There are three key deficiencies in the existing body of international humanitarian law (IHL) relating to protection of the environment during armed conflict. First, the definition of impermissible environmental damage is both too restrictive and unclear; second, there are legal uncertainties regarding the protection of elements of the environment as civilian objects; and third, the application of the principle of proportionality where harm to the environment constitutes 'collateral damage' is also problematic. These gaps present specific opportunities for clarifying and developing the existing framework. One approach to addressing some of the inadequacies of IHL could be application of international environmental law during armed conflict. The detailed norms, standards, approaches, and mechanisms found in international environmental law might also help to clarify and extend basic principles of IHL to prevent, address, or assess liability for environmental damage incurred during armed conflict.