While the law of the sea is rightly viewed as the most suitable international legal regime for the settlement of disputes in the Arctic, the militarization of this region in an era of climate change is also observable. Yet curiously, scant attention has been paid to the constraints the international humanitarian law (IHL) would impose on armed conflict in the Arctic, as unlikely as such conflict may be. These constraints include the specific prohibition on causing widespread, long-term, and severe environmental damage under Additional Protocol I to the Geneva Conventions as well as the related obligation to have “due regard” for the natural environment, as referred to in, for example, the San Remo Manual on International Law Applicable to Armed Conflict at Sea. Similarly, environmental factors must play into military assessments of targets based on the general principles of IHL related to targeting. The authors explore how these various legal obligations could be applied in the Arctic context. Referring to the scientific literature, they suggest that, due to the particularly vulnerable nature of this regional environment, many traditional war-fighting techniques would lead to damage that is not legally permissible. This conclusion should provide an additional incentive to policy makers to demilitarize the Arctic and to solve peacefully any disputes that may arise over sovereignty, navigation, or resources.