Our ocean plays a major role in climate regulation, hosts vast biodiversity, sustains economies, ensures food security, and supports international shipping, tourism, recreation, and human health and security. Yet, the ocean is experiencing unprecedented changes: sea level rise, coral bleaching, ocean acidification, anoxia, accelerated melting of the major ice sheets, shifts in ocean circulation, pollution, overfishing, and increased industrialization. Sound plays a vital role in exploring, understanding, and monitoring these changes over a range of spatial and temporal scales. In this talk, I will focus on the multitude of approaches taken to using sound to understand our changing ocean, the advances in platforms used to enable these studies, the expansion of global ocean observing systems that include measurements of sound as an essential ocean variable, and the enormous complexities in interpreting acoustic signals in a dynamic and evolving ocean landscape. I will end by discussing the opportunities and obstacles associated with globalizing approaches for using sound to improve ocean stewardship.