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Ocean and Climate : The Delicate Balance


© N. Tiget/CNRS Photothèque

Nicole Papineau, INSU Deputy Scientific Director.

The oceans, which cover 70% of the Earth's surface, play a fundamental role in the stability of our planet's climate. This is where energy transfers take place, since the ocean is a reservoir of heat and carbon. Ocean and climate thus make up a dynamic, ever-changing system, and one which is today seriously affected by human activity and the resulting global warming.

Climate change makes it likely that coastal areas and low-lying land will be confronted by the threat of rising sea levels, while polar regions and their ecosystems will be affected by the increased melting of ice caps. Ecosystems will be affected by alterations in ocean currents, temperature, and salinity, among other factors. Such changes constitute major problems at a time when a large and increasing part of the world's population lives in coastal areas and depends on its resources. Major environmental issues surround not only coastal management, pollution, and fishery resources, but also natural catastrophes.

These issues confer an even greater responsibility on the scientific community, which has made much progress in our understanding of oceans over the past decades. Now, to apprehend the role oceans play in the climate system, we need to understand some of their characteristics such as currents and changes in salinity and the biological components. This is the goal of oceanography, whose first task is observation, which then allows scientists to construct models and make predictions. For many years, it was only possible to make scattered, isolated surface observations. But oceanography has undergone a major revolution with the advent of satellite altimetry which, for the first time, enables us to gather data on all oceans and measure their topography (sea levels, surface temperatures, etc.). However, oceanographic missions are still necessary, since they complement satellite observations with a study of the ocean below the surface layers and enable researchers to gauge parameters that cannot be measured by other means. At the same time, advances in modeling technology via increased computing power has improved our understanding of climate by taking into account interactions between the atmosphere and the ocean.

Oceanographic research requires an interdisciplinary approach involving physicists, biologists, and chemists. This is why it is now primarily organized through international programs such as WCRP (World Climate Research Program) or IGBP (International Geosphere Biosphere Program), to mention but two. In France, research is mainly carried out within the framework of the National Institute of Earth Sciences and Astronomy (Institut national des sciences de l'Univers, INSU) at CNRS, which can structure and finance this kind of activity via coordinated programs and large-scale experiments. These are often administered in partnership with other French bodies such as the Research Institute for Marine Resources (Ifremer), the Naval Oceanographic and Hydrographic Service (Service Hydrographique et Océanographique de la Marine, Shom), the Research Institute for Development (Institut de Recherche pour le Développement, Ird), the National Center for Space Studies (Centre national des études spatiales, Cnes), and Météo France, the French weather center. This research is carried out using ocean-going vessels and equipment managed by Ifremer and the Institut Paul Emile Victor (IPEV), and by INSU's coastal fleet.

As you will see through our extensive feature on oceans and climate (p.18), France, and CNRS researchers, are extensively involved in all the various aspects of oceanographic research. The many questions raised, and the (all too few) answers that we have, can help us grasp the extent of the threats that hang over the delicate balance between oceans and climate.



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