Does humanity's future lie in the ocean? As demand for resources continues to grow and land-based sources decline, expectations for the ocean as an engine of human development are increasing. Claiming marine resources and space is not new to humanity, but the extent, intensity, and diversity of today's aspirations are unprecedented. We describe this as the blue acceleration—a race among diverse and often competing interests for ocean food, material, and space. Exploring what this new reality means for the global ocean and how to steer it in a sustainable and equitable way represents an urgent challenge.