Covering some 70% of the Earth’s surface, the ocean is a major driver of the world’s weather and climate. It also plays a central role in climate change. The ocean is also a major driver of the global economy, carrying more than 90% of world trade and sustaining the 40% of humanity that lives within 100 km of the coast. Recognizing this, National Meteorological and Hydrological Services and researchers regularly monitor the ocean and how it is changing, modeling how it affects the atmosphere and delivering a wide variety of marine services, including supporting coastal management and Safety of Life at Sea. Today, the growing impacts of climate change are making ocean observations, research and services more critical than ever before.