The scope of protection of the environment in relation to armed conflict has continued to expand since the issue was first introduced on the international agenda in the 1970s. Today, it is recognized that the environment is a prima facie civilian object and as such it is entitled to the same layers of protection during an armed conflict as any civilian person or object. Thus, there is a legal obligation to prevent environmental harm in armed conflict, before the event. Given the magnitude of environmental damage that can be anticipated in relation to armed conflict, the obligation to prevent such damage in the first place is critical. In this regard, it is important to note that the legal obligation to prevent environmental harm originates from international environmental law. Furthermore, the obligation to prevent harm is an ongoing obligation. This article illustrates that the general preventive obligations found in international environmental law can shed much-needed light on the general preventive obligations already established under the law of armed conflict, in furtherance of environmental protection.