This masterclass provides insights into the way that the environmental humanities has developed internationally from cross-disciplinary conversations through interdisciplinary innovation to transdisciplinary interventions. Transdisciplinarity is here understood as research that is co-created with affected communities and non-academic knowledge-holders and is oriented towards socio-ecological transformation. Particular attention will be given to the distinctive development of the environmental (previously ‘ecological’) humanities in Australia from the early 2000s, where a transdisciplinary and decolonial ambition was evident from the start. Focussing on the cross-fertilisation and confluence of several lines of environmental enquiry from history, anthropology, philosophy, literary and cultural studies, and religious studies, the masterclass will explore especially the transformative potential of the new inter- and transdisciplinary field of multispecies extinction studies, as this developed in Australia and is now being practiced worldwide.