1. Introduction

Of all areas of law relevant to and affected by climate change it is public international law that has historically been the most important. It is through public international law, also known simply as ‘international law’, the law that regulates relationships between sovereign states, that governments have initially sought to address climate change. This is seen primarily in the adoption of the 1992 United Nations Framework Convention on Climate Change (‘UNFCCC’)^[1] and subsequent treaties under this framework, most notably the 2015 Paris Agreement on Climate Change (‘Paris Agreement’).^[2] Collectively we can refer to this area of international law as the ‘climate regime’ or ‘international climate law’.

As will be discussed in this chapter, the climate regime is essential for addressing climate change, but it is also beset by fundamental limitations, several of which are a product of the nature of the international legal order. However, the climate regime is not the only field of international law relevant to climate change. Indeed, one of the key lessons of climate change, along with other global changes to the Earth’s systems, is that it touches upon multiple areas of international law, especially those dealing with other environmental issues such as the 1992 Convention on Biological Diversity (‘CBD’).^[3]

The chapter begins with an overview of the structure and organising principles underlying international law and its relevance for Australian law, before turning to assess the content of the climate regime and other complementary rules and principles of international law. The chapter then considers future potential trajectories for this area of the law and highlights some key issues that need to be addressed. The chapter invites readers to question the ways in which international law could more effectively address the climate crisis.