no regional recordings of Soviet nuclear explosions were available, nor were Soviet recordings of U.S. or other countries' test explosions. Now there is access to large amounts of these data by scientists outside the former Soviet Union. Other types of Soviet Earth science data, such as gravity and magnetics observations and Arctic oceanographic observations, also have been made available to the scientific community. 43 Likewise, U.S. data from some previously classified observational programs, including reconnaissance satellites44 and undersea sensors, 45 have been made publicly available. The international availability of useful Earth science data has increased significantly with these data declassifications, and the committee encourages all governments to undertake similar reviews of classified retrospective data sets.
A striking example of the benefits of extensive data collection and research for international management of environmental problems is evident in agreement by the nations of the world on a clear strategy for mitigating depletion of ozone in the stratosphere.46 Not only was agreement reached in a limited period of time, but substitute substances and technologies also have been developed rapidly without a large economic impact on society.
Unfortunately, not all of the many global environmental and health problems can be confronted in the same way as was done for stratospheric ozone. In fact, many of the underlying research issues are extremely complex and interrelated. In the case of reducing the uncertainties regarding the much publicized global warming trend, extensive geophysical and biological data on the atmosphere, ocean, land surface, and cryosphere will be required on a global basis for long periods of time. The role of the ocean in the global carbon cycles and in the energetics of the atmosphere, the impacts of deforestation and decertification, the full implication of the radio actively active gases, and a host of interrelated natural processes need to be understood. Such understanding can be gained only by acquiring and analyzing comprehensive data sets on a global basis, with the active involvement of most, if not all, nations, and with the best efforts of the world's scientific community. But we do know from the stratospheric ozone problem that international agreement can be reached when adequate data and understanding of the problem are available to policymakers throughout the world. It is therefore essential that environmental and health data and information capable of describing our global atmosphere, ocean, and terrestrial system be fully and openly available. Moreover, making such basic data broadly available is fundamental to ascertaining the veracity and validity of the scientific process and of the resulting conclusions. If the data supporting the conclusions are not readily