In the context of the historical development of international humanitarian law (IHL), the specific protection of the environment is relatively recent. Still, in the almost fifty years since the first treaty rules emerged explicitly protecting the environment during armed conflict, modern understandings of the relationships among ecological and human health, on one hand, and the multi-layered and diverse threats that armed conflicts pose to the environment, on the other hand, have significantly advanced. This issue of the International Review of the Red Cross delves into the many ways that conflict can adversely impact the environment. The articles within it develop thoughtful analysis regarding how the existing international legal framework protects the environment during armed conflict.