ABSTRACT
The number of international regimes, private regimes, and organizations has grown exponentially over the past decades, both in the sphere of the environment and beyond. Consequently, most environmental issue areas are now co-governed by multiple institutions. This institutional proliferation has led to the emergence in the 2000s of a new field of research within global environmental governance studies dealing with “institutional interactions,” situations in which one institution affects the development or performance of another institution (Oberthür and Stokke 2011). We address here so-called “horizontal interactions” (Young 2002) between international institutions (and do not cover vertical interplay across different scales).
