ABSTRACT The conflicts between protecting the environment and pursuing conventional political objectives concerned with rising GNP, employment, etc. are increasingly influencing decision-making processes and scientific debate. For sociology this results in a new area of research that focuses on the consequences and impacts of environmental concerns. One basic aspect of an Environmental Sociology is concerned with the re-ordering of societal alliances. In order to do so, the article introduces some elements of a cognitive network approach. Environmentalism, advanced by collective actors such as environmental organizations, promotes alternative models to productionist politics. By doing so, these actors are challenging the alliance between labour and capital. In an empirical study of the debate on nuclear energy the paper focuses on the challenge that environmentalism has posed to the consensus between labour and capital in Sweden and Germany. The results show striking differences between both countries. Moreover, the analysis arrives at the conclusion that environmentalism may not only challenge the consensus between labour and capital but may also lead to a new cleavage within the labour movement. [ABSTRACT FROM AUTHOR]