This chapter is concerned with how a claim to global authority over land and resources in the Global South has been invoked and the shape or form it has been given. It shows how the designation of both climate change and tropical deforestation as matters of ‘common concern’ has operated to authorise global authority over activities within national states that contribute to these processes. It interrogates how climate change has come to be understood in specific ways as an ‘object’ or ‘problem’ for law, and how this has given a distinctive shape to the climate regime. Finally, although forests have historically been subject to competing claims of international, national and local ownership, it shows how the focus on the capacity of forests to sequester carbon and function as carbon sinks has made it possible for the issue of deforestation, and thus also forest management, to be understood as a matter of global, rather than simply local or national, concern.