2-1. Goals of NOPACCS

Among the problems concerning the global environment, the global warming due to carbon dioxide and other gases has called an international focus of attention to the discussion of (1) the clarification of the warming mechanism, (2) the evaluation of its environmental, social, and economic influences, and (3) the countermeasures to the warming. With these in the background, the New Energy and Industrial Technology Development Organization (NEDO) launched in the fiscal year 1990 its industrial technology research and development project on global environment under the financial and other assistance of the Ministry of International Trade and Industry (MITI). As a part of this project, Northwest Pacific Carbon Cycle Study (NOPACCS) was commenced in 1990 for a period of seven years. This project aimed at conducting researches on the absorption of CO₂ to the ocean and behavior and cycle of the carbon in the ocean.

World annual CO₂ emissions mainly from fossil fuel burning is about 7 Gt carbon per year (Gt C yr-1), and accumulation in the atmosphere directly measured from atmospheric CO₂ (about 370ppm at present) is only about 3 Gt per year. Among the remaining 4 Gt of carbon, about 2 Gt is speculated to have been absorbed mainly in the ocean. Also, the ocean is a large carbon reservoir, and total carbon in the ocean is more than 50 times as large as that in the atmosphere. Therefore, understanding the mechanisms of CO₂ absorption into the ocean and estimating its capacity as a carbon sink are important for conservation of global environment.

In order to quantitatively evaluate the carbon cycle in the ocean, a field survey was carried out to clarify physical circulation, biogeochemical processes and accumulation on the seafloor. Meteorological, oceanographical and biogeochemical information related to the carbon cycle was collected from the western North Pacific, because the survey areas include different climate and oceanic zones. Geological information was also collected to identify the long-term carbon accumulation on the seafloor.