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on the face of the Earth -- large and small -- be it a space power or not.

Our goal is to obtain a scientific understanding of the entire Earth system on a global scale by describing how its component parts and their interactions have evolved, how they function, and how they may be expected to continue to evolve from decade to decade and even from century to century.

This is an enormous challenge. We must develop the capability to predict those changes that will occur in the next decade and well into the next century, from both natural causes and in response to human activity. This will require an integrated understanding of the entire Earth system where changes are likely to occur in periods of time spanning a decade or longer. And, as you know, that includes the land, the atmosphere, the oceans - i.e., the Earth's systems.

Therefore, global, synoptic and long-term measurements must be made. These measurements must involve simultaneous observations of the Earth's interactive natural and human processes, using spaceborne sensors to be complemented by Earth-based instruments and a new generation of information-processing systems.

Many nations of the world are already observing the Earth from space, or preparing to do so, to a degree we could hardly have imagined three decades ago.

In the United States, for example, NASA has long had an aggressive program of Global Earth Sciences. NASA developed the orbiting capabilities which form the basis of the United States' NOAA and GOES operational satellites and the LANDSAT land remote sensing satellites.

Geostationary weather satellite systems have been developed by Japan, Europe and India, with GMS, Meteosat and INSAT, respectively. The Soviet Union, France, Japan and India now have remote sensing spacecraft. ESA, Canada, Germany, Italy, Brazil, China and others are developing satellites or instruments.

NASA is now orbiting the Nimbus 7 and Earth Radiation Budget, or ERBS, research satellites. Nimbus is providing global data on stratospheric ozone, sea surface and sea ice variables. And ERBS is furthering our understanding of the balance of radiation input and output between the Earth and space - a balance which is key to improving our understanding of climate.

Beyond these ongoing missions, NASA will be doing much more in the area of Earth Science and Applications in the near future. And many of our activities will be cooperative efforts with other nations.

Three NASA missions to be launched in the early 1990's will address key aspects of the Earth as a system. Each will study a particular environment or region for a few years. Each will involve international cooperation. Thus, taken together, these missions are the building blocks of a comprehensive understanding of Earth as a system and will provide the scientific foundation for future international cooperation.

The first program is the Upper Atmosphere Research Satellite, or UARS. UARS will provide the first comprehensive measurements of the interplay of and among dynamic, radiative and chemical processes in the stratosphere and mesosphere. As you know, recent research led by NASA in the Antarctic underlined the importance of these measurements, which determine the extent and durability of the ozone layer. The UARS instruments are from the U.S., the U.K., Canada, and France, and the data will be analyzed by an international team of scientists.

The second NASA program is a Scatterometer that we are developing for global measurement of sea surface wind velocity. We are now proposing to fly this instrument on a Japanese Advanced Earth Observing Satellite (ADEOS) in 1993.

The third near-term program is a joint U.S.-French ocean topography experiment called TOPEX/POSEIDON. This mission, to be launched aboard the European Ariane rocket, will provide the first detailed measurements of the ocean's global circulation patterns, including the manner by which strong poleward currents, such as the Gulf Stream, are balanced by equatorward flow. Thus, it will permit a fundamental breakthrough in understanding the overall oceanic system functions.

TOPEX/POSEIDON, as well as ESA's remote sensing satellite mission, ERS-1, are planned to be coordinated with extensive world-wide oceanographic field experiments scheduled to be conducted in the early 1990's by the World Climate Research Program of the World Meteorological Organization. Clearly, all of these efforts will lay the foundation for a continuing program to provide long-term observations of oceanic circulation and its variability.

The world user community will have access to data from the three future NASA missions I've just described, just as it has had access to data from NASA missions in the past. Similarly, all of us are benefiting from access to data from SPOT and from Japan's Marine Observations mission, MOS-1. And the user community looks forward to data from India's IRS-1 mission, from Soviet remote sensing instruments and from the many remote sensing missions being developed for flight in the early 1990's.

But the Earth is the sum of all its parts. And just as the Space Age has produced deeper understanding of the interconnections and interdependence of Earth's physical and biochemical processes, so, too, has it resulted in greater international cooperation in global change research, largely through observations in space. Examples are the World Ocean Circulation Experiment I've just described, the International Satellite Clout Climatology Project and the Ocean Drilling program.