Formalizing knowledge on international environmental regimes: A first step towards integrating political science in integrated assessments of global environmental change

International environmental regimes are considered key factors in dealing with global environmental change problems. It is important to understand if and how regimes are effective in tackling these problems, which requires knowledge on their potential impact on these problems as well as on their political feasibility. Integrated assessments of global environmental change, which are mainly bio-physical and technology-economic oriented, barely address knowledge on environmental regimes, due to problems in drawing general and policy relevant lessons on regime effectiveness and inherent difficulties in modelling human and social dimensions. This paper presents an innovative approach to formalize knowledge on the effectiveness of environmental regimes, so that scientists from both the political science and integrated assessment domain can understand it, discuss it and contribute to it. We constructed a conceptual framework for the systematic analysis of conditions that influence regime effectiveness and implemented it in a computer model using fuzzy logic methodology. We evaluated the fuzzy model in an ex post case study on four existing international environmental regimes. The model can be used as an aid in analysing the effectiveness of existing or future regimes, highlighting which determinants contribute to success or failure, and it enables systematic and meaningful comparisons between regimes and policy measures.We discovered that formalizing knowledge on environmental regimes in a framework and model enhanced its transparency and deductive power as it forced us to be explicit about our choices and assumptions. Developing and using the framework and model also revealed the lacunae in knowledge in environmental regime theory which may inform regime researchers to further structure and increase their knowledge. By making knowledge on environmental regimes explicit and understandable we have taken an important step towards a better integration of political science in integrated assessments. We believe, however, that this integration is still in its early days and requires further attention in the future. © 2012 Elsevier Ltd