September 18, 2019. Numerous approaches to understanding and responding to increasingly complex environmental health issues have proliferated over the past 150 years. Most recently, Planetary Health has emerged as a pre-eminent area of research and practice in the broader field of environmental health, defined as “the health of human civilization and the state of the natural systems that define the safe environmental limits within which humanity can flourish” (Whitmee et al. Rockefeller Foundation/Lancet Commission Report on Planetary Health, 2015). Planetary Health supposedly grew out of what is referred to as the ‘Planetary Health paradox’–the fact that humans are healthier than any previous point in history, but that our health and lifestyles are predicated on crisis-level overuse of resources and the related deterioration of ecosystem services that support all life on our planet. However, to date, there have been limited ethical interrogations of emerging environmental health perspectives (e.g. Ecohealth, One Health, Planetary Health), and a more comprehensive engagement with the ethics of an emerging field of inquiry will undoubtedly add value to the significance and impact of associated interventions and responses. In the case of Planetary Health, this would necessarily include explicating the scalar nature of ethical issues from the local to the global and across the past, present, and future. In this webalogue, our presenters will explore ethical issues that manifest across different scales, and outline a research program to build a theory for planetary health justice.