Let us be thankful that earth's atmosphere is a thin blanket of gases wonderfully designed to keep us warm. Like a greenhouse, certain gases trap the sun's energy and maintain a climate that sustains life. Without these greenhouse gases, the average temperature on earth would be 60 degrees Fahrenheit colder, and life would be impossible. We can also be thankful that ancient conditions led to the formation of coal, oil, and gas-the fossil fuels. We have built a gigantic global economy based largely on the energy extracted from burning fossil fuels. Although the oil and gas may run out fairly soon, there is enough remaining coal to sustain our economy far into the future. We have a problem, though. It is a matter of fact that burning fossil fuels adds carbon dioxide-a major greenhouse gas-to the atmosphere. And if we were to burn all the known reserves of coal, oil, and gas, the concentration of carbon dioxide would rise to about eight times the present level-from 360 parts per million to 2,700. The climate would undergo enormous changes under those conditions, especially changes in temperature. Already, the concentration of carbon dioxide is 30 percent higher than it was before the industrial revolution, and it is rising every year. If this doesn't concern us now, it will certainly concern our grandchildren and their grandchildren. This leads to a dilemma: Shall we take action now to restrain our use of fossil fuels to benefit future generations, especially when we think there will be severe economic consequences-to us-of this exercise of restraint? This is the dilemma facing the delegates from 166 countries as they meet in Kyoto, Japan, in December to consider action to cut back on greenhouse gas emissions, primarily by burning less fossil fuels. In 1992, the Framework Convention on Climate Change was debated and signed; the goal all agreed upon was "stabilization of greenhouse gas concentrations in the atmosphere," but no binding action was taken. The context of this dilemma is global climate change. Global warming is only one of the potential consequences of the increase in greenhouse gases; the global climate connects oceans, atmosphere, and land in a complex, poorly understood system. If we continue with business as usual, it is inevitable that the sea level will rise; droughts, floods, and storms will intensify; and the changes will be more rapid than the ability of biological systems to respond. This is not something I want to wish on my grandchildren. How sure can we be that the climate will indeed change? If greenhouse gases continue to increase indefinitely, we can be absolutely certain. Is there evidence that it is already changing? Perhaps it is just coincidence that the sea level is rising, global temperatures are rising, Alaska is warming up, polar ice sheets and glaciers are receding, storm events are more frequent and severe-as the amount of greenhouse gases has continued to rise. In the scientific community, there is a clear consensus that this is a serious problem-in fact, the most serious problem facing our global community. The longer we wait to move toward stabilization, the harder it will be to achieve it, and the higher the level of greenhouse gases when stabilization is actually reached. The real opposition to effective action is rooted in short-term self-interest-economic and political. Meanwhile, in Kyoto the nations will-sadly-be debating whether to cut back fossil fuel use 5 percent, or 10 percent, when it would take a 50 percent cut to bring about stabilization. I fear that global economic interests will prevail, and that our grandchildren will suffer the consequences. Mr. Wright is Professor of Biology at Gordon College in Wenham, Mass. He is co-author of Environmental Science: The Way the World Works (6th ed.), published by Prentice Hall, and a member of the Christian Environmental Council.