The Climate Regime and Other Areas of Law

In: Climate Law
Margaret A. Young Melbourne Law School, University of Melbourne, Melbourne, Vic, Australia

Search for other papers by Margaret A. Young in
Current site
Google Scholar
Markus W. Gehring Faculty of Law, University of Cambridge, Cambridge, United Kingdom

Search for other papers by Markus W. Gehring in
Current site
Google Scholar
Open Access

This article is an introduction to a special issue of Climate Law that examines climate change law in the context of other areas of law. The special issue collects selected papers from a workshop entitled ‘The Climate Change Regime and Public International Law’ organized by the authors and held on 12–13 December 2022 at the Lauterpacht Centre for International Law, University of Cambridge. It was supported by a research partnership between Melbourne Law School and Cambridge University’s Faculty of Law. The workshop was aimed at scholars in the early part of their careers (PhD candidates and early-career researchers), with senior scholars as commentators. Five of the papers from the workshop were selected as research articles or shorter commentaries for this special issue.

The workshop theme comes from the recognition that while the unfccc and the Paris Agreement elaborate rights and duties of states relating to climate change mitigation and adaptation, they do not operate in isolation. The climate treaties and their supporting institutions, which make up the international legal regime addressing climate change,1 exist alongside custom, other treaties, and general principles of law that are relevant to the climate crisis. So much is obvious from the question currently posed to the International Court of Justice (icj) in the General Assembly’s request for an advisory opinion on climate obligations.2 In addition, the climate regime operates alongside and influences domestic legislation and case law, private directives, local council activities, and other norms. The implementation of international climate law is facilitated or constrained at the domestic level by those other areas of law.3 In conditions of pluralism, different legal orders operate alongside one another: domestic, international, transnational, subnational, and often indigenous. Rather than seek to offer a comprehensive account of regime interaction or of the ‘regime complex’4 for climate change, the special issue focuses on specific examples that include human rights, investment agreements, water law, coal regulation, and planning law.

The questions canvassed in this special issue arise at a time of multiple requests for advisory opinions which address systemic issues traversing international regimes.5 The request for an advisory opinion at the icj was adopted by consensus at the General Assembly and has particular relevance. The way in which the Court has been asked to advise on obligations under the climate regime and other areas of international law prompts reflection on the special issue’s themes. Although the icj has general jurisdiction to apply all areas of law it deems relevant to climate obligations, the legal question posed to the Court draws the Court’s attention, in its introductory paragraph, to the UN Charter, human rights treaties, the law of the sea, the duty of due diligence, and customary norms that have evolved from the duty to prevent transboundary harm.6 The Court is asked to have ‘particular regard’ to these areas of law in establishing the obligations of states under international law in respect of climate change.

Should it issue an advisory opinion, the Court may provide legal advice about obligations of states that have expanded and fragmented in areas of professional specialization and functions.7 Integrating the relevant duties will be possible and desirable in some but not all cases. For example, states may be complying with their commitments under the climate regime but be violating their obligations under other areas of law, such as the duty to prevent significant harm to the climate system. In addition, the ambition for ‘common but differentiated responsibilities’ in the Paris Agreement operates differently in the context of the law of the sea, which though addressing issues of equity does not differentiate obligations.8 As the literature on fragmentation makes clear, regime collisions are sometimes unavoidable.9 Even if a single set of obligations to protect the atmosphere is articulated, the International Law Commission urges that ‘special consideration should be given to persons and groups particularly vulnerable to atmospheric pollution and atmospheric degradation’.10 This may provide guidance for the icj as it seeks to preserve unity amongst the ‘widening and thickening of the context of international law’.11

The icj’s consideration of the Universal Declaration of Human Rights, the iccpr, and the icescr can be expected to be an important aspect of any advisory opinion issued.12 Framing climate obligations in terms of the duties of states to protect human rights extends the understanding of their duties to mitigate and adapt, but also helps address seemingly intractable matters such as ‘loss and damage’.13 Human rights law also helps support the appropriate implementation of states’ climate responses, including when policy measures impact indigenous communities and other marginalized groups.14

