Taking the Pulse of the Oceans

Science  15 Dec 2006:
Vol. 314, Issue 5806, pp. 1657
DOI: 10.1126/science.1135358

Keith Alverson

D. James Baker

Understanding human impact on the global environment requires accurate and integrated observations of all of its interconnected systems. Increasingly complex models, running on ever more powerful computers, are being used to elucidate dynamic links among the atmosphere, ocean, earth, cryosphere, and biosphere. But the real requirement for integrated Earth system science is a systematic, sustained record of observations, starting from as early as we can get quantitative information and extending reliably into the future. In particular, the ocean is critically undersampled both in space and time, and national and intergovernmental observational commitments are essential for progress.

Ocean basins cover most of the planet and are filled with circulating turbulent fluid whose behavior can be modeled only by approximation. For instance, we talk of a “conveyor belt,” but this is an unrealistic cartoon of actual turbulent circulation, which by transporting heat and fresh water affects the planet's climate. Knowledge about the true variability of the circulation remains elusive because long-term systematic observations are lacking.

Any seafarer knows that although one can look up from the deck of a ship and see the Moon clearly through 100 km of atmosphere, one cannot look down and see further than 1 m. Because the ocean is opaque to all wavelengths of electromagnetic radiation, Earth-observing satellites can't see below the surface either. Thus, much of the ocean must be observed from a patchwork of drifting and moored buoys, neutrally buoyant floats, coastal installations, and ship-based measurements.


Great recent progress has been made with each of these individual observing-system components. The launch of the 1250th drifting surface buoy in Halifax Harbor last year completed a network that is vital for tropical storm track prediction. The rapidly expanding international network of Argo floats has rewritten our knowledge of the temperature and salinity of the upper oceans. Moored buoy arrays in the tropics have made seasonal climate and El Niño prediction a real possibility. With tide gauges reporting in real time, not only can we predict coastal inundation hazards, but we can also disentangle the myriad processes involved in changing global sea level. Although observing the ocean is challenging, in particular cases it can be done well.

For 15 years, a global ocean-observing system under the auspices of the Intergovernmental Oceanographic Commission (IOC) of the United Nations' Educational, Scientific, and Cultural Organization (UNESCO) has been meeting important needs of global society. However, surprisingly little progress has been made toward a truly global system with long-term funding commitments. Lacking such a system and commitments, critical scientific hypotheses will remain untested.

The IOC is now working with the Global Earth Observation System of Systems (GEOSS) to identify national focal points for ocean observation efforts and to integrate these efforts into a truly global system. Unfortunately, there is still no plan for sustaining individual measurement programs, for integrating them into a coherent observing system, or for supporting them with stable funding. With a few notable exceptions, substantial multilateral government support for coordination and integration remains elusive.

To address this flaw, we propose the development of a UNESCO convention that commits nations to sustaining an integrated ocean-observing system that will lead to better understanding of the ocean and at the same time enable the provision of hazard warnings, monitoring of climate change, and management of marine and coastal resources. UNESCO's IOC stands ready to broker the development of such a convention. Preliminary discussions, including completion of the initial GEOSS tasks in ocean observation, begin at the next meeting of the Intergovernmental Committee for the Global Ocean Observing System in June 2007 in Paris. Will your nation be at the table?

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