The growth of transnational environmental harm is not only leading to new obligations between states, it is also recasting democratic accountability for the crossboundary environmental performance of public and private actors. Informed by pragmatist ideas on public discourse, I propose a conceptual schema for understanding the moral geography of these new transnational environmental obligations: they mark out non-territorial spaces of public communication delimited according to moral precepts of harm prevention, inclusiveness and impartiality. I outline how the recognition of transnational affected publics is reconstituting and rescaling environmental accountability within international regimes of harm prevention and liability. The critical geopolitical challenge in institutionalizing non-territorial domains of environmental accountability will be the mapping and empowerment of transnational affected publics.