Human rights law is augmented through commentaries and decisions of the relevant treaty bodies, which are themselves no strangers to different areas of law. For example, when the Human Rights Committee answered a complaint about alleged iccpr violations due to failures to respond to climate change, it ruled against the respondent state’s challenge to admissibility based on that state’s claim that the climate regime was not relevant to the iccpr.15 The converse situation, including whether and how human rights jurisprudence can be taken into account in the icj’s reasoning, is addressed by Rebecca McMenamin in this special issue. In ‘Advisory Opinion on Obligations of States in Respect of Climate Change: Potential Contribution of Human Rights Bodies’, McMenamin reviews the icj’s sources of law and interpretative tools to show that the icj can indeed draw upon the views of the UN treaty bodies, including from complaints like the one brought against Australia. She also shows how the human rights jurisprudence is relevant in substance to any ultimate advice, arguing that the Court should give weight to the treaty bodies’ findings on the rights to life, home life, and culture, and the treaties’ extraterritorial reach.

The duty of due diligence is also referred to in the icj request. The due diligence required of a state in its territory is linked to the principle of prevention, now a customary rule, according to which states must ensure activities within their jurisdiction and control do not cause significant harm to the environment.16 The duty provides an important standard of conduct for the icj when it seeks to understand obligations to prevent harm to the climate system.17 Such standard-setting operates in private law too, and is addressed to private actors. Here too is an example of cross-cutting norms: the concept of due diligence by business enterprises is at the heart of the UN Guiding Principles on Business and Human Rights.18 An entire part of the UN Guiding Principles is dedicated to human rights due diligence, highlighting the duty of companies to be informed about, prevent, and address human rights impacts.19 In his research article in this Special Issue, ‘Human Rights Due Diligence and the Climate Change Dimension: Implications for Investor Responsibility in International Investment Law’, Sek Lun Cheong argues for the human rights due diligence familiar from the business and human rights framework to be applied to climate change and contrasts this development with the international investment regime. He highlights the increasing convergence and integration between the UN General Principles’ framework of human rights due diligence and climate change. While in international investment law this aspect is much less developed, he shows that increasing recognition of human rights responsibilities of foreign investors could serve as a pathway to increased investor responsibility for climate-related harm as well.

Seeking to understand the position of the climate regime vis-à-vis other areas of law is in no way intended to undermine its centrality in attempts to strengthen the global response to the threat of climate change. The target of keeping the rise in global average temperature to 1.5°C or 2°C above pre-industrial levels provides a focus for states and private actors.20 Making finance flows consistent with low greenhouse gas emission pathways is an ongoing quest, with its own expectations about domestic law.21 The Nationally Determined Contributions, which all parties must prepare, communicate, and maintain, are an important tool for states to implement their commitments and meet their collective obligations.22

The climate cops continue to operationalize the rights and duties within the climate regime. For example, the Glasgow Climate Pact23 includes as an objective the ‘phase-down’ of unabated coal power. In her commentary in this special issue, Ella Vines investigates the role of the Paris Agreement in domestic litigation challenging the approval of Australian coal projects. Australia has not participated in the climate regime’s ‘Powering Past Coal Alliance’, and the government’s executive branch continues, in 2023, to permit new coal mines. Yet the judiciary provides another source of state practice, and Vines’s commentary tracks the outcomes of Australian coal litigation. While climate change mitigation requires far more than phasing out coal, the Australian context is illustrative of how at least some domestic jurisdictions are locating authority from the climate regime to act on coal extraction.

Domestic developments in the United Kingdom are the focus of Alistair Mills’ research article, ‘Meeting Lofty Aspirations? English National Planning Policy, International Law, and Climate Change’. He highlights the importance of the national framework of the UK planning system for the transition to a more sustainable future, including seeking to reduce or avoid greenhouse gas emissions. In its reference to sustainable development and intergenerational equity, both equally important in international law,24 Mills analyses recent case law and demonstrates how intergenerational equity has not been used in practice. His article suggests potential changes to policy so as to provide greater support for mitigation of emissions. It develops the idea of taking the international obligations of a country under the Paris Agreement seriously and using them to influence the content of policy.

