Climate change is an urgent threat to perinatal and infant health, with the greatest effects of climate change exposures being felt disproportionately by global majority communities who have been most harmed by systems of oppression. Human milk feeding is one recognized solution to bolster climate resilience. Yet, policies and practices to support human milk as a climate solution are inconsistent and under-prioritized, which is unsurprising given the lack of alignment between human history and current cultural context with regard to lactation and human milk access. This paper presents a new framework on lactation as a climate solution, which is unique in its incorporation of the critical history of cooperative breastfeeding in our species. Rooted in anthropogeny, or the study of human origins, and antiracist principles of lactation, the Allomilk Framework highlights five concepts of the ideal application of human milk as a climate solution, bridging ancient allonursing with present-day lactation and human milk access. These ideal applications-and the proposed development of measures to operationalize them-will advance the field through a shared understanding of the qualities that should be prioritized in the assessment of policies and practices at the intersection of climate resilience and human milk access. Application of the Allomilk Framework to assess and design future policies and practices will advance the field by increasing the potential for climate resilience and climate mitigation while working with-rather than against-the importance of cooperative breastfeeding in human history.