal to avoid environmental harm.⁵⁹

The notion of “jurisdiction or control” over a space is a key component of the harm prevention principle because it connects the concerned State with the environment of that space and its protection. Coincidentally, the notion of “control” is also important in the law of occupation⁶⁰ because according to Article 42 of Hague Convention IV, a territory is considered occupied when “it is actually placed under the authority of the hostile army”.⁶¹ As explained by Vité, two conditions must be fulfilled for occupation to exist: (1) the Occupying Power is able to exercise effective control over a territory that does not belong to it, assuming this status when its troops are deployed in the concerned territory and it is in a position to exercise its own power; and (2) its intervention has not been approved by the legitimate sovereign (even if there is no armed resistance).⁶² Consequently, there is a connection between the harm prevention principle and the law of occupation through the notion of “control”.

A harmonic interpretation and application of the Paris Agreement and the harm prevention principle in a context of belligerent occupation would therefore allow us to conclude that the Paris Agreement should be applied in an extraterritorial manner to those areas under the jurisdiction or control of States Parties, such as in the case of occupied territories. Accordingly, the Occupying Power would be responsible for controlling GHG emissions from the occupied territory under its effective control (in order to avoid worsening the climate change situation), should take concrete actions to mitigate those GHG emissions and to protect the civil population from climate change during the occupation, and should include in its nationally determined contributions those GHGs produced in the occupied territory when that space is under its effective control.⁶³

The second mid-term road: The principle of legal stability and continuity of treaties and the UN climate change regime

Another route that the “legal maps app” offers to arrive at our destination point is related to the principle of legal stability and continuity of treaties. According to this principle, it is presumed that the existence of an armed conflict does not ipso facto terminate and suspend the operation of a treaty, as proposed by ILC Draft Article 3.⁶⁴ When the concerned treaty does not contain provisions on its operation in situations of armed conflict, in Draft Article 6, the ILC has proposed a non-exhaustive list of factors that could serve to determine the susceptibility to termination, suspension or withdrawal of a treaty, which may or may not be relevant for it depending on the circumstances.⁶⁵ Subparagraph (a) focuses on those factors in relation to the treaty itself, while subparagraph (b) deals with those related to the characteristics of the armed conflict.

According to Draft Article 6, the treaty-related factors that could be considered for the determination are the nature of the treaty (in particular, its subject matter), its object and purpose, its content, and the number of parties to the treaty.⁶⁶ Subparagraph (a) is linked to Draft Article 7, which proposes an indicative list (found in the Annex) of categories of treaties whose subject matter involves an implication that they continue in operation during armed conflicts.⁶⁷ The ILC recognizes that in certain cases, the proposed categories are overlapping.⁶⁸ The categories included in the list that are relevant for the purposes of this paper are the ones related to “treaties declaring, creating or regulating a permanent regime or status or related permanent rights” (Annex, subparagraph (b)) and “treaties relating to the international protection of the environment” (Annex, subparagraph (g)).

Based on the treaty-related factors included in Draft Article 6(a), from the content of the UNFCCC and the Paris Agreement, as well as considering the number of States Parties they have, it can be inferred that both legal instruments are multilateral treaties related to the protection of the environment, open to consent by any State or regional economic integration organizations, and they have achieved almost universal ratification. Besides this, the general subject matter (the protection of the environment) and the objective (the stabilization of GHG concentrations in the atmosphere) of this legal regime are connected to the magnitude, duration, seriousness and uncertainties of climate change. It is precisely due to these characteristics of the climate change problem that those treaties have established a permanent regime with the aim of enabling States Parties to take constant collective action in order to tackle the problem effectively, because this issue will affect humanity for several generations. As highlighted by Thorgeirsson, the UNFCCC is in essence a planetary risk-management treaty,⁶⁹ and this feature can be extended to the entire regime. Furthermore, this special feature of the UN climate change regime – as an environmental permanent regime (following Draft Article 7's criteria) – can also be inferred from the preamble of the UNFCCC, in which the States Parties acknowledge that climate change is a problem surrounded by uncertainties with regard to timing, magnitude and regional patterns (paragraph 5), and that they are determined to protect the climate system for present and future generations (paragraph 23) because the global nature of the climate change problem and its adverse effects are a common concern of humankind (paragraph 1).

The permanent application of the UN climate change regime can also be inferred from the fact that the regime has been established to deal with a global environmental problem. Besides this, with the aim of stabilizing GHG concentrations in the atmosphere and achieving “net zero”, the regime intends to modify collective and individual behaviour connected to patterns of production and consumption, and this transition will take decades. Moreover, it can be considered that the regime seeks to serve the interests of the international community as a whole by having as its primary objective the protection of a common environmental good⁷⁰ (the climate system), as well as the protection of human health, safety and life on Earth for present and future generations. Consequently, considering that Earth's climate system is a common concern of humankind, the permanent application of the regime can be confirmed as it plays a critical legal role in addressing the problem. Finally, the regime's permanent application is necessary as a way of maximizing the effectiveness of the regime and the efforts made so far to cope with the climate problem.

