By Donella Meadows
–February 16, 1989–
Over the next decade the world will critically need an eye on itself. We will need to keep track of greenhouse warming, forest damage from acid rain, the extent of deserts and tropical deforestation. We can deal with global environmental problems only if we have accurate information about whether and where those problems exist.
The good news is that we have that information. The Landsat program has been sending us satellite images of the earth’s surface since 1972. Landsats 4 and 5, in orbit now, provide a complete global picture every two weeks. The wavelengths they scan are uniquely suited for detecting changes in vegetation. Thanks to them we have a historical record of the global environment and a sensitive early warning system to spot trouble. The bad news is that the National Oceanic and Atmospheric Administration (NOAA) is planning to stop collecting Landsat data after March 1 of this year, and will abandon the satellites on April 1. The reasons for this move begin with the Reagan administration’s program to privatize government functions and end with an unwillingness to come up with 26 million dollars (out of a total government budget of over one million million dollars).
The Reagan idea was that Landsat could pay for itself by selling its earth images to commercial clients such as oil companies, which use them for exploration. Responsibility for Landsat was transferred from NASA to NOAA (in the Department of Commerce), which created EOSAT, a private corporation managed by a coalition of aerospace firms. EOSAT’s job was to market Landsat images.
Oil companies, it turns out, only need one good earth scan every eon or so. The primary users of Landsat — scientists studying environmental changes, Third World countries doing basic resource inventories — were priced out of the market when EOSAT quadrupled the charge for an image. EOSAT management squandered money, marketed poorly, and became a continuous drain on NOAA’s budget. Finally Congress, disgusted with EOSAT’s inefficiency and in high cutting mood, decided to pull Landsat’s plug.
If after March 1 the stream of data coming from Landsat is no longer received, a 17-year series of planetary information will be interrupted. If after April 1 the satellites are no longer maintained, the solar collectors will not stay pointed toward the sun or the sensors toward the earth. The satellites will start tumbling. Further communication with them will be impossible.
We have other earth-scanning satellites in the sky, and so do other nations. The French and the Russians have them and the Japanese are about to put one up. But only Landsat reads the earth through a set of high-resolution near-infrared and short-wave spectral bands especially suited to provide information about stresses in vegetation.
Professor Barry Rock and his research team at the University of New Hampshire use Landsat to watch the effects of acid rain and air pollution on the New England forest. They correlate the wide sweep of satellite information with more thorough but scattered ground studies. Every now and then the researchers find the satellite images not only predictably useful, but unexpectedly so.
Rock has found “acid rain false alarms”, unusual spots of forest dieback that turned out upon ground inspection to be not acid rain damage but toxic dump sites. Through the satellite images he can not only find the dumps but monitor whether the vegetation returns after they are closed. Late last June the Northeast suddenly realized it had a problem with a hitherto uninteresting insect called the pear thrip. It was rampaging through the sugar maple forests, defoliating as it went. By the time authorities began to ask insistent questions, the insect’s feeding cycle was over, the trees were putting out a late crop of leaves, and the infestation was hard to map. But Rock could call up Landsat images from June 5, when the trees were maximally defoliated, and another set of images from a previous, uninfested June. He could chart the insect’s spread with great accuracy, which provided a basis for predicting its possible future advance.
These stories show three essential features of Landsat — 1. its fine resolution (to 30 meters), 2. its use of wavelengths particularly sensitive to vegetation under stress, and 3. the continuity of its record. No one knew in advance that we would want to trace a New England pear thrip outbreak, the ecological damage from Chernobyl, the burning of the forest in Amazonia, the drought in the Midwest, or the effects of the ozone hole on the plants of Argentina — but when we did need to know those things, Landsat data were there waiting for us.
Landsats 4 and 5 have both already exceeded their design lifetimes. Satellites have a good record of doing that, however, and there is hope that these might last until Landsat 6 is launched (now scheduled for 1992) — if the nation recovers its senses and decides to keep them alive. There are many ways to do that. Cancel EOSAT and give NOAA a proper budget for maintaining Landsat. Or give the responsibility back to NASA. Charge Secretary of State Baker to enter international negotiations on the greenhouse warming and seek a worldwide shared commitment to continuous satellite monitoring with data available to all.
It makes no economic sense to shut down Landsat. It would be a scientific tragedy to do so. At this time of great environmental uncertainty, it could be an ecological tragedy too.
Copyright Sustainability Institute 1989