The article presents suggestions for most immediate primary education content supplement, based on a survey of differences and commonalities between neighbouring but developmentally diverse South East European countries, Croatia and Slovenia. We begin by discussing social influences shaping the delineation of competence in environmental science and geoscience in compulsory education, with special emphasis on the constrictions imposed by the rapidly warming unevenly developed planet. These also include concerns about educating citizens in the post-political and partially post-democratic state that arises as the side-effect of a contemporary Western technocratic ‘knowledge society’ under climatic pressure. The background against which those are assessed consists of a range of development indices of the two countries, and the comparative achievements of Croatian and Slovenian students in PISA 2006 science assessment. We report on the perceived commonalities and differences in curricular content of the two countries along the lines of selected value-based input-groups of the Schwarzin cross-boundary transformative education for sustainability model (Schwarzin, 2010) in Environment, Geography and Technology subjects. Given the concerns expressed at the outset and the of curricular documents, we suggest combining active citizenship education and systemic and futures thinking skills with compulsory environmental science and geosciences school content.