The existing literature underestimates the contribution of federated entities to international environmental agreements. This research note introduces a novel dataset on the role of federated entities in 2,077 environmental agreements. We demonstrate the value of this dataset by revisiting unexamined assumptions that stem from the literature. According to conventional wisdom, (1) federated entities’ participation in environmental agreements is a recent phenomenon, (2) this phenomenon is led by federated entities in Western democracies, (3) it has accelerated as a response to the climate crisis and (4) it is driven by the same movement that favours the participation of diverse stakeholders. This research note questions these preconceived ideas and illustrates how the new dataset sheds light on the role of federated entities in environmental governance.

Adaptation to climate change has traditionally been framed as a local problem. However, in recent years, adaptation has risen on the global policy agenda. This article contributes to the study of transnational climate adaptation through an investigation of international connectivity on climate adaptation between regional policy-makers. We examine the RegionsAdapt initiative, the first global commitment to promote and track the progress of regional adaptation. While adapting to climate change at the regional level is crucial, we suggest that transnational adaptation governance not only helps to promote adaptation measures, but also improves the process of tracking the progress of such action, its visibility and its aggregation.

The increasing importance of subnational governments in interstate affairs calls for international and comparative law scholars to take subnational foreign relations law more seriously. This article conceives this law as the legal rules that regulate the vertical allocation of foreign relations powers within and across States, and constructs an analytical framework that addresses the questions of why any sovereign would grant extensive foreign relations powers to constituent entities and how such an arrangement plays out in actual practice. This study takes a comparative approach to case studies of the Special Administrative Regions (SARs) of the People's Republic of China: Hong Kong and Macau, which are known for their unusually extensive paradiplomatic powers, which not only defy conventional categories but also surpass those of other substates.

Climate change is a global environmental problem which has been addressed primarily at the multilateral level. However, national, supranational, and even subnational action on the issue has also sprung up. At the subnational level, California (United States) and Acre (Brazil) offer an interesting example of how domestic policies may be linked in order to address climate change. Based on a memorandum of understanding concluded in 2010, these two states have been working towards the possible linkage of their respective climate change policies, in essence providing a pathway for using emissions offset credits that are generated in Acre through reductions of forest-based emissions in the Californian cap-and-trade programme. Taking into account that this is an ongoing process, this commentary provides a general overview of the issue from the perspective of international law.

Since the 1990s, a number of local and regional governments around the world have started to engage in a real international or ‘paradiplomatic’ climate agenda. While the multilevel governance approach has advanced the examination of the actors and levels involved in climate governance, there is within this body of literature a limited consideration of the legal capacity of non-state actors to act across scales. This article addresses this gap and examines the potential limitations imposed on subnational diplomacy by international and domestic legal orders. The article draws upon the example of Brazil where, despite constitutional limitations on the involvement of subnational governments in international relations, paradiplomacy has been termed ‘federative diplomacy’ and institutionalized within the Ministry of Foreign Affairs and within the Presidency of the Republic. The article shows that the diplomatic activity of local and regional governments is still constrained by international and domestic legal frameworks. If cities and regions are to help in addressing the inadequacies of the international climate regime, then domestic and international legal frameworks will need to further accommodate subnational diplomatic activities.