ENVIRONMENTALISTS have welcomed the agreement in principle to restrict chemicals that may harm Earth's ozone layer. They see it as a small step toward tackling massive environmental problems that have planetary scale. But the accord reached at the United Nations Environment Program conference in Geneva at the end of April is a very small step indeed when considered in the context of this environmental challenge. The report of the UN World Commission on Environment and Development - coincidentally released while the ozone conference was in session - describes that context. To use the commission's term, it describes a ``new reality'' of life on Earth that humanity has scarcely begun to face.
The report says: ``From space, we see a small and fragile ball dominated not by human activity and edifice but by a pattern of clouds, oceans, greenery, and soils. Humanity's inability to fit its doings into that pattern is changing planetary systems, fundamentally. Many such changes are accompanied by life-threatening hazards. This new reality, from which there is no escape, must be recognized - and managed.''
Learning to exercise such management will be difficult and complex. As the commission notes, ``ecology and economy are becoming ever more interwoven ... into a seamless net of causes and effects.'' Also, as the report observes, ``the industries most heavily reliant on environmental resources and most polluting are growing most rapidly in the developing world, where there is both more urgency for growth and less capacity to minimize damaging side effects.''
The threat to the ozone layer is only one small aspect of that assault. Sunlight creates ozone - a form of oxygen with three atoms per molecule - high in the stratosphere. This ozone then absorbs harmful solar ultraviolet radiation. Chemicals of a class called chlorofluorocarbons (CFCs), which are used as refrigerants and sometimes as spray-can propellants, escape into the atmosphere. When they work their way into the stratosphere, they take part in complex chemical reactions that, among other things, destroy ozone.
Details of what nations will do to limit CFC use have yet to be worked out. But it's already clear that the burden of sacrifice probably falls most heavily on the developing world. Just when many developing countries want to expand their use of refrigeration, they are being asked to curtail their expectations.
This asymmetry of sacrifice will loom even larger as nations face up to the so-called ``greenhouse'' climate-warming effect. Carbon dioxide (CO2) from burning fossil fuels and some other gases, including CFCs, that are accumulating in the atmosphere trap outgoing heat radiation and warm the planet. As detailed during a symposium at an American Chemical Society meeting last month in Denver, the rising concentration of methane in the atmosphere can have as large a warming influence as CO2. While the cause of methane's increase is not fully known, it's linked to population growth and economic development, especially to intensified global agriculture.
As with the threat to the ozone layer, pressure is building to ``do something'' about the greenhouse problem. But any substantial global effort to restrict use of fossil fuels and other activities that release greenhouse gases would ask poorer nations to restrict their economic development. This is why greenhouse effect researcher Stephen H. Schneider of the National Center for Atmospheric Research in Boulder, Colorado says that, while significant, the threat to the ozone layer is far from being the world's most important environmental problem.
He explains: ``The world's most important problem ... is how are we going to get decent economic conditions, living conditions for a billion people without committing the future to an unsustainable environmental or economic regime. This is not an easy job. And it may involve substantial amounts of increased development, which means more pollution. I'm willing to live with that, personally, if it's connected to plans to reduce population growth rates and stabilize in a sustainable way. This involves sort of planetary scale bargaining.''
If the ozone accord is a start toward such bargaining, we can indeed welcome it. But if protecting the ozone layer is considered in isolation as an end in itself, it will be a futile exercise. Whatever good may be done will be lost in a larger environmental collapse. As the UN commission urges, it's time humanity faced up squarely to Earth's ``new reality.''
A Tuesday column. Robert C. Cowen is the Monitor's natural science editor.