In this volume, Mark Douglas offers a new vision of the history of Christian pacifism within the context of a warming world. He narrates this story in a way that recognizes the complexities of the tradition and aligns it with a coherent theological vision, one that shapes the tradition to encompass the new causes and types of wars fought during the Anthropocene. Along the way, Douglas draws from research in historical climatology to recover the overlooked role that climate changes have always played in shaping not only the Christian pacifist tradition but also the movement of traditions through western history. Scholars across a range of disciplines - peace studies, Christian theology and history, environmentalism, and environmental conflict studies - will benefit from this model of critical and charitable engagement with the complex history of Christian pacifism, the resources of which will be important for addressing wars in a warming world.