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Given that the technical challenges will be met, the impact of remotely sensed 
information on environmental management will be determined primarily by policies gov 
erning the availability of remote sensing data to this application. Whereas there are 
promising developments in remote sensing data policy in selected situations, there remains 
a need for developed nations to seek and implement data policies and institutional 
mechanisms that are consistent with and provide support for wide-spread use of data from 
remote sensing Earth observing systems on environmental problems of global significance. 
The data policy issue becomes difficult particularly when: i) reasonably high 
resolution is required (much finer than that of AVHRR data, for example); ii) large areas 
are to be imaged, spanning perhaps several different countries and/or regions; iii) the data 
has less immediate value than cost to the potential user, even though the long range global 
benefit of the data may be demonstrably greater than its cost; and iv) data may be gathered 
only on request for regions of short run interest, consequently no global archive would be 
accumulated, even though future use of such data might become desirable if not essential 
for purposes of science or intervention. 
Overview 
This paper considers issues of remote sensing data policy in the context of active 
global environmental monitoring. The development begins with an examination in Section 
2 of the scale and importance of the problem, and a brief review of outstanding technical 
issues. Section 3 reviews the current market place approach to remote sensing data policy, 
and comments on aspects of the inconsistency of that policy with respect to the long range 
public interest. Section 4 notes several recent initiatives that would modify the purely 
commercial data policy in directions favouring large scale environmental monitoring. The 
paper closes with a recommendation that could lead to a remote sensing data policy more 
in keeping with our collective sense of global environmental responsibility. 
2. IMPLICATIONS OF GLOBAL MONITORING 
We assume that the issue of active global environmental monitoring is to be taken 
seriously, as recommended for example by the Stockholm Conference on the Human 
Environment (1972), the Brundtland Report [World Commission on Environment and 
Development, 1987], and the "Green Summit" of Paris, July, 1989. In spite of such 
recommendations, however, there has been little progress using high resolution sensor data 
beyond scientific studies and pilot projects. 
Need for Global Monitoring 
Through United Nations (UN) agreement, the mandate for tropical forest assessment 
has been given to the UN Food and Agricultural Organization (FAO) based in Rome. FAO 
undertook a global assessment of forests for 1980 (published in 1983), and is actively