The first twenty years of international negotiation on climate change took an approach that was guaranteed to fail: attempting to solve an immensely complex issue through a single, legally binding agreement. The history of diplomacy in trade and security shows that success requires a different approach: breaking a problem up into manageable parts, and growing agreement gradually, strengthening it as parties’ interests increasingly converge.

This chapter provides an overview of the drivers and the science of global climate change.

The author examines the interplay between the individual and collective dimensions of treaty-based law-making and standard-setting processes in the United Nations climate regime. The reason why the author attempts to do so is that multilateral treaties have been the main anchors for international environmental law-making. In this context, State consent not only has individual effects, but also feeds into a collective process. The chapter begins by exploring the United Nations Framework Convention on Climate Change and the Kyoto Protocol. It then turns to the Paris Agreement and the shift to what has been described as a ‘bottom-up’ approach. The perhaps most striking feature of this approach is its reliance on non-binding, ‘nationally determined contributions’ (hereafter NDCs). From the vantage point of State consent, the most significant consequence of the Paris Agreement’s NDC approach is a shift away from the anchoring of consent to climate action in treaty-based processes, and hence from the linkages that adoption and entry-into-force requirements establish between multiple parties’ individual expressions of consent.

Climate change is a profound global concern. The burning of fossil fuels for energy production has increased emission levels of greenhouse gases such as carbon dioxide into the earth’s atmosphere, generating an increase in global warming of around 1.1 degrees Celsius. Net global anthropogenic GHG emissions are increasing across all major sectors as a result of rising global activity in industry, energy supply, transport, agriculture and construction. This is contributing to changes in the earth’s climate, such that global average temperatures have risen considerably since measurements began in the mid-19th century, affecting weather patterns and sea levels.

The first twenty years of international negotiation on climate change took an approach that was guaranteed to fail: attempting to solve an immensely complex issue through a single, legally binding agreement. The history of diplomacy in trade and security shows that success requires a different approach: breaking a problem up into manageable parts, and growing agreement gradually, strengthening it as parties’ interests increasingly converge.

How have states coordinated their response to protecting the environment? This chapter outlines the major features of international environmental law, beginning with a brief history of global environmental governance.  We begin with a broad outline of the major environmental conferences, culminating in the architecture of climate change governance. While climate change is a focus of this chapter, we also highlight some of the other major environmental achievements related to protecting the marine environment, regulating atmospheric pollutants, and preserving biodiversity.  Core environmental law principles are detailed and illustrated with prominent cases for clarity.  The final sections examine the intersections between human rights, armed conflict, and the environment, concluding with a discussion of the impact of corporations on the global environment and the responsibilities they might bear for restoring it.

This chapter introduces the concept of networking of carbon markets and analyses the political, legal and practical reasons for using networking as opposed to linking. It also considers how the application of DLT can help to operationalise a networked carbon markets framework.

Magnificent piece of statecraft though it is, the Paris Agreement is unlikely to spare us from a future climate reckoning. Paris can be seen as the successor to a series of prior global emissions limitation agreements including the breathtakingly effective Montreal Protocol that addressed the cause of the “ozone hole” and the Kyoto Protocol, the world’s first attempt to address climate change. Kyoto collapsed in failure and Paris was therefore midwifed with the Kyoto lessons in mind. We then delve into the structure, status, and limitations of the Paris Agreement before looking ahead to how it might evolve.

Though relatively young, the climate regime has already exhibited a profound transformation. “Old governance”, embodied by the Kyoto Protocol, was largely state-focused and hierarchical. The 2015 Paris Agreement represents “new governance,” with an emphasis on transnational actors and bottom-up approaches. The bet is that new governance is better suited to both the realities of domestic politics and profound uncertainty surrounding climate change than the old governance model. If we are correct, then we have created the enabling conditions for decarbonization. The question is: will it happen fast enough? The answer to this question is critical both for the future of the planet and the legitimacy of global governance. Climate change will likely exacerbate existing problems in world politics such as armed conflict and mass migration. Worse still, those least capable of adapting to a changing climate will be most affected. A shift to a “new” global governance architecture means little if climate change continues apace. To preserve the legitimacy of the climate regime, as well as much of the fabric of the current liberal international order (such as it is), actors will have to move more swiftly and decisively toward a fossil-free world.

