In this article we analyse how professionals in two international environ- mental organizations (IEOs) concerned with biodiversity act as ‘entrepreneurs of cosmopolitanization' by establishing connections between the various scales they mobilize in their daily work. Drawing on an empirical survey, we show that these professionals mobilize a range of activities to meet a twofold requirement. The first requirement is for universality, which corresponds to their status, their determin- ation to adopt a scientific approach and to the scale at which they initially defined the problem of biodiversity loss. The second requirement is to embed in specific contexts. Tension between these two types of requirement is inevitable. It is inherent in the cosmopolitan perspective and leads to contextual arrangements between the global approach to environmental problems and the forging of alliances with national, regional or local institutions and actors, according to opportunities and requirements. Connecting the various scales of environmental action unavoidably remains a partially achieved objective.