3.1 Introduction

Stratospheric ozone, or ozone in the stratospheric layer of the atmosphere, plays a crucial role in absorbing the sun’s ultraviolet (UV) radiation. Destruction of stratospheric ozone allows UV radiation, primarily UV-B, to reach the Earth’s surface. Excessive UV-B radiation can cause skin cancer and cataracts in humans, stunting in plants, and harm to animals integral to the marine food chain (Nanda Reference Nanda1989: 489–90). In recognition of the severe and irreversible effects of UV-B radiation on human health and ecosystems, Rockström and colleagues identified stratospheric ozone depletion as one of the nine planetary boundaries (Rockström et al. Reference Rockström, Steffen and Noone2009a, Reference Rockström, Steffen and Noone2009b; see also: Steffen et al. Reference Steffen, Richardson and Rockström2015).

Stratospheric ozone depletion is one of the few planetary boundaries for which a relevant international law regime – consisting of the Vienna Convention for the Protection of the Ozone Layer (1985) and the Montreal Protocol on Substances that Deplete the Ozone Layer (1987)Footnote ¹ – is readily identifiable; and it is widely considered to be one of the most effective international environmental law (IEL) regimes to date. However, the implementation of the ozone regime has had the effect of shifting problems (Kim & van Asselt Reference Kim, van Asselt, Morgera and Kulovesi2016), thereby creating new, unregulated problems. Furthermore, based as it is on principles such as the principle of sustainable development and the principle of permanent sovereignty over natural resources, the ozone regime is human-centred, and concern for the protection of ozone is arguably linked to its value to humans. While several concerns discussed in this chapter could potentially be addressed by ‘tinkering at the margins’ (Kotzé Reference Kotzé2020: 77), this would not address the underlying values and principles of the ozone regime (which underlie international environmental law more generally: see, e.g., Garver Reference Garver2019; Kotzé & Kim Reference Kotzé and Kim2019; Kotzé et al. Reference Kotzé, Du Toit and French2020); and it is argued in this chapter that broader shifts are required in order to be able to respond the types of challenges being faced in the Anthropocene (Crutzen & Stoermer Reference Crutzen and Stoermer2000; Steffen et al. Reference Steffen, Crutzen and McNeill2007), a new geological epoch, in which humans have become ‘geological agents’ (Oreskes Reference Oreskes, Dimento and Doughman2007: 93; see also Raworth Reference Raworth2014; Moore Reference Moore2016).

The chapter first briefly outlines the international law regime for ozone depletion. The section following highlights various socio-ecological impacts and injustices that arise from the implementation of the ozone regime. Thereafter, the chapter begins to explore how values underlying the ozone regime could potentially evolve in order to address these types of concerns and highlights the importance of shifting away from the human-centred and utilitarian values that underlie the ozone regime and IEL more generally.

3.2 The International Regulation of Stratospheric Ozone Depletion

Chlorofluorocarbons (CFCs) were invented in 1928 as a safer (non-toxic) and more stable alternative to other substances, such as sulphur dioxide and ammonia, for use as home refrigerants (Sinclair Reference Sinclair, Andersen and Sarma2002: 4).Footnote ² Their use on a large scale began in the 1930s (Goyal et al. Reference Goyal, England, Sen Gupta and Jucker2019: 1), and, by 1985, total CFC production exceeded one million tonnes. Of note, per capita consumption of CFCs was 10 times greater in developed countries than in developing countries (Gillespie Reference Gillespie2006: 21). While there was growing concern regarding the increasing presence of CFCs in the atmosphere and their potential role in depleting stratospheric ozone (Molina & Rowland Reference Molina and Rowland1974), there was also considerable uncertainty throughout the 1970s and early 1980s regarding the causes of ozone depletion (with many trying to attribute it to natural causes) as well as the risk that ozone-depleting substances (ODSs) actually posedFootnote ³ (DeSombre Reference DeSombre2000: 49). There was also disagreement over whether a precautionary approach should be followed, or whether conclusive evidence of ozone depletion should first be required (Gillespie Reference Gillespie2006: 152–57).

