If humanitarian tragedies caused by war have for a long time been the object of legal regulation, it was not until recently that the protection of the natural environment in armed conflict has attracted similar attention. The consequence is that there is yet no homogenous body of law that protects the ecosystem from hostilities. Apart from a few rules specifically addressing environmental warfare, indirect protection derives from provisions that were conceived for other purposes and from the underlying principles of customary international law that traditionally regulate the conduct of military hostilities. This raises the problem of the adequacy of the existing rules to protect the natural environment from warfare. In order to answer this question, the present chapter will first examine the rules available in the laws of war and will distinguish those specifically addressing the natural environment from other rules that might however apply and provide some protection. Individual criminal responsibility for the violation of such rules will then be discussed. In the second part, the chapter will investigate whether the law of peace, in particular international environmental law, can play any role in the protection of the environment in time of armed conflict and will verify its applicability pendente bello.