Water law is an area of increasing relevance to the climate regime, giving rise to questions about the relationship between various laws and concepts. In Roanna McClelland’s commentary on ‘Rights of Rivers in a Changing Climate’, developments surrounding legal personhood (such as the recognition of the Whanganui River of New Zealand in 2017 as a legal person)25 are addressed. McClelland investigates the potential consequences of ‘rights of rivers’ in the ongoing endeavour to integrate climate and water policy. The Sharm el-Sheikh Implementation Plan26 recognizes the need for ‘protecting, conserving and restoring’ water systems. River rights can advance the goals of adaptation foundational to the climate regime, but they are not without difficulties, due to their locally specific implementation. Multiple questions arise for climate lawyers: for example, if rivers hold rights, do they also hold duties, including responsibility for harm from flooding and other extreme weather events caused by climate change? Amongst these and other legal uncertainties, McClelland documents the influence of indigenous voices – and indigenous law – in the expression of riverine rights, which may bring important perspectives about nature and ‘Mother Earth’ in climate change mitigation and adaptation.27 Mills, Vines, and McClelland’s analyses of relevant advocacy in domestic litigation around the world is an essential contribution to studies of climate-litigation strategies at the domestic level,28 and to the workshop’s aim of examining climate law in the context of other areas of law.

This special issue is of course not comprehensive in its account of the areas of law to which current requests for advisory opinions before the icj and other tribunals refer. One question that is raised in both the icj and itlos requests is the content of states’ duties to protect and preserve the marine environment in the context of climate change.29 The itlos advisory request centres on the United Nations Convention on the Law of the Sea (unclos), and poses questions about the obligations of parties to ‘prevent, reduce and control pollution of the marine environment’30 in the context of ocean warming, sea-level rise, and ocean acidification. These physical developments caused by greenhouse gas emissions were not anticipated in unclos; however, the Convention’s definition of ‘pollution’ is expansive,31 as are the duties of states to ‘protect and preserve the marine environment’.32 While some states submit that the operationalization of these duties is encompassed by ndcs under the Paris Agreement,33 itlos may find it necessary to tailor its findings more closely to the marine context, particularly given the specificities of the duty of due diligence in the law of the sea.34

Unlike the law of the sea, the biodiversity regime is not expressly addressed in the General Assembly’s request to the icj. This is not to say that obligations of states with respect to biodiversity protection are irrelevant to the request. The aspiration of the Kunming-Montreal Global Biodiversity Framework35 is to galvanize urgent and transformative action to halt and reverse biodiversity loss, while supporting action of states that is consistent with other treaties.36 As states and other actors seek to implement those goals and targets, they do so with the knowledge that climate change is the third biggest direct driver of change in nature.37 Such drivers need to be reduced or reversed ‘to allow for the recovery of all ecosystems and to achieve the Convention’s vision of living in harmony with nature by 2050’.38 The General Assembly’s request does not ask the Court to opine on obligations toward nonhuman species,39 which would have formed a more direct link to biodiversity protection. But the joining of the climate regime’s language of ‘nature-based solutions’ with the ‘eco-system-based approaches’ of the biodiversity regime40 is one of many important links.

A set of laws that is increasingly set against the climate regime comes from trading relationships.41 On the one hand, trade liberalization in environmental goods and services makes states’ clean-energy transition cheaper and more efficient. On the other, the norm of non-discrimination may not be the best domestic motivator for the local acceptance of climate policies.42 Preferential trade agreements increasingly seek to harmonize net-zero goals,43 while the use of trade-related climate measures such as border carbon-adjustment measures dominate climate policy.44 There are varying views about the application of the principle of common but differentiated responsibilities.45 Trade law’s close relative, investment law, raises similar questions, especially in the context of a compulsory dispute settlement system which is likely to engage arbitrators whose professional work is normally outside of the domain of greenhouse gas emissions.