It was thus significant that the Vienna Convention was agreed to in March 1985. The negotiation process – with regard to both the Vienna Convention and the Montreal Protocol (agreed to two years later) – has been described as ‘particularly impressive’ since negotiations were carried out and agreement reached ‘under conditions of uncertainty, both over the existence and extent of environmental harm and the costliness of taking action to mitigate it’ (DeSombre Reference DeSombre2000: 49). Parties to the Vienna Convention, in the Preamble, noted the potentially harmful impact of the modification of the ozone layer on human health and the environment and indicated their determination to protect human health and the environment from adverse impacts resulting from such modification.

In 1987, the same year in which the link between CFCs and ozone depletion was conclusively established (Sinclair Reference Sinclair, Andersen and Sarma2002: 22), the Montreal Protocol was concluded. Parties more explicitly recognized that emissions of certain substances can deplete the ozone layer and they resolved to control the emission of such ODSs ‘with the ultimate objective of their elimination’ (Montreal Protocol: Preamble). Significantly, the Montreal Protocol introduced control measures for the phase-down of ODSs. Initially, only CFCs and halons were regulated by the Montreal Protocol as these were the only substances that had been identified as being ozone-depleting. However, over time, more substances were identified as being responsible for ozone depletion (Gillespie Reference Gillespie2006: 164; Roberts Reference Roberts2017: 221), and they were accordingly also brought under the control of the Montreal Protocol through several amendments (articles 2A–2J). The Montreal Protocol now covers 114 chemicals in 10 chemical groups, including hydrochlorofluorocarbons (HCFCs), carbon tetrachloride (CTC), and hydrofluorocarbons (HFCs); and it provides for the near-complete phase-out of the substances under its control.

These substances are used in various applications, including air conditioners, refrigerators, and fire extinguishers, and as aerosol propellants and fumigants (DCCEEW 2018). It is notable that many of the substances controlled under the Montreal Protocol are also powerful greenhouse gases and have global warming potentialsFootnote ⁴ (GWPs) hundreds to thousands of times greater than that of carbon dioxide (WMO 2018: Table A-1).

The ozone regime takes specific account of the special needs and circumstances of developing country parties (Vienna Convention, Preamble; Montreal Protocol, Preamble and article 5) and includes several mechanisms in this regard, including delayed compliance with the Montreal Protocol’s control measures (article 5(1) and article 5(8 bis)–article 5(8 qua)) and the allowance of a certain amount of production of controlled substances to ‘satisfy the basic domestic needs’ of developing country parties (articles 2D–2J). Furthermore, in 1990, the Montreal Protocol was amended to provide for the establishment of a financial transfer mechanism (article 10); and the Multilateral Fund – which provides funding to developing country parties to assist them in complying with their obligations under the Montreal Protocol – was established in 1991. This Fund is managed by an Executive Committee, which has equal numbers of Article 5 (developing) and non-Article 5 (developed) country parties. There is also a double majority voting system, in terms of which decisions require a two-thirds majority vote, which represents a majority amongst developed and developing country parties. On this basis, it has been argued that the Montreal Protocol has given effect to the principle of common but differentiated responsibilities (Gonzalez et al. Reference Gonzalez, Taddonio and Sherman2015: 124–25).

More generally, the Montreal Protocol is the first international treaty to have been universally ratified (Godin-Beekmann et al. Reference Godin-Beekmann, Newman and Petropavlovskikh2018: 331); and it has been highly effective in addressing its central concern. Indeed, it was described by former United Nations Secretary-General Kofi Annan (Environmental Investigation Agency 2017) as ‘[p]erhaps the single most successful international agreement to date’. Rockström et al. argue that ‘[o]n balance, the case of stratospheric ozone is a good example where concerted human effort and wise decision making seem to have enabled us to stay within a planetary boundary’ (Reference Rockström, Steffen and Noone2009a: 12). Nevertheless, the implementation of the ozone regime has given rise to several concerns, which are now turned to.

