Spaceship Earth: Mission to a small planet

TO hardened Washington observers, it seems a minor miracle when three turf-conscious federal agencies unite behind an effort that makes significant claims on their budgets. But the ``Mission to Planet Earth,'' as NASA calls their common cause, transcends parochial concerns. Indeed, the cause that unites NASA with the National Science Foundation (NSF) and the National Oceanic and Atmospheric Administration (NOAA) in the United States also inspires nations around the world. They feel impelled to join a common effort to understand our planet and what human activity is doing to it.

It is an immense challenge.

The aim, says geophysicist John A. Eddy of the National Center for Atmospheric Research (NCAR), is to build a data base so that, 20 years from now, we can detect significant global change. He explains: ``When somebody looks back and tries to answer questions about how is [Earth] responding to the increased CO2 or is the ozone really being depleted, ... these baselines of measurements will be in place. So I think out of it will come a new monitoring of the Earth, a new taking the pulse of the Earth.''

This can't be done, Dr. Eddy says, unless the world's scientists, and the nations which support them, breach traditional barriers and cooperate in ways they never have before.

A National Academy of Sciences report explains that it requires ``a global view and a new effort to study the Earth and its living inhabitants as a tightly connected system of interacting parts.... An effort so defined has no real precedent, for it would require not only the cooperation of nations but an intercourse and sharing between fields of study that are often isolated and territorial.''

THE International Council of Scientific Unions (ICSU) - the premier world science organization - is organizing this effort as the International Geosphere/Biosphere Program (IGPB).

Eddy, who chairs the IGBP committee in the US, notes that in the past ICSU scientists have stuck to their specialties. Meteorologists studied the atmosphere. Biologists dealt with life forms. Oceanographers looked to the sea. Now specialists must learn each other's disciplines well enough, and work together closely enough, to find the underlying unity. In the past, nations supporting ICSU programs contributed specific projects for relatively limited periods. Now they're being asked to commit themselves to a world effort that will probably continue into the next century. That means shaping national research programs in ways that make a contribution to this common purpose.

IGBP proponents don't think that it will be easy to transcend the old limitations. Yet, when the project was presented to ICSU members last September, Eddy says, ``It was almost like pushing on a door that you think is stuck and it just swings right open. ... ``All I can say is that the spirit right now is so strong for it, I think there'll be ways of getting around the [barriers]. Also, there's the feeling that you just have to do it for the Earth.''

Monitoring the health of Planet Earth requires extensive study of the oceans. That includes research within territorial waters and within the exclusive economic zones that extend 200 miles beyond national shores, as well as on the open seas. It involves extensive surveys and data-gathering on land. And, what is most important, it requires an international network of Earth-observing satellites whose data are freely shared among all nations.

The impetus to share internationally also helps meet national needs to build strong earth-science programs. In the US, this motivation has forged the NASA-NOAA-NSF alliance. NOAA administrator Anthony J. Calio has pointed out that, because of the pressure on agency budgets due to the federal deficit, ``there's a natural climate for us to coexist these days.'' He added, ``This forces us to work closer and closer together.''

The three agencies are cooperating to carry out the strategy outlined last year in the report of the Earth System Sciences Committee (ESSC) of the NASA Advisory Council. This, essentially, will be the US contribution to the IGBP. It would start by coordinating existing and planned research programs as part of a master research plan now increasingly called ``Mission to Planet Earth.''

THIS will require some extra funding. ESSC chairman Francis P. Bretherton of NCAR has estimated that the three agencies now spend about $1 billion a year on research relevant to this ``mission.'' He foresees the need to raise that by 20 to 50 percent over the next decade. As a major effort of the three agencies, NCAR's Eddy says there's so much momentum behind the ``mission'' that ``we could probably not turn it off now if we wanted to.''

Sharing also serves the self-interest of other countries in the IGBP. Global change affects all nations. None of them can understand, or prepare for, this change on their own. Eddy says this realization has encouraged an ecumenical spirit. Beyond that, many countries find the IGBP a fruitful way to join in advanced scientific activities.

