Inter-state litigation is a weapon employed by weaker states with limited diplomatic leverage over their bigger, more powerful opponents. An authoritative judgment may facilitate a settlement of some kind, whether directly, by further negotiation, or simply by legitimising the claims made. The LOSC was negotiated at a time when climate change was not yet part of the international agenda; however, it must be interpreted and applied with subsequent developments in international law and policy in mind. [---] This article will discuss the role that Part XII of LOSC may play in enforcing states’ obligations to protect and preserve the marine environment from the effects of climate change.