3.3 Concerns Arising from the Implementation of the Ozone Regime

First, and more narrowly, several concerns arise due to ‘gaps’ in the ozone regime (discussed in detail in Du Toit, Reference Du Toit, Kulovesi, Yamineva and Recio2023). For example, ‘production’ is defined so as to exclude controlled substances that are used entirely as feedstock to produce other chemicals (Montreal Protocol, article 1(5)). This means that harmful substances, such as CFCs and HCFCs, may continue to be produced in order to manufacture other substances, including plastics (Andersen et al. Reference Andersen, Gao and Carvalho2021), which are associated with their own adverse socio-ecological impacts (see, among many others, Galloway & Lewis Reference Galloway and Lewis2016; Azoulay et al. Reference Azoulay, Villa and Arellano2019; Hamilton et al. Reference Hamilton, Feit and Muffett2019; Whitchurch Reference Whitchurch2019; Revell et al. Reference Revell, Kuma, Le Ru, Somerville and Gaw2021).

Furthermore, the Montreal Protocol is focused on phasing out substances that are highly ozone-depleting, which are then replaced by substances that are less ozone-depleting – without regard being had to other adverse impacts. Indeed, ‘alternative substances’ are narrowly defined in the Vienna Convention as ‘substances which reduce, eliminate or avoid adverse effects on the ozone layer’ (article 1(4)). Following the phase-down of CFCs and HCFCs, the production and consumption of HFCs increased significantly (Roberts Reference Roberts2017: 224). While HFCs are largely not ozone-depleting, they are powerful greenhouse gases and some HFCs are thousands of times more powerful than carbon dioxide (WMO 2018: Table A-1). Increasing HFC emissions were therefore contributing to climate change. This was a classic example of problem shifting, which ‘occurs when a solution for one problem backfires and generates one or more new problems at different times or locations’ (Kim & van Asselt Reference Kim, van Asselt, Morgera and Kulovesi2016).

Significantly, in 2016, parties agreed to the addition of HFCs to the list of substances controlled by the Montreal Protocol (UNEP 2016). Consequently, HFCs are being replaced by other substances, including hydrofluoroolefins (HFOs), which while having low ozone-depleting potentialsFootnote ⁵ (ODPs) and low GWPs, degrade to produce trifluoroacetic acid (TFA) and ozone. TFA is a ‘persistent toxic chemical’ (Montzka and Velders Reference Montzka, Velders and Krummel2018: 2.4), and its presence has been detected in humans; plants, including crops consumed by humans; aquatic environments; and in the Arctic region (Pickard et al. Reference Pickard, Criscitiello and Persaud2020: 2). For its part, ozone is a greenhouse gas and pollutant at ground level and contributes to more than one million pollution-related (human) deaths per year. Ozone is also toxic to many plants and contributes to significant crop losses (Climate and Clean Air Coalition n.d.), which has implications for, at the very least, human health and well-being. While their long-term impacts are not yet clear (Montzka and Velders Reference Montzka, Velders and Krummel2018: 2.34), it has been argued that HFOs ‘cannot be regarded as overall sustainable alternatives’ (De Graaf et al. Reference De Graaf, Elsner and Hoffmann2021: 9). These examples demonstrate that there is the potential for problem shifting to arise again in the future. However, these new problems – created through the implementation of the ozone regime – would fall beyond the regulation of the ozone regime.

At a deeper level, various values and principles underlying the ozone regime specifically, and international law more broadly, are problematic, and possibly underpin the types of concerns identified earlier. It has been argued generally that international environmental law is incapable of responding to the types of socio-ecological crises that are being experienced in the Anthropocene, including because it is anthropocentric, and it does not embrace an earth system perspective (Kotzé & Kim Reference Kotzé and Kim2019, Reference Kotzé and Kim2021).

