Most research on global governance has focused either on theoretical accounts of the overall phenomenon or on empirical studies of distinct institutions that serve to solve particular governance challenges. In this article we analyze instead "governance architectures," defined as the overarching system of public and private institutions, principles, norms, regulations, decision-making procedures and organizations that are valid or active in a given issue area of world politics. We focus on one aspect that is turning into a major source of concern for scholars and policy-makers alike: the "fragmentation" of governance architectures in important policy domains. The article offers a typology of different degrees of fragmentation, which we describe as synergistic, cooperative, and conflictive fragmentation. We then systematically assess alternative hypotheses over the relative advantages and disadvantages of different degrees of fragmentation. We argue that moderate degrees of fragmentation may entail both significant costs and benefits, while higher degrees of fragmentation are likely to decrease the overall performance of a governance architecture. The article concludes with policy options on how high degrees of fragmentation could be reduced. Fragmentation is prevalent in particular in the current governance of climate change, which we have hence chosen as illustration for our discussion. (c) 2009 by the Massachusetts Institute of Technology.

Governance responses from the international climate regime have been widely critiqued. But fresh research is revealing that ‘new’ and more dynamic forms of governing are appearing in alternative domains, producing a more polycentric pattern. Some analysts believe that these ‘new’ forms will fill gaps in the regime, but this optimism is based on untested assumptions about their diffusion and performance. We conclude that the advent of more polycentric governance does offer new opportunities to govern climate change, but based on existing empirical research it is far too early to judge whether hopes about the performance of the ‘new’ forms are well founded. More time and vastly more coordinated research efforts are needed to comprehend their full potential; time that is in very short supply in governing climate change

As countries negotiate a new climate agreement for the United Nations climate conference in December 2015, a groundswell of climate actions is emerging as cities, regions, businesses and civil society groups act on mitigation and adaptation, independently, with each other and with national governments and international organizations. The Paris conference provides a historic opportunity to establish a framework to catalyse, support, and steer these initiatives. Without such a framework, 'bottom-up' climate governance runs the risk of failing to deliver meaningful results. Social science research highlights the need for a comprehensive approach that promotes ambition, experimentation and accountability, and avoids unnecessary overlaps. This article specifies functions and design principles for a new, comprehensive framework for sub-and nonstate climate actions that could provide effective coordination.

This article introduces a special issue on the expanding research agenda on institutional fragmentation. The term refers to the growing diversity and challenges to coordination among private and public norms, treaties, and organizations that address a given issue area of international politics. International relations scholars increasingly address this phenomenon, framing it with alternative concepts like regime complexes or polycentricity. A considerable part of the existing debate remains focused on whether a centralized or polycentric governance architecture is preferable. Instead, as this special issue shows, domains of global environmental governance—like climate change, biological diversity, renewable energy, and forestry—are already fragmented. It is time to address new, more pertinent questions and help advance institutionalist research on this phenomenon. We introduce four major research themes for analyzing the fragmentation of different domains of global environmental governance: taking stock, causes, consequences, and responses.