With these and other examples contained in the special issue, strengthening the global response to climate change is at once about the climate regime and about other areas of law which may constrain or facilitate climate ambition. It is fitting that the workshop met at the Lauterpacht Centre, where in 2009 one of the present authors convened a conference that became the book Regime Interaction in International Law. The contributors to that book showed the importance of addressing the interaction between international regimes at all stages of international law-making, implementation, and dispute settlement. Climate cops confirm the insight that ‘operational interactions can generate impressive substantive initiatives and outcomes in ways that international litigation cannot’.46 In addition, the exploration of judicial deference, mutual respect, and comity between international tribunals is instructive, as the advisory opinions on climate obligations run in parallel.47

The articles and commentaries in this special issue are offered as scholarship, but also as a human response to the urgency and immediacy of the climate crisis. For the workshop attendees this was more than an abstraction: many experienced floods in New South Wales and Victoria (Australia) and heatwaves in the United Kingdom during the seasons preceding our meeting,48 while also recognizing that these events occurred in industrialized countries with historically high emissions and a comparatively high capacity to adapt.49 There was high motivation for face-to-face engagement between early career scholars, many of whom had conducted their research mostly in pandemic-induced lockdowns. The opportunity for traditional academic exchange has been diminished over the past few years; despite the good reasons to counter its full revival,50 meeting together was much appreciated.

In conclusion, this special issue demonstrates the diversity of legal responses and contexts to climate change, as they operate internationally, transnationally, domestically, and locally. It does so with consciousness about the need to strengthen the climate regime, and also supportive of other efforts to guide mitigation and adaptation. Even if each country’s ndc under the Paris Agreement is fully complied with, the world is on track for 2.8°C of warming.51 Recognizing that many actors, at many levels, in all areas of economic and social relations, have a role to play in addressing climate change is a key contribution of this special issue. Conversely, recognizing how rights and duties under many areas of the law might constrain the transformative economic and social changes that are required to limit warming to 1.5°C or 2°C above preindustrial levels is essential.52 Although international law is a system, the different areas of law are not always mutually supportive. How to give priority to the law that helps combat climate change depends on complex matters of substance and process.


The authors acknowledge the support of Melbourne Law School and Cambridge University’s Faculty of Law for the workshop, which brought together early-career researchers and PhD students from developed and developing countries who are based at the Universities of Melbourne, Cambridge, Oxford, King’s College London, University College London, Vienna, Aix-Marseille, Zurich, and Georg-August-Universität Göttingen. We note our special thanks to Marie-Claire Cordonier Segger, Joana Depledge, Campbell McLachlan, Sundhya Pahuja, Jacqueline Peel, and Christina Voigt, who acted as commentators. We also thank the Editor and peer reviewers who supported the resulting research articles and commentaries.


Regimes here are ‘sets of norms, decision-making procedures and organisations coalescing around functional issue-areas and dominated by particular modes of behaviour, assumptions and biases’: Margaret A. Young, ‘Introduction: The Productive Friction between Regimes’, in Regime Interaction in International Law: Facing Fragmentation, edited by Margaret A. Young (Cambridge: Cambridge University Press, 2012), 1–19, at 11.


Request for an Advisory Opinion of the International Court of Justice on the Obligations of States in Respect of Climate Change, UN General Assembly, UN Doc. a/res/77/276 (2023) (hereinafter icj Advisory Opinion Request); see also Obligations of States in Respect of Climate Change (Request for an Advisory Opinion), icj Order, General List No. 187, 20 April 2023.


See further Margaret A. Young, ‘Climate Change and Law: A Global Challenge for Legal Education’, 40(3) University of Queensland Law Journal 351 (2021), 358–62.


When first defined, this concept included the UN legal regimes of the unfccc and Kyoto Protocol: Robert O. Keohane and David G. Victor, ‘The Regime Complex for Climate Change’, 9 Perspectives on Politics 7 (2011); see also Margaret A. Young, ‘Climate Change Law and Regime Interaction’, 2 Carbon and Climate Law Review 147 (2011).


icj Advisory Opinion Request, supra note 2; Request for an Advisory Opinion Submitted by the Commission of Small Island States on Climate Change and International Law (12 December 2022) (hereinafter itlos Advisory Opinion Request); see also Order 2023/4, List of Cases No. 31, 30 June 2023. Note also ‘Chile and Colombia agree to consult with the Inter-American Court on the impact of the environmental crisis on human rights’ (Cancilleria, 9 January 2023), <>.


icj Advisory Opinion Request, supra note 2.


ilc, Fragmentation ilc Study Group, Fragmentation of International Law: Difficulties arising from the Diversification and Expansion of International Law, Report of the Study Group of the International Law Commission, finalized by Martti Koskenneimi (a/cn.4/l.682 and Corr.1) (13 April 2006).


