When it comes to the weather and climate, most of us think only about what is happening in the atmosphere. If we ignore the ocean, however, we miss a big piece of the picture: covering some 70% of the Earth’s surface, the ocean is a major driver of the world’s weather and climate.

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.



Every year, WMO and its United Nations partners on ocean issues celebrate World Oceans Day on 8 June.

How the ocean shapes weather and climate

The ocean’s tight linkage with the atmosphere makes understanding its behaviour vital for forecasting weather and climate conditions.

Forecasting climate variability

In addition to influencing the geography of the planet’s climate zones, the ocean causes the climate to vary over periods of weeks to decades through regular oscillations.

The ocean and climate change

Studying the ocean is essential for gaining a better understanding of human-induced climate change. 

Observing the ocean

Because the ocean is a global commons, strong international coordination is needed to ensure regular and sustained observation.

Ensuring safety at sea and on land

Better projections of how storm patterns will change, sea ice will melt and regional sea level will rise is vital for the improved safety of life and property at sea and for coastal zone management.

SDGs and other initiatives

WMO, National Meteorological and Hydrological Services and other national entities support international efforts to monitor ocean temperatures, currents, salinity, and sea surface levels – all major variables in understanding weather, climate and climate change.

FAQs - Ocean

Up to 90% of world trade is transported on ships. Ocean economic activities are forecast to increase rapidly, doubling in size from US$ 1.5 to 3 trillion by 2030. International cooperation and collaboration are key to finding impactful global solutions in support of the sustainability and safety of people, property and the planet. (Ocean Obs Report Card)

Supporting the safety of life and property at sea, integrated coastal management and the minimization of societal impacts from natural hazards through the provision of meteorological-ocean services.

Joint WMO-IOC Collaborative Board

Based on the recommendations of the Joint WMO-IOC Consultation Group on the Reform of JCOMM, Congress 18, through Resolution 9 (Cg-18), and the 30th IOC Assembly, through Resolution XXX-2, established the Joint WMO-IOC Collaborative Board.