FOR environmental planners, the watchwords for the 1990s are think globally, act locally. Major environmental challenges - stratospheric ozone depletion, climate change, a possible decline in the ability of the atmosphere to clean itself - are global in scope. Yet the human activity that causes them is regional and local. It must be dealt with at national levels.
Hitting this theme in a scientific review paper in the American Chemical Society journal Environmental Science & Technology, Victor Phillips of the Hawaii National Energy Institute explains that the solutions to these challenges "will have many facets depending on local ecosystems, culture, and political economy, but will have in common a fundamental change in how we humans perceive nature."
The report on climatic warming released earlier this month by the Committee on Science, Engineering, and Public Policy of the National Academies of Science and Engineering and Institute of Medicine in Washington makes the same point. It concludes that "even given the considerable uncertainties in our knowledge ... greenhouse warming poses a potential threat sufficient to merit prompt responses." Yet, it adds that the study "does not attempt to view greenhouse warming from the perspective of a country le ss well-endowed" than the US.
For example, the world recognizes that carbon dioxide released by burning fossil fuels is one of the main heat-trapping gases driving the climate system toward global warming.
Yet, as Toufig Siddiqi of the East-West Center in Honolulu points out, a global agreement to reduce the release of greenhouse gases would have to allow for increased carbon dioxide emissions from developing nations for at least two decades. He bases his conclusions on a study by the Intergovernmental Panel on Climate Change. He explains that "developing countries that rely mainly on domestic sources of energy, usually coal, are not in a financial position to switch to cleaner imported fuels."
This theme of global thinking with local action is a recognition that the world faces common and unprecedented environmental challenges even though nations must respond in individually appropriate ways. For environmental scientists, the effort to build a solid scientific base for that common understanding is a major task of this decade.
The academy greenhouse warming report reflects the consensus of climate scientists when it notes that the computer models (programs) that predict climate change have serious flaws. They can't take adequate account of the oceans, for example.
In March, Jane Robinson and colleagues at the Plymouth Marine Laboratory in England reported in Nature, that oceanographers don't even understand how oceans absorb carbon dioxide as well as they thought they did. She called it "premature" to use computer models to simulate what happens to atmospheric carbon dioxide.
The Earth Observing System - an international program of Canada, the European Space Agency, Japan, and the United States - will help fill knowledge gaps.
This "mission to planet Earth" as the National Aeronautics and Space Administration (NASA) calls its share of the program, will monitor our environment from space. NASA plans to have a large Earth-scanning platform on orbit around 1998. Although managed by Goddard Space Flight Center in Greenbelt, Md., the Jet Propulsion Laboratory (JPL) in Pasadena, Calif., will supply major instruments.
JPL director Edward Stone calls this "a very important" research area for the laboratory that has won fame with its missions to other planets. He points out that water vapor is the most important heat-trapping gas in the atmosphere. Yet it is one on which there is relatively little data to feed into computer climate simulations. "It's difficult to know what the hydrological cycle is over the Earth as a whole when most of the atmosphere is over the oceans," Dr. Stone says.
A JPL-supplied spectrometer on the orbiting platform that will measure infrared radiation at various wavelengths will trace water vapor through the atmosphere. Another instrument that detects how waves scatter radar energy will track surface winds over the sea. From these wind data, Stone says, analysts can derive evaporation over the world ocean.
The lower atmosphere also needs comprehensive scrutiny. Reviewing this need in Environmental Science & Engineering, Jack Fishman of the NASA Langley Research Center in Hampton, Va., explains that "the self-cleansing ability of the atmosphere could be dramatically altered if the composition of the [lower atmosphere] changes significantly."
This "self-cleansing ability" is represented by what chemists call the hydroxyl radical. It is an electrically charged combination of an oxygen atom and a hydrogen atom. This highly reactive naturally occurring chemical cleans out many pollutants. However, some atmospheric chemists have suggested that hydroxyl depletion may be on the rise, although the evidence is not clear.
Last December, for example, James Kao and Xuexi Tie at the Los Alamos National Laboratory in New Mexico reported a study that suggests the Northern Hemisphere has only about 25 percent as much hydroxyl as does the Southern Hemisphere. They said the heavier industrial pollution in the Northern Hemisphere might be responsible.
However, a similar study by Clarisa Spivakovsky of Harvard University reported in the Journal of Geophysical Research last October did not find severe hydroxyl loss in the Northern Hemisphere.
But gaining more physical data alone won't build a solid knowledge base. Scientists also need to know much more about how living organisms affect the global environment. Gaining that knowledge is the job of the International Geosphere-Biosphere Program (IGBP) of the International Council of Scientific Unions.
Already five years in planning, the program is ready for takeoff. Reviewing that planning in Environmental Science & Technology, Thomas Rosswell, executive director of the program's secretariat, says,"Within the decade of the 1990s, the IGBP will launch a worldwide research effort, unprecedented in its comprehensive interdisciplinary scope."
The global scrutiny now gathering momentum will involve many programs on land and at sea. However, looking at the overall challenge, JPL's Mr. Stone, who has helped explore most of the solar system, sees a special role for spacecraft. "There's a very nice linkage in terms of technology and basic scientific disciplines in looking at the Earth as a planet," he says.