Ellen Hey, ‘Regime Interaction and Common Interests in Regulating Human Activities in Areas Beyond National Jurisdiction’, in Regime Interaction in Ocean Governance: Problems, Theories and Methods, edited by Seline Trevisanut, Nikolaos Giannopoulos, and Rozemarijn Roland Holst (Leiden; Boston: Brill Nijhoff, 2020), 85, at 94–7. See also Responsibilities and Obligations of States Sponsoring Persons and Entities with Respect to Activities in the Area (International Tribunal for the Law of the Sea, Advisory Opinion of 1 February 2011), para. 149.


Young, supra note 1, 7–8.


ilc, Draft Guidelines on the Protection of the Atmosphere, With Commentaries, 2021, A/76/10, Guideline 9.


See Rosalyn Higgins, ‘A Babel of Judicial Voices? Ruminations from the Bench’, 55 International and Comparative Law Quarterly 791 (2006), 792.


Other human rights treaties are also relevant, even though they are not specified in the General Assembly’s request, supra note 2. See e.g. on the Convention on the Rights of the Child: General Comment No. 26 (2023) on Children’s Rights and the Environment with a Special Focus on Climate Change (22 August 2023) (crc/c/gc/26).


See further Annalisa Savaresi and Joanne Scott, ‘Implementing the Paris Agreement: Lessons from the Global Human Rights Regime’, 9 Climate Law 159–64 (2019).


Maureen Tehan, et al., The Impact of Climate Change Mitigation on Indigenous and Forest Communities (Cambridge: Cambridge University Press, 2017), esp. 87–129.


Billy v. Australia, UN Doc. ccpr/c/135/d/3624/2019 (2022); see paras 4.1 and 7.5.


Case concerning Pulp Mills on the River Uruguay (Argentina v. Uruguay), 2010 icj Reports 14, 55–6, para. 101; see also Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, icj Reports 1996 (I), 241–2, para. 29.


icj Advisory Opinion Request, supra note 2. See further, Sandrine Maljean-Dubois, ‘The No-Harm Principle as the Foundation of International Climate Law’, in Debating Climate Law, edited by Benoit Mayer and Alexander Zahar (Cambridge: Cambridge University Press, 2021), 15.


‘Guiding Principles on Business and Human Rights: Implementing the United Nations “Protect, Respect and Remedy”’, Annex to unhrc, Report of the Special Representative of the Secretary-General on the Issue of Human Rights and Transnational Corporations and Other Business Enterprises, John Ruggie (21 March 2011), UN Doc. a/hrc/17/31.


Ibid., Principles 15–24. See further Jonathan Bonnitcha and Robert McCorquodale, ‘The Concept of “Due Diligence” in the UN Guiding Principles on Business and Human Rights’, 28(3) European Journal of International Law 899 (2017).


Paris Agreement, Article 2(1).


Ibid., Article 2(1)(c). Such expectations are not without problems; see further Megan Bowman, ‘Turning Promises into Action: “Legal Readiness for Climate Finance” and Implementing the Paris Agreement’, 1 Carbon and Climate Law Review 41 (2022).


Paris Agreement, Articles 3 and 4.


unfccc, Decision 1/cp.26, Glasgow Climate Pact, fccc/cp/2021/12/Add.1 (2021).


See Marie-Claire Cordonier Segger, Marcel Szabó, and Alexandra R. Harrington (eds), Intergenerational Justice in Sustainable Development Treaty Implementation: Advancing Future Generations Rights through National Institutions (Cambridge University Press, 2021).


