Using archival analysis, this article retraces the internationalization of natural disaster management from the time of the League of Nations up to the 1990s. The chosen examples (uis, unesco, undro, idndr) show that the environment and natural disasters are usually two clearly separate agendas. These international organizations have long dissociated their main goal — ad hoc assistance — from scientific research focused on prevention. Yet prevention activities are the reason these actors came to be interested in the environment in the first place, though an interest in environmental protection or in building a bridge between these two fields did not necessarily follow.