As for the armed conflict-related factors listed in ILC Draft Article 6(b), these include the territorial extent of the armed conflict, its scale and intensity, its duration and, in the case of non-international armed conflicts, the degree of outside involvement. The duration factor is key in the determination of the continuous application of the UN climate change regime because of an intrinsic characteristic of belligerent occupations: they are supposed to be temporary situations because it is expected that the legitimate authorities will return to power soon.⁷¹ However, this temporality should not be an excuse for precluding the application of the UN climate change regime during this type of armed conflict. This is because the essence of the law of occupation is to find a balance between, on the one hand, the protection of the life and property of inhabitants (included the local environment) as well as respect for the sovereign rights of the ousted government;⁷² and, on the other hand, the fulfilment of the security and military needs of the Occupying Power.⁷³ It is precisely the protection of life and the environment of the occupied territory that triggers the necessity of applying the UN climate change regime during belligerent occupations in order to reduce the adverse effects of climate change in the occupied territory. In other words, the UN climate change regime has to be applied during belligerent occupations for humanitarian and environmental reasons, and even more so in case of prolonged occupations.⁷⁴ Therefore, the negative impact of climate change on the civilian population⁷⁵ and the environment, and the lack of action by the Occupying Power in reducing GHG emissions in the occupied territory, as well as in adopting mitigation and adaptation measures to reduce and prevent those climate consequences, would be contrary to the object and purpose of the UN climate change regime – including the harm prevention principle – and the humanitarian spirit of the law of occupation.

The foregoing analysis, based on ILC Draft Article 6 and subparagraphs (b) and (g) of the Annex related to ILC Draft Article 7, allows us to conclude that the intrinsic characteristics of the UN climate change regime explained above, as well as the well-known negative consequences that climate change is having on the environment itself and on humanity, are enough to justify the permanent application of the regime regardless of the context (peacetime or wartime), because the regime's interrupted application or suspension due to armed conflict can be catastrophic in general for Earth's climate system and in particular for the civilian population affected by the armed conflict. As mentioned by the ILC, in the case of environmental treaties that are widely ratified and that have a global scope, it may be difficult to conceive of the suspension of those treaties exclusively between the parties to the armed conflict, because “obligations established under such treaties protect a collective interest and are owed to a wider group of States than the ones involved in the conflict or occupation”.⁷⁶

The long-term road: The holistic application of IHL, IHRL and the UN climate change regime during belligerent occupations

Finally, the fourth route offered by the “legal maps app” concerns the relationship between and application of IHL, IHRL and the UN climate change regime during belligerent occupations. It is introduced as the “long-term road” because the question of how these three branches of public international law interact does not have a definitive answer yet. For instance, the ILC, in its study on Fragmentation of International Law,⁷⁷ considers that the principle of systemic integration (Article 31(3)(c) of the VCLT) is the key tool to be used for interpreting and determining the relationship between general international norms and norms of self-contained regimes, in order to maintain the coherence of public international law. However, the ILC concludes that the VCLT alone is not enough to give an answer to the emergence of conflicting rules and overlapping legal regimes, because it does not give sufficient recognition to special types of treaties and the special rules that may be useful for their application and interpretation. Finally, the ILC concludes that the whole complex of inter-regime relations is a legal black hole, and wonders what principles of conflict solution might be used for dealing with conflicts between two regimes or between instruments across regimes. In this regard, the ILC Draft Principles provide an answer to the applicability of other international legal regimes that protect the environment during armed conflicts, besides IHL. Yet, in the Draft Principles, the ILC does not propose how that interaction and application should take place or the criteria for resolving possible normative contradictions between IHL, IHRL and IEL, this being left to the consideration of States and stakeholders.

