Informal institutions in global governance are generally expected to favor powerful states. According to conventional arguments, procedural justice is best secured through formal institutional rules that constrain power, while informal institutions reinforce power asymmetries. This chapter revisits this position and asks, how and under what conditions can informal institutions enhance the voice and influence of less powerful or marginalized actors in global governance? The chapter argues that while informal institutions are useful to powerful states because they remove constraints to individual action, they can also be useful to less powerful states to the extent that they positively support action through social-integrative effects. Specifically, interactions within informal groups generate two types of social effects – capacity-building and coalition-building – that can enhance the voice of developing countries and increase their control over collective decisions. The chapter illustrates the arguments by profiling informal groups in the global governance of trade and finance.

We assess the development of informality in international climate policy on two levels: Whether informal organizations meaningfully contribute to climate change mitigation, and what role informality plays under the UN Framework Convention on Climate Change (UNFCCC). Proliferation of informal intergovernmental organizations (IIGOs) has enabled the move from a rigid list of countries with and without commitments, to the Paris Agreement, under which each country contributes to mitigation. Within the UNFCCC process, we find a “formality-informality cycle,” in which actors sometimes render rules and procedures more flexible and hence more efficient, only to suddenly reverse this trend at other times. Such a high-profile reversal occurred in Copenhagen in 2009. Subsequently, through the use of highly transparent negotiation procedures, trust in informality increased again, allowing negotiators to successfully override Nicaragua’s opposition in Paris in 2015. Similar formality-informality cycles can be observed on specific topics within the UNFCCC negotiations, such as international market mechanisms.

Chapter 4 analyses the three selected challenges facing international tribunals – managing change, reviewing State conduct for compliance with international law, and dispute resolution – in the International Court of Justice (ICJ)’s environmental case law. The ICJ has repeatedly adapted aging treaty frameworks given relevant developments in international law and has also faced the problem of change in relevant facts. While the terminology of a standard of review is not firmly established in the ICJ’s case law, the underlying functional problem – concerning the intensity of an international tribunal’s scrutiny of determinations made by domestic authorities – is clearly present. Although three-step proportionality analysis is not entrenched in the ICJ’s case law, the Court has repeatedly used a reasonableness-based test that operates similarly to least restrictive means testing. Finally, the ICJ often adjudicates in a forward-looking, facilitative manner, seeking to assist the parties to manage their relationship after adjudication. Throughout, the chapter reflects on how the ICJ’s practices are shaped by its institutional features, such as its lack of any compulsory jurisdiction.

Chapter 1 introduces the questions the book focuses on and explains its key contributions to literature on international adjudication. It introduces the three challenges facing international tribunals analysed throughout the book: managing change in applicable law or relevant facts, determining the appropriate standard and method of review when scrutinising State conduct for compliance with international law, and contributing to broader processes of dispute resolution. The chapter explains why the book focuses on environmental disputes, as such disputes lack a dedicated tribunal and are litigated across various regimes, and how it defines such disputes. It also justifies the choice of the four adjudication contexts focused upon (adjudication in the World Trade Organization, the UN Convention on the Law of the Sea, the International Court of Justice, and under investment treaties). The chapter also notes certain insights the book incorporates from methodological debates in comparative law, given its focus on identifying and explaining similarities and differences in how the three selected challenges are managed across the four adjudication contexts studied.

Chapter 3 analyses the three selected challenges facing international tribunals – managing change, reviewing State conduct for compliance with international law, and dispute resolution – in the environmental case law of the International Tribunal for the Law of the Sea (ITLOS) and arbitral tribunals constituted under the UN Convention on the Law of the Sea (UNCLOS). UNCLOS tribunals have often interpreted the Convention in a manner that takes account of relevant developments in international law. This is partly due to features of UNCLOS itself, including that it contains many generic or open-ended terms. The chapter demonstrates that the standard and method of review are significant issues in the environmental case law of UNCLOS tribunals, in the context of the Convention conferring on coastal States discretionary powers. These issues raise similar functional questions to those seen in the other adjudication contexts studied, for example regarding the rationales for some deference to domestic authorities. Finally, the chapter demonstrates that UNCLOS tribunals often adjudicate in a facilitative, forward-looking manner, aiming to assist the parties to rebuild their relationship.

Chapter 6 draws together and extends the comparative analysis that has unfolded across the prior chapters. It explains why tribunals’ practices differ across the regimes studied, focusing on contextual differences between the selected tribunals. It also assesses to what extent the practices of the selected tribunals provide insights into wider problems facing international adjudication and legal techniques that are potentially transferable across contexts. Structurally, the chapter discusses consecutively my findings in relation to the three challenges confronting international tribunals analysed throughout the book: managing changes in international law or relevant facts, calibrating the appropriate standard and method of review when scrutinising State conduct for compliance with international law, and contributing to broader processes of dispute resolution. The chapter finishes with some final remarks that close the book, concerning its contribution to our understanding of the role of international adjudication in contemporary international law and its implications for future studies in this field.

The aim of this volume is not to provide or test a single theory of informal global governance but rather to provide a set of analyses that speak to a common set of theoretical, empirical, and methodological questions. More broadly, the aim is to advance the emerging research agenda on informality in world politics. We conclude the volume by highlighting four productive avenues for future research on informality, based on the insights of the empirical chapters.

Understanding contemporary global governance requires a focus on informality. States increasingly govern through informal intergovernmental organizations, transnational public–private governance initiatives, and other informal institutions. Even within formal institutions, informal practices complement or override formal rules. And diverse informal groupings operate in the orbit of governance institutions, framing novel issues and placing them on policy agendas. We address these three aspects of informality – of, inside, and around global governance institutions. We first trace the nature and extent of the shift toward informal governance. We then consider a range of factors that may be driving the shift, drawing on major streams of International Relations (IR) theory; we treat these as candidate explanatory variables. Finally, we summarize the findings on those variables, and other theoretical insights, from the empirical chapters of this volume.