GTOS concept is its 2-way information flow: from the
national field sites to regional and global databases, as well as
the feedback to national sites in order to provide a wider
context for analysis of local measurements. Global
harmonization of GTOS measurements and data management
at all three levels is a high priority requirement. (Heal et al.,
eds., 1993; Tsai-Koester, 1994)
6. CONCLUSION
In spite of the spectacular advancement of the geomatics
information technologies of remote sensing, GIS and GPS, and
their growing integration in recent years, the opportunities to
fill the gaps in land cover information, and to establish a
systematic environmental monitoring system at regional and
global levels will not be realized by default. Their fulfillment
requires more effective international coordination in the
following four broad areas:
planning the relevant earth observation satellite missions;
standardization of satellite data formats and derived
products;
e establishment of effective and user-friendly RS data
archives and networks;
e planning and implementation of regional and global land
cover mapping and environmental monitoring programs.
While the first three areas are looked after by the international
Committee on Earth Observation Satellites (CEOS), the
international coordination of land cover mapping and
environmental monitoring programs at the regional and global
levels has not been satisfactory. There should have been more
effort to achieve complementarity between such programs and
thus to reinforce their impacts through effective coordination
and, when appropriate, cooperation.
The coordination should start with an international agreement
on harmonization of the central component of the regional and
global land cover mapping and environmental monitoring
programs, their comprehensive land information databases
(LIDs), in which all data resulting from these programs are
stored. (Section 4.2, Fig. 1). Their structures should allow
linkages, effective communication and exchange of data
between all regional and global land cover mapping and
environmental monitoring programs. Once this task has been
accomplished, a solid foundation for international coordination
between such programs is in place. It is proposed that the
UNEP-GRID takes up this challenge.
Referring to the land cover mapping programs, there is an
urgent need for international harmonization of the land cover
classification systems designed for the global and regional
programs; the scales, legends and formats of land cover maps;
accuracy standards, and dissemination of information.
Similarly, there should be harmonization of methodologies for
environmental monitoring at the regional and global levels. It
should include, in particular, the indicators to be monitored, at
which levels and with what accuracies, reporting intervals;
formats of data and derived products, and communication
systems. Last, but not least, the international harmonization,
in the context of regional and global land cover mapping and
environmental monitoring programs, should also include the
supporting field activities for collection of coherent ground
424
data sets. Such datasets are essential for the validation of RS
products; as a source of information which cannot be obtained
from RS data alone; and for derivation of field inputs to
mathematical models for assessments and forecasting.
CEOS has finally recognized the need for coordination of the
growing number of global EO programs and started
discussions on the development of Integrated Global
Observing Strategy (IGOS) at its first IGOS Workshop in
Seattle, USA, in March 1996. A good example of such
international coordination is the successful collaboration in
global meteorological observations by an international network
of geostationary satellites. The Workshop ended with a
consensus in support of the development of IGOS. The next
CEOS meeting on this subject will take place in Fall, 1996.
(CEOS, 1996; Embleton, 1996; Guertin, 1996).
The United Nations estimates an increase of population from
the current about 6 billion to about 9 billion by the year 2030.
Such an unprecedented increase of number of people during
the next 35 years demands mobilization of all our resources to
be able to assure adequate food supplies while preserving the
Earth's environment for future generations. We have the
technological means to achieve this goal. Up to now, the
overall food production has always kept pace with the
population increase. But ^ mankind has never faced a
population increase of 5096 in such a short time and in such
large numbers. Assuring the availability of reliable, timely and
affordable information on changes in land cover, land use and
land degradation at a global level, is part of the solution. Only
by joining our forces and mobilizing our efforts shall we
succeed in reversing environmental degradation and
establishing sustainable development and management of the
earth’s natural resources. There is no other alternative.
ACKNOWLEDGEMENT
The author gratefully acknowledges helpful comments by
reviewers of this paper, Dr. F.H.A. Campbell, Dr. J. Cihlar
and Mr. L. Whitney. Computer graphics assistance by Mr. R.
Shergold is also much appreciated.
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