As for the application of IHRL during armed conflicts,⁷⁸ the ICJ has confirmed that “the protection offered by human rights conventions does not cease in case of armed conflict”, and has also affirmed that the 1966 International Covenants on Civil and Political Rights and on Economic, Social and Cultural Rights are applicable in respect of acts carried out by a State in the exercise of its jurisdiction outside its own territory, particularly in occupied territories, confirming the extraterritorial application of the Covenants.⁷⁹ This interpretation is emblematic because it has opened the door for other international legal regimes, like IHRL, to contribute to and strengthen the humanitarian and legal protections provided during armed conflicts, in particular in situations of belligerent occupation.⁸⁰

This opened door is an interesting one to be crossed by IHRL hand in hand with the UN climate change regime (as part of IEL), with the aim of providing humanitarian protection to civilian populations simultaneously affected by armed conflict (in this case, belligerent occupation) and the adverse effects of climate change. For instance, the Paris Agreement's preamble expressly connects the UN climate change regime and IHRL by acknowledging that States Parties should – when taking action to address climate change – respect, promote and consider their respective obligations on human rights (paragraph 11). Carazo highlights that this acknowledgement is important because the Paris Agreement is the first multilateral environmental agreement to incorporate express reference to human rights, this being considered as revolutionary.⁸¹

The express connection between the two regimes is a legal advantage that must be seized, and its implementation during belligerent occupations can take place in two ways. Firstly, it can take place through the intimate interlink between the climate change crisis and the enjoyment of recognized human rights. There are several fundamental human rights that are already being affected across the planet – like the rights to life, to health, and to food and water – as a consequence of climate change and the lack or inadequacy of policy action from governments.⁸² Secondly, it could take place through the international (and domestic) recognition of the human right to a safe, clean, healthy and sustainable environment. This recognition is important because it enhances “the enjoyment of rights holders, and the accountability of duty bearers to respect, protect and fulfil this right”.⁸³ Legal action on this issue has been taken by States,⁸⁴ international organizations and international tribunals. For instance, the UN Human Rights Council⁸⁵ and UN General Assembly⁸⁶ have expressly recognized the right to a healthy environment as a human right that is important for the enjoyment of other human rights, that is related to other rights and existing international law, and whose promotion requires the full implementation of multilateral environmental agreements under the principles of IEL. Besides this, Article 24 of the African Charter on Human and Peoples’ Rights recognizes the right to a general satisfactory environment.⁸⁷ Furthermore, when the Inter-American Court of Human Rights had the first opportunity to analyze States’ obligations arising from the need to protect the environment under the American Convention on Human Rights, it considered that

the right to a healthy environment is recognized explicitly in the domestic laws of several States of the region, as well as in some provisions of the international corpus iuris …. The human right to a healthy environment has been understood as a right that has both individual and also collective connotations. In its collective dimension, the right to a healthy environment constitutes a universal value that is owed to both present and future generations. That said, the right to a healthy environment also has an individual dimension insofar as its violation may have a direct and an indirect impact on the individual owing to its connectivity to other rights, such as the rights to health, personal integrity, and life. Environmental degradation may cause irreparable harm to human beings; thus, a healthy environment is a fundamental right for the existence of humankind.⁸⁸

Consequently, either because of the intimate connection between climate change and adverse effects on basic human rights or because of the consecration of the human right to a healthy environment as a right in itself, Occupying Powers will have to apply IHRL and the UN climate change regime in the occupied territory under their effective control because they are obliged to respect and adopt appropriate measures to protect those basic and recognized human rights of the civilian population⁸⁹ whose enjoyment can be affected or worsened due to the effects of climate change in the occupied territory.⁹⁰ Occupying Powers will have to adapt to governance challenges,⁹¹ as the exercise of jurisdiction or control over a territory does not come without responsibilities. Lastly, an immediate legal consequence of the connection between the UN climate change regime and IHRL would be the constant respect and application of the UN climate change regime regardless of the context.⁹²

Conclusions

Current belligerent occupations are taking place in a context of global climate change, a problem that represents a challenge for the civilian populations of occupied territories simultaneously affected by the adverse consequences of it and by the armed conflict. IHL is silent about belligerent parties’ duties regarding climate change, and the UN climate change regime is silent about its application in situations of armed conflict. Nevertheless, as clearly highlighted by Slade, silence from the UN climate change regime on the links between armed conflict and climate does not mean silence from IHL, in particular, because both legal regimes share the same humanitarian concern towards the well-being of people.⁹³ Global climate change does not distinguish between peacetime and times of armed conflict, as the application of public international law does; it is simply happening, and it is happening constantly. Therefore, both legal regimes – together with IHRL – can be applied in a complementary manner so that Occupying Powers can take action against the adverse effects of climate change in order to maintain the safety and well-being of the civilian populations of occupied territories and to contribute to the protection of Earth's climate system. The application of the UN climate change regime should not be limited to peacetime and should remain in force during armed conflicts, including belligerent occupations, due to humanitarian and environmental reasons. Regrettably, IHL is “sometimes charged with being a war behind”.⁹⁴ Hence, in order to keep IHL updated and able to tackle climate change during belligerent occupations, it is necessary to take into account environmental considerations when interpreting the law of occupation, with a view to establishing the permanent application of the UN climate change regime regardless of the context. This is the global and legal momentum for interpreting the law of occupation in light of environmental considerations so that it can be well suited to contemporary challenges.