The ozone regime was established in the 1980s, and, while it has developed, it remains human-centred. Its concern, reflected throughout, is with humans first and then the environment. Furthermore, the Vienna Convention in its Preamble specifically recalls the ‘pertinent provisions’ of the Declaration of the United Nations Convention on the Human Environment (the Stockholm Declaration), particularly ‘principle 21, which provides that “States have, in accordance with the Charter of the United Nations and the principles of international law, the sovereign right to exploit their own resources pursuant to their own environmental policies”’. Although the principle of permanent sovereignty over natural resources is linked to decolonization and addressing the North–South divide (Atapattu Reference Atapattu, Alam, Atapattu, Gonzalez and Razzaque2015: 80), it clearly promotes the exploitation of natural resources (Kotzé et al. Reference Kotzé, Du Toit and French2020). More generally, the primary concern of the Stockholm Declaration is with preserving the ‘human environment’ due to its utility to humans and it does not recognize the intrinsic value of nature. The Declaration emphasizes that ‘[e]conomic and social development is essential for ensuring a favourable living and working environment for man and for creating conditions on earth that are necessary for the improvement of the quality of life’ (United Nations 1972: principle 8) and, furthermore, that ‘[o]f all things in the world, people are the most precious’ (United Nations 1972: Preamble). The Stockholm Declaration is clearly focused on enhancing the quality of human life, even at the expense of non-human life. The explicit recalling of the provisions of the Stockholm Declaration suggests that the ozone regime, too, takes a utilitarian approach to the environment.

Furthermore, while the ozone regime is concerned with phasing out substances that deplete the ozone layer, it is not concerned with limiting the activities that rely on these substances. Taken together with its recalling of the provisions of the Stockholm Declaration, the ozone regime arguably supports ‘sustainable’ development, which has been described as an ‘epistemology of mastery’ (Adelman Reference Adelman, Grear and Kotzé2015: 22) and as ‘so conveniently malleable that it enables its proponents to mask the negative socio-ecological impacts of relentless growth-driven development promoted by states and corporations’ (Kotzé & Adelman Reference Kotzé and Adelman2023: 3). Problematically, sustainable development is central to environmental law and governance (Kotzé & Adelman Reference Kotzé and Adelman2023; Schmidt Reference Schmidt2022).

As the world warms, demand for air conditioning and refrigeration (the primary applications of HFCs) will increase and coolants will become increasingly important to health, well-being, and life itself, particularly in developing countries. However, coolants such as HFCs contribute to global warming which will, in turn, further increase the demand for coolants (the ‘cooling paradox’ (IISD 2021)). Such uses should be contrasted against the use of refrigeration for the transport of food to wealthy countries and the use of air conditioning in private motor vehicles. Recent research shows that almost 20 per cent of greenhouse gas emissions from the food sector are generated by the transport of food across and between countries, with wealthy countries making a disproportionately large contribution to the problem (Li et al. Reference Li, Jia and Lenzen2022). In addition, temperature-controlled transport is required for vegetables and fruit which further increases their food miles emissions. Low-income countries were responsible for generating just 20 per cent of food transport emissions (Malik & Li Reference Malik and Li2022). Such ‘luxury’ uses are not questioned by the ozone regime.

To the extent that the ozone regime implicitly supports continued ‘sustainable’ development (and the continued use of substances that are potentially harmful to earth system components), socio-ecological harms and injustices will likely continue. Adelman points to the challenges of reconciling the welfare of humans and the planet under mainstream forms of development (Adelman Reference Adelman, French and Kotzé2021: 68); and others argue that achieving equity (between humans) within planetary boundaries will require reduced consumption in the North (Steffen & Stafford Smith Reference Steffen and Stafford Smith2013; Hickel Reference Hickel2019). It is thus increasingly recognized that alternatives to mainstream forms of development (such as sustainable development), which are centred around growth, are required (see, e.g., Hickel et al. Reference Hickel, Kallis and Jackson2022; Kotzé & Adelman Reference Adelman, French and Kotzé2021).

A further concern is that the development of newer technologies and the tightening of standards in developed countries have resulted in inefficient equipment, containing ODSs due to be phased down or phased out, being offloaded in developing countries, which will bear the associated environmental, economic, and social costs. Developing countries have accordingly called for policies and measures to prevent such dumping (Agyarko et al. Reference Agyarko, Andersen and Ferris2021; UNEP 2022).

