Abstract
I believe that the phenomenon of regionalization that currently gains weight as a characteristic of the international system bears a great potential for increasing the effectiveness of complex international environmental regimes. Constituting a sub-level within the international system, macro-regions create a bridge between the anarchy of the international system and the order of the state, by doing so, allowing for a certain amount of intra-regional cooperation to emerge and facilitating inter-regional coordination. The corresponding fragmentation of complex environmental regimes into sub-regimes consisting of groups of states sharing certain characteristics and interests can be expected to contribute to an increase in their effectiveness.