Eddy notes that the Chinese, for example, are very interested. He suspects ``they look upon it as another way of bringing China scientifically right into the big league of international power in science.'' Many Chinese, he adds, also ``are very concerned about the environmental impacts being wreaked on that country in the last few years. They're alarmed about it. And this seems like a positive step for them.''

One of the main keys to understanding what's happening to Earth is efficiently handling the massive information flow IGBP research will generate. Data need to be available quickly and in meaningful form. Eddy points out that, not only is this probably the biggest technical challenge facing the program, ``It also offers something to all third-world countries.'' It's an aspect of advanced scientific activity in which they can participate with relatively little expense.

``This sort of common data source ... enables countries to really come up to speed in science real fast,'' Eddy says, adding, ``It will also break down a lot of barriers.''

Satellites: keen vantage points for Earth study

ONLY a couple of decades ago, the notion of keeping tabs on Earth as a whole would have amounted to hubris.

In those days, Robert M. White - now president of the National Academy of Engineering - was helping to organize international earth-science programs.

Dr. White notes that you can't cover the sea with ships, sow the land with sensors, or fill the air with instrumented balloons. In fact, he says, ``The whole concept of setting up an observational system for global change is just uneconomical and not at all, in principle, possible without a [space] platform from which you can observe the globe.''

That platform is the satellite. And thanks to sensors available, or soon to be available, for that platform, ``We have a technology now which enables us to think about studying the global environment over long periods of time which we never had before,'' White says.

Besides their views of swirling cloudscapes, weather satellites can also sense winds and the vertical distribution of temperature throughout the atmosphere.

Today, winds observations are derived from cloud motions, and are rather crude. However, studies at the NASA Goddard Space Flight Center have suggested that satellite lidar (laser radar) could trace wind patterns by tracking dust and other pollution.

Computer programs derive temperatures from data on infrared (heat) radiation which satellites detect coming from the atmosphere. Tracing winds and waves

In this way, the distribution of temperature with height is obtained over virtually all of the planet with a vertical resolution of three to four miles.

So-called passive sensors of naturally-emitted microwave radiation and satellite radar have opened new ways of viewing the planet, especially the oceans. Sensors can trace winds, waves, and currents. They can even map the bottom of the sea.

The TOPEX/Poseidon satellite - a joint French-United States project - will carry a radar altimeter that will measure sea-surface height to within one-inch accuracy. To be launched in late 1991 on a European Ariane rocket, this precision radar should enable scientists to trace large-scale circulations, whose flows are reflected in sea-surface slope. Differences in gravity effects due to underwater topography should also show in the sea-surface maps. Careful measurements of the orbital motion of specially designed geodetic satellites already allow the shape of Earth's gravitational field to be measured.

Another type of satellite radar allows computer programs to estimate surface wind speed and direction by analyzing the scattering of radar signals by waves. And, according to a study by Thomas T. Wilheit of Goddard Space Flight Center, analysts may be able to estimate precipitation by the way naturally emitted microwave energy is attenuated and scattered as it moves through the atmosphere into space.

Remote-sensing satellites such as the American EOSAT (Landsat) and French SPOT add yet other insights. Their data allow extensive geological analysis; monitoring of farms, forests, and deserts; and reveal the growth and decline of algae and other microscopic plants and animals which are the base of food chains in the sea.

Satellites can even help study the historical interaction of people and their environment, as the NASA Ames Research Laboratory reported recently. Perspective on history

Using Landsat images and data gathered in 1978 by the Seasat radar-carrying satellite, Ames researchers have traced an ancient river plain, sea-level changes, and fault lines in Central America. They can relate these to old Mayan settlements and to their natural wells and ponds. This is giving new insight into how the Mayans adapted to their local resources.

Thus the technology which now enables us to keep track of what we're doing to Earth may also help us understand what ancient people did to their environment as well.

Part two of a three-part series. Tomorrow: Managing the planet.

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