Furthermore, the ozone regime is grounded in science, and the Montreal Protocol has been referred to as an example of ‘the power of Earth systems science in facilitating international environmental lawmaking’ (Boyd Reference Boyd2017: 486). The ozone regime provides that measures to protect the ozone layer should be based on scientific knowledge, and there are references throughout the Vienna Convention and Montreal Protocol to scientific and technical information. Interestingly, around the time that the Vienna Convention and Montreal Protocol were concluded, economic growth came to be linked to scientific and technological progress; and Allan argues that the ‘tight link between growth and scientific and technological progress continues to be reproduced in the present international order’ (Allan Reference Allan2018: 261). In practice, knowledge is developed by several scientific and technical assessment panels, which are largely dominated by men from northern countries (see, e.g., UNEP n.d.).

Although the problem of stratospheric ozone depletion was caused by human-created substances, ozone depletion and other problems arising due to the implementation of the ozone regime have implications for all life on earth. The absence of references in the ozone regime to natural ecosystems (apart from references to ‘human health and the environment’) and non-state actors – in contrast to other IEL agreements – is striking.

The following section begins to explore how some of these concerns might be addressed.

3.4 The Evolution of Values under the Ozone Regime

While some of the aforementioned concerns might be addressed through the tightening of definitions and narrowing of exclusions (see Du Toit Reference Du Toit, Kulovesi, Yamineva and Recio2023), the focus here is on deeper shifts that might be required. At a broader level, there have been calls for the transformation of ‘modern society’s anthropocentric and colonial worldview through which nature exists to serve humankind’ (Piccolo et al. Reference Piccolo, Taylor and Washington2022: 1). In the context of international law, it has been argued that reforms of international laws and institutions are required in order to ‘make them less anthropocentric and more responsive to the imperatives of the global ecological crisis’ (Lawrence Reference Lawrence2022: 577). However, there is no consensus on how this could be achieved.

A growing trend, prominent at the national level, is the granting of rights to nature generally or to specific natural entities, such as rivers (see, amongst others, Boyd Reference Boyd2017; Kotzé & Villavicencio Calzadilla Reference Kotzé and Villavicencio Calzadilla2017; Villavicencio Calzadilla & Kotzé Reference Villavicencio Calzadilla and Kotzé2018; Tănăsescu Reference Tănăsescu2020). While the recognition of rights for nature might present a response to concerns around anthropocentrism in environmental law, several problems have been highlighted. For example, granting rights to nature may further entrench divisions between human and non-human earth system components (Biber Reference Biber2022; O’Donnell Reference O’Donnell2022). Furthermore, Tănăsescu challenges the assumption that rights of nature are ecocentric or of Indigenous origin and argues that extending personhood to natural entities ‘reproduces the centrality of the human’ (Tănăsescu Reference Tănăsescu2020: 448), which clearly does not address concerns regarding the anthropocentrism of IEL. Spitz and Penalver (Reference Spitz and Penalver2021: 81) also question whether granting personhood to natural entities actually makes a difference in terms of legal outcomes; and Kurki (Reference Kurki2022) goes further, arguing that granting personhood to natural entities is simply a legal fiction (even though it may have symbolic value). While not possible to explore fully here, the value of granting procedural rights to natural entities has also been highlighted (Schapper et al. Reference Schapper, Hoffmann and Lee2022; see also Tănăsescu Reference Tănăsescu2020; Winter Reference Winter2021).

It has also been proposed that ecological integrity or ‘the integrity of Earth’s life-support systems’ should be established as a grundnorm of international law, ‘similar to the grundnorm character that human rights or the rule of law have in domestic and international law’ (Kim & Bosselmann Reference Kim and Bosselmann2015: 194). Adelman argues further that ‘ecological integrity should be both a precondition and the ultimate objective of [international environmental law] in order to stay within the safe operating space of the planetary boundaries’ (Adelman Reference Adelman, French and Kotzé2021: 77). Some IEL agreements have recently started to recognize the importance of ecological integrity. For example, the Paris Agreement (UNFCCC 2015: Preamble) emphasizes ‘the importance of ensuring the integrity of all ecosystems, including oceans, and the protection of biodiversity, recognized by some cultures as Mother Earth’. The Glasgow Climate Pact contains similar language, and it notes ‘the importance of ensuring the integrity of all ecosystems, including in forests, the ocean and the cryosphere, and the protection of biodiversity, recognized by some cultures as Mother Earth’. While not binding, the 1982 World Charter for Nature (UNGA 1982) arguably goes even further through its acknowledgement of the intrinsic value of nature in the following terms: ‘[hu]mankind is a part of nature and life depends on the uninterrupted functioning of natural systems’, and ‘[e]very form of life is unique, warranting respect regardless of its worth to [humans]’. Attention could be paid to including similar language within the preambular text of the ozone regime.

