West European politics has been reshaped by the Education politicization of a new divide: environmentalism versus productivism. While existing scholarship since the 1960s mostly assumes the emergence of a single, unified cultural divide, this article goes back to the model developed by Lipset and Rokkan (Citation1967) and distinguishes two new cleavages, Ecologism/Productivism and Identity/Cosmopolitanism, both resulting from different revolutions. Building on Bartolini and Mair's seminal framework, this analysis also introduces a fourth dimension to the definition of cleavage: in fully mobilized electoral societies, it encompasses sociological, ideological, and organizational dimensions, as well as a policy-making component. The study then delineates and illustrates the core features of the Ecologism/Productivism divide with data on public opinion, party positions, and green parties' development. This conceptualization offers a new lens for political scientists and policymakers, illuminating how the environmental conflict reshapes societies and party systems, interacts with other ideological and social conflicts, and influences the trajectory of West European polities in the age of the Anthropocene.

Productivism is a socio-economic paradigm that emerged at the end of the 19th century, which establishes the continuous increase in productivity, production, and consumption as the primary goal of social organization. Conceptualized by Belgian chemist and industrialist Ernest Solvay, it involves rationalizing and intensifying all agricultural, industrial, and intellectual production processes in the name of material and social progress. From the 20th century onwards, productivism became the dominant, often implicit, framework structuring economic policies, technoscientific models, and collective imaginaries, regardless of political regimes, whether capitalist or socialist. Its detractors point out that productivism disrupts human relationships at work, with nature, and within the community. By relegating non-productive activities (care, civic engagement, creation) to the margins, it accelerates social rhythms, generates growing alienation, and exerts unsustainable pressure on socio-ecosystems.

Is Western environmentalism left-wing or right-wing? The question reveals profound ideological shifts. Emerging in the 1970s on the fringes of traditional political divisions, political ecology initially rejected the left-right divide, combining Third World, conservative, and Marxist influences. Although conservative environmentalist movements do exist, they remain marginal. In practice, green parties and environmental movements are mostly anchored on the left: economic regulation, social justice, and cultural openness. Electoral alliances (particularly in France) and citizen surveys confirm this trend. Today, environmentalism is even redefining what it means to be "left-wing," placing environmental issues at the heart of progress.