Given the challenges facing the world in the field of environmental policy, research on complex interdependencies in world politics and transnational policy-making has intensified. Several institutions have came into existence in response to the increasing concerns about global climate change. This paper analyzes the structure of the parties involved in regulating climate conventions and treaties, and designs instruments for allocating responsibility to them. In order to point out the possibilities of allocating responsibility, the relationship between power and responsibility is examined. By applying power measures, we estimate the impact of the various agents in these contractual or instrumental arrangements taking a priori unions into consideration. We examine the United Nations Framework Convention on Climate Change and the United Nations Convention to Combat Desertification. Depending on the decision topics, developing countries can hold more power and responsibility than developed countries. B oth conventions refer to responsibilities of the parties as common but differentiated responsibilities. The primary responsibilities and thus power should fall to the industrial countries which is not reflected in our calculations.