What have scholars learned over the past decade about the forces that shape the creation, design, and adaptation of intergovernmental institutions in earth system governance and their influence on state behaviour? Context characteristics – shared, science-based knowledge; the behaviours involved; and the availability of alternative behaviours – can shape institutional creation, design and adaptation. The strategies states, existing institutions and non-state actors deploy, in turn, can promote institutional formation despite challenges or inhibit it despite propitious conditions. Context characteristics also can pose larger or smaller obstacles to institutional effectiveness. Institutions prove more effective when their designs reflect political, economic and social constraints as well as major actors’ power and incentives. They shape material, ideational and normative incentives and opportunities that channel states toward positive behaviours and away from negative ones. New research can build on recent findings by investigating complex interactions at and across the international, transnational, domestic and subnational levels of earth system governance.

There is a growing consensus in the literature that governance architectures matter. However, we lack sufficient knowledge about their emergence, dynamics and impacts. This concluding chapter summarizes all insights in the book Architectures of Earth System Governance, and emphasizes how this book has made a scientific contribution by enhancing conceptual clarity, synthesizing a decade of intense research, and charting directions for future research. The book has made at least one point clear: the ‘architecture lens’ offers a bird’s-eye view on the global governance landscape that is highly valuable in explaining outcomes of world politics. The architectures matter in how institutions interact with others, how institutions are entangled with others in larger regime complexes and how institutions are affected by broader architectures that are more or less fragmented or polycentric. In this concluding chapter, we also illustrate how such key insights gained could inform a set of transformative policy proposals regarding the architecture of earth system governance.

− Agency is one of five core analytical problems in the Earth System Governance (ESG) Project’s research framework, which offers a unique approach to the study of environmental governance. − Agency in Earth System Governance draws lessons from ESG–Agency research through a systematic review of 322 peer-reviewed journal articles published between 2008 and 2016 and contained in the ESG–Agency Harvesting Database.− ESG–Agency research draws on diverse disciplinary perspectives with distinct clusters of scholars rooted in the fields of global environmental politics, policy studies, and socio-ecological systems. − Collectively, the chapters in Agency in Earth System Governance provide an accessible synthesis of some of the field’s major questions and debates and a state-of-the-art understanding of how diverse actors engage with and exercise authority in environmental governance.

− ESG–Agency scholars have embraced the notion that agent influence is complex, contingent, and context dependent, with the success of environmental governance depending considerably on propitious environmental and social conditions. − Scholars have shifted from an earlier focus on how agents influence behaviours and environmental quality in earth system governance to how they influence governance processes, with increasing focus on democracy, participation, legitimacy, transparency, and accountability. − ESG–Agency scholars employ increasingly diverse methods to integrate insights from case studies, interviews, surveys, statistical analyses, and other approaches leading to deeper and more nuanced understanding of agency in earth system governance. − Adopting more interdisciplinary, multidisciplinary, and transdisciplinary approaches to evaluating agency can foster future understandings of and contributions to earth system governance.

Regime design matters. International treaties and regimes have value if and only if they cause people to do things they would not otherwise do. [Whether] a treaty elicits compliance or other desired behavioral changes depends upon identifiable characteristics of the regime's compliance systems. As negotiators incorporate certain rules into a regime and exclude others, they are making choices that have crucial implications for whether or not actors will comply.

For decades, nations have negotiated treaties with simultaneous hope that those treaties would produce better collective outcomes and skepticism about the ability to influence the way governments or individuals act. Both lawyers and political scientists have theorized about how international legal regimes can influence behavior and why they often do not.

States create international institutions in attempts to resolve problems they cannot solve alone. Yet states vary in their desire to form and join such institutions and in their incentives to defect from those they do join. These obstacles to cooperation have produced considerable variation in the mechanisms institutions use to deter defection without deterring participation. Some rely on narrow issue-specific reciprocity, whereas others rely on broader linkages involving coercive sanctions or positive rewards. This diversity in institutional scope is neither meaningless variation nor simple experimentation. Instead, states tend to base institutions on issue-specific reciprocity when possible but incorporate positive or negative linkage to other issue-areas when the distribution and enforcement problems within an issue-area appear more severe.

In an interdependent world one state's behavior often imposes unintended costs on other states. Yet, though all such negative externalities create demands for their resolution, all externalities are not alike. Some are symmetric, with all states being simultaneously victims and perpetrators. Others are asymmetric, with “downstream” states being victims of, or dissatisfied with, the externality and “upstream” states being perpetrators of it. Dissatisfied states may accept both types of externalities, or they may try to resolve them by force. But they often create international institutions to resolve them.

In symmetric externalities the fact that all states prefer mutual cooperation to the status quo predisposes states toward narrow institutions that rely on issue-specific reciprocity. Although coercion or side payments could also be used to combat incentives to defect, such linkage is usually unnecessary.