Te Awa Tupua (Whanganui River Claims Settlement) Act 2017 (NZ).


unfccc, Decision 1/cp.27, Sharm el-Sheikh Implementation Plan, fccc/cp/2022/l.19 (2022).


Paris Agreement, Preamble (‘Noting the importance of ensuring the integrity of all ecosystems, including oceans, and the protection of biodiversity, recognized by some cultures as Mother Earth’); see also Decision 15/4, UN Doc. cbd/cop/dec/15/4 (2022) (hereinafter Kunming-Montreal Declaration), para. 7(b).


See Christina Voigt, ‘The Power of the Paris Agreement in International Climate Litigation’, 32(2) reciel 237–49 (2023); see also Ivano Alogna, Christine Bakker, and Jean-Pierre Gauci (eds), Climate Change Litigation: Global Perspectives (Leiden: Brill Nijhoff, 2021).


icj Advisory Opinion Request, supra note 2; itlos Advisory Opinion Request, supra note 5.


unclos, Article 194.


Ibid., Article 1.


Ibid., Article 192 and Part xii in general.


See, e.g., Request for an Advisory Opinion Submitted by the Commission of Small Island States on Climate Change and International Law: Written Statement of Australia (16 June 2023), paras 39–41; 61.


Responsibilities and Obligations of States with Respect to Activities in the Area, supra note 5; see also Request for an Advisory Opinion submitted by the Sub-Regional Fisheries Commission (srfc) (International Tribunal for the Law of the Sea, Advisory Opinion of 2 April 2015), paras 131–50.


Kunming-Montreal Global Biodiversity Framework, supra note 27.


Ibid, para 7(j) (‘The Framework needs to be implemented in accordance with relevant international obligations. Nothing in this Framework should be interpreted as agreement to modify the rights and obligations of a Party under the Convention or any other international agreement’).


Ibid., para. 2.


Ibid., para. 9.


See, e.g., efforts to provide rights ‘to a secure, healthy and ecologically sound Earth system’ for all ‘human beings, animals and living systems’ in the civil-society-led declaration: Kirsten Davies, et al., ‘The Declaration on Human Rights and Climate Change: A New Legal Tool for Global Policy Change’, 8(2) Journal of Human Rights and the Environment 217–53 (2017).


Kunming-Montreal Global Biodiversity Framework, supra note 27, para. 7(m).


See International Legal Expert Group on Trade-Related Climate Measures and Policies, Principles of International Law Relevant for Consideration in the Design and Implementation of Trade-Related Climate Measures and Policies, Forum on Trade, Environment, and the sdgs (tess) (2023).


Timothy Meyer, ‘Taxing, Regulating, and Trading Carbon: An Introduction to the Symposium’, 116 ajil Unbound 191 (2022).


See e.g. Margaret A. Young and Georgina Clough, ‘Net Zero Emissions and Free Trade Agreements: Efforts and Integrating Climate Goals by the United Kingdom and Australia’, 72(2) International and Comparative Law Quarterly 393–436 (2023).


See Markus W. Gehring, ‘European Union Trade Measures and Highest Priority Challenge Related to Climate Change in EU-Americas Relations’, 50(3) Legal Issues of Economic Integration 1–24 (2023).


International Legal Expert Group, supra note 41.


Jeffrey Dunoff, ‘A New Approach to Regime Interaction’, in Young (ed.), supra note 1, 136, 166.


James Crawford and Penelope Nevill, ‘Relations between International Courts and Tribunals: The “Regime Problem”’, in Young (ed.), supra note 1, 235, 242–3.


See further Environment Agency, State of the Environment: Health, People and the Environment (updated 26 January 2023), <>; see also Commonwealth of Australia, State of the Climate (2022), <>.


ipcc, ‘Summary for Policy Makers’, in Synthesis Report (6th Assessment, 2023), para. A.2.


See, e.g., current internal Polis survey within the University of Melbourne about staff air-travel emissions (2023, pending publication of findings).


unep, Emissions Gap Report 2022: The Closing Window (2022).


See further Young, supra note 3, 366–8.

Content Metrics

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 489 490 173
PDF Views & Downloads 642 642 92