In regard to concerns around the predominant reliance on (Western) scientific knowledge, Garver (Reference Garver2019: 167) argues that achieving a ‘mutually enhancing human-Earth relationship’ requires that human choices are informed by contemporary science as well as ‘traditional ecological knowledge of people with long-standing connections to place, including an understanding of the behavior of complex adaptive systems’. More recently, some IEL treaties have started to refer to non-Western knowledge. For example, under the climate change regime, the Paris Agreement (UNFCCC 2015: article 7(5)) acknowledges that ‘adaptation action should follow a country-driven, gender-responsive, participatory and fully transparent approach, taking into consideration vulnerable groups, communities and ecosystems, and should be based on and guided by the best available science and, as appropriate, traditional knowledge, knowledge of indigenous peoples and local knowledge systems’. Similarly, the Glasgow Climate Pact (UNFCCC 2021: article 93) emphasizes ‘the important role of indigenous peoples’ and local communities’ culture and knowledge in effective action on climate change and urges Parties to actively involve indigenous peoples and local communities in designing and implementing climate action’. It would also be possible to include this type of language within the preambular provisions of the ozone agreements.

More broadly, it will be necessary to move beyond ‘mainstream forms of development’ (Adelman Reference Adelman, French and Kotzé2021: 68) and the current ‘growth-insistent paradigm’ (Garver Reference Garver2019). Proposals include embracing non-Western perspectives such as sumac kawsay or buen vivir (Acosta Reference Acosta2017) and implementing degrowth strategies (Hickel et al. Reference Hickel, Kallis and Jackson2022). Buen vivir translates directly as ‘living well’; although it is said to translate more accurately as ‘harmonious coexistence’ (Calisto Friant & Langmore Reference Calisto Friant and Langmore2015: 1). For its part, the degrowth concept originated in ecological economics, and it is described as ‘a planned reduction of energy and resource use designed to bring the economy back into balance with the living world in a way that reduces inequality and improves human well-being’ (Hickel Reference Hickel2021: 1105). Embracing such perspectives is viewed as important to efforts to shift away from the anthropocentric basis of law and governance and to tackle the socio-ecological challenges of the Anthropocene (see, e.g., Calisto Friant and Langmore Reference Calisto Friant and Langmore2015; Kotzé & Adelman Reference Kotzé and Adelman2023). However, their realization would go beyond the scope of the ozone regime, and indeed IEL, and would require wide-ranging societal and political transformations.

In the interim, measures like those described earlier, such as the recognition of ecological integrity and non-Western perspectives within the ozone regime, could represent starting steps in shifting away from anthropocentric and utilitarian values, and they could also bring the ozone regime in line with more recently concluded IEL agreements.

3.5 Concluding Remarks

The ozone regime is widely considered to be one of the most effective international law regimes to date. While it has been very successful in regard to phasing out the substances under its control and in ensuring that we remain within the planetary boundary on stratospheric ozone depletion, the earlier discussion has highlighted several concerns. Apart from several technical gaps, it has been argued that the ozone regime (similarly to IEL in general) is based on a utilitarian and human-centred approach and implicitly supports ongoing ‘sustainable’ development, which has given rise to various socio-ecological harms. Furthermore, although it has been argued that the ozone regime gives effect to the principle of common but differentiated responsibilities, as discussed earlier, power imbalances between developed and developing countries remain, which enable the exacerbation of injustices. While not presenting definitive answers, this chapter has attempted to explore the evolution of values underlying the ozone regime so that it may continue to effectively protect stratospheric ozone, while also contributing to efforts to equitably protect all earth system components.