The New York Times

April 17, 1981

By David M. Burns

WASHINGTON - The atmosphere's carbon-dioxide content has increased 7 percent since 1958, when systematic measurement began. Scientists fear that the continued use of fossil fuel and continued landclearing and destruction of forests will raise the quantity of CO2 to double the pre-industrial level. We fear that if the theoreticians of climate are correct, sometime in the next 100 years there will be a virtually irreversible shift in the Earth's climatic pattern; it would be on a scale unprecedented in human history. Such a ''greenhouse effect'' could lead to great disruption; there might be benefits, but also costs, such as widespread hunger.

Life on this planet is possible because we have water and a blanket of life-supporting gases. Earth is solar-powered, and the heat balance is critical. We know something about the geophysical and biological systems on which we depend, but it is humbling to realize how little we know for sure.

Some cycles appear to be fragile, with the natural equilibrium easily disturbed. Others seem to be robust and are not easily perturbed by minor change. The webs are complex, and we are only now beginning to quantify some of the relationships. We do not know what will happen to our life-support system if we alter a fundamental component such as climate. We are engaged in an uncontrolled experiment.

The issue of carbon dioxide and its relationship to climate change is global in its implications. But since some regions might benefit from change while others lost, international agreement is unlikely. Unilateral action by any country would be ineffective. Moreover, the issue has ethical implications, might lead to international political conflict, and seems unlikely to go away.

Climatologists say that it may be several decades before we can detect, through the statistical ''noise'' of normal fluctuations, carbon dioxide-induced climate changes. Such changes are likely to be incremental and barely perceptible from year to year. Energy experts remind us that historically it has required 50 years to switch from one energy source to another. The future is unknowable: Wars or random and unimaginable events may upset carefully plotted predictions. Given scientific uncertainties, long lags required for proof or prevention, and public-policy overload, carbon dioxide induced climate change may be an issue that politicians choose to ignore.

The population of Earth is likely to double in 50 years, and there will be growing demands for food, water, fuel, and natural resources. Climate change would be an added burden on severely strained social and economic systems. If the change brought a permanent drought, for example, to regions near the limit of their agricultural productivity, famine or migration could result.

There is no global policy of mutually assured survival. Natural disasters have the severest impact on poor people in poor countries. Highly developed countries are affected mainly in economic ways. Their complex infrastructures are brittle but their institutional and human resources enable them to cope. Rich countries also have the greatest potential to exploit any favorable change in climate or possible benefits such as the use of carbon dioxide as a free fertilizer.

Even if there were no critical gaps in the data, implementing a global carbon-dioxide policy would still be difficult. The current uncertainties are not likely to be quickly resolved, but uncertainty does not relieve us of the burden of decision. Are there reasonable and prudent actions that buy time or protection? I think there are.

The issue cannot be safely ignored in setting energy and natural resource policies, but it probably will be. We do not know enough to say what what amount of increase of carbon dioxide is safe, and would be unsuccessful if we tried to enforce any such global limit. By the time we were certain that a carbon dioxide-induced climate change was occurring, it would be too late to prevent it.

But it is possible to slow the rate of CO2 buildup. Energy conservation and renewable and nonfossil sources - for example, biomass and solar power -make sense for economic and national-security reasons, even if a climate change does not occur.

It is possible to improve the odds for the poorest countries. Slowing the rate of population growth, increasing food production, improving water supplies, establishing firewood plantations for fuel - these steps are urgently needed, even if a climate change does not occur.

It is possible to improve our understanding of the connections between physical, biological, and social systems, all of which contribute to the carbon cycle and all of which would be affected by climate change. This will require time, commitment by the world's scholarly community, and sustained funding. We need such understanding - even if a climate change does not occur.
David Burns directs the climate project of the American Association for the Advancement of Science.

GRAPHIC: Illustrations: Cartoon