Pamela Chasek, Professor at Manhattan College and co-founder and executive editor of the Earth Negotiations Bulletin, places the Paris Agreement in its historical context by reviewing the origins and development of the climate change regime. The chapter describes the history of the UNFCCC, from its creation in 1994, through the 1997 Kyoto Protocol, over key milestones in the discussions about a post-Kyoto successor regime. The chapter traces climate negotiations over a series of COPs, including the divisive debates at the Copenhagen COP in 2009 and the efforts to rebuild the parties’ trust in the process during the following years. It details how negotiations in the 2010–14 period led countries to converge around a bottom-up arrangement for the post-2020 regime. While many contentious issues remained unresolved as negotiations entered the home stretch in 2015, Chasek describes how the French Presidency of COP 21 sought to prepare the ground for a compromise agreement, both before and during the negotiations in Paris, ultimately succeeding in bringing the parties together in support of an agreement that “represents an evolution in climate governance”.

This chapter debates the significance of the principle of common but differentiated responsibilities and respective capabilities in the light of different national circumstances (CBDR-RC+). A top-down determination of state responsibility based on an objective assessment, as in the case of the Kyoto Protocol, which created two main categories of states, has proved controversial, due to the existence of alternative theories of differentiation. All of them seem to have been mashed up together in CBDR-RC+. Thomas Leclerc develops the argument that the principle has now become legally meaningless, as it does no more than invite each state to determine its own contribution to climate action, entirely free from external review, which is something we hardly need a new principle for. But there is also the argument, articulated by Daria Shapovalova, that CBDR-RC+ remains central to the UNFCCC regime, and can influence the direction of the negotiations, as well as litigation outcomes.

This chapter debates the significance of the principle of common but differentiated responsibilities and respective capabilities in the light of different national circumstances (CBDR-RC+). A top-down determination of state responsibility based on an objective assessment, as in the case of the Kyoto Protocol, which created two main categories of states, has proved controversial, due to the existence of alternative theories of differentiation. All of them seem to have been mashed up together in CBDR-RC+. Thomas Leclerc develops the argument that the principle has now become legally meaningless, as it does no more than invite each state to determine its own contribution to climate action, entirely free from external review, which is something we hardly need a new principle for. But there is also the argument, articulated by Daria Shapovalova, that CBDR-RC+ remains central to the UNFCCC regime, and can influence the direction of the negotiations, as well as litigation outcomes.

This chapter describes the basic features and lasting influence on climate governance of the international system of states. When the problem of climate change became apparent, countries responded to it through diplomacy leading to international agreements for collective action. This chapter describes major aspects of this process. It summarizes how countries have negotiated a regime of international agreements and institutions intended to address climate change collectively and individually. A quarter-century was devoted to top-down measures – internationally agreed conventions and protocols setting out allowable greenhouse gas emissions for individual countries. More recently, the focus has been on bottom-up measures – nationally determined contributions to wider global efforts to govern climate change. While these efforts have resulted in a wide array of actions around the world to address climate change, they also demonstrate concretely the ways in which the international system, and the countries operating within it, have precluded aggressive collective action.

Reducing greenhouse gas emissions is a global collective action problem but humanity lacks a global government. A global government would create a mandatory compliance mechanism because this is the only way to incentivize a successful global effort. For almost three years, national governments have instead tried to reach a voluntary agreement in which countries agree on a fair allocation of the emissions reduction and the burden of costs. This has predictably failed and will continue to fail. The only hope for success is if some leading countries take domestic actions and apply carbon tariffs on imports from high-emission countries. These leading countries should try to join forces in “climate clubs” which, as they grow in economic importance, would motivate more countries to join, eventually reaching a tipping point for the development of a global compliance mechanism.

Because of its transboundary effects and because states will be the primary actors, large-scale solar geoengineering and its governance are matters of international law. This is the second of four chapters that consider international legal rules, here regarding the climate and the atmosphere. Climate change is, and solar geoengineering would be, foremost atmospheric phenomena. The UN Framework Convention on Climate Change and its protocols – the central legal regime for international cooperation to limit climate change and its impacts – offer surprisingly limited guidance for solar geoengineering. However, the regime could provide an institutional site for future multilateral governance. Some provisions of the Vienna Convention for the Protection of the Ozone Layer and the Convention on Long-Range Transboundary Air Pollution (and their protocols), which regulate substances that contribute to stratospheric ozone depletion and to acid rain, respectively, would be applicable, depending on circumstances. The International Law Commission has approved Draft Guidelines on the Protection of the Atmosphere, one of which addresses activities aimed at its intentional large-scale modification.