Why are these dramatic changes taking place? Because the human population is surging. (It took a million years to reach two billion people. In the last 40 years, world population has doubled. And in the next 40 years, the number of people could double again.) Because the industrial, scientific and technological revolutions magnify the environmental impact of these increases, and because we tolerate self-destructive behavior and environmental vandalism on a global scale.

Why, once again, do we fail to rally our forces? Much of the world closed its eyes as Hitler marched because the only adequate response was a horrible war many hoped to avoid. Do we now shrink from the unimaginably difficult response demanded by the global environmental crisis, and hope against hope that it will yet prove unnecessary? This crisis is so different from anything before that it is hard to believe it is real. We seize scientific uncertainties, however small, as excuses for inaction. Some, like Prime Minister Neville Chamberlain in Munich, would rather adapt to the threat than confront it. This time, they are protected not by an umbrella but by floppy hats and sunglasses.

Our complacency stems in part from a standard of living dependent on rapid consumption of the earth's resources. Our generation has inherited the idea that we have the right to appropriate for ourselves the earth's accumulated treasures as quickly as we can consume them. We reach back through millions of years for the deposits that fuel our industrial civilization.

Just as a drug addict needs increasing doses to produce the same effect, our global appetite for the earth's abundance grows each year. We transform the resources of the past into the pollution of the future, telescoping time for self-indulgence in the present.

In 1987, carbon dioxide levels in the atmosphere began to surge with record annual increases. Global temperatures are also climbing: 1987 was the second hottest year on record; 1988 was the hottest. Scientists now predect our current course will raise world temperatures five degrees Celsius in our lifetimes. The last time there was such a shift, it was five degrees colder; New York City was under one kilometer of ice. If five degrees colder over thousands of years produces an ice age, what could five degrees warmer produce in a lifetime? In a classic experiment, a frog dropped in boiling water jumps out. The same frog, put in the water before it is slowly boiled, remains in the pot. Our environment is at the boiling point. Will we react?

The 1990's are the decade of decision. Profound changes are required. We must create a new global compact for sustainable development -for example, trading debts for shared environmental stewardship. Our agenda must include the following:

* A worldwide ban in five years on chlorofluorocarbons, which simultaneously destroy the protective ozone layer and cause up to 20 percent of global warming.

* Rapid reductions in carbon dioxide emissions, through increased vehicle mileage standards, increased energy efficiency and development of alternative energy sources.