PERSPECTIVES ON IMMIGRATION : The Issue Is Overpopulation : At present growth rates, including fertility, the U.S. population will double in the next century.

Given recent budgetary problems, it may be difficult to convince Californians that the drain on public services is not the principal issue in determining how much immigration we can afford. In the long run, the impact on population growth will be the most lasting legacy of our current immigration policies.

Largely as a result of immigration, the United States now has the fastest-growing population in the developed world, while immigration-driven population growth in California rivals that of some Third World countries. Population growth comes at great cost that cannot always be measured in dollars and cents.

First, we must realize that the human race is a part of the natural ecosystem of the Earth, not a privileged super-species that can transcend the laws of nature. The United States, because of its size and consumption habits, is the most destabilizing entity within Earth’s fragile ecosystem. Population growth here has a far more profound impact on that ecosystem than growth elsewhere.

The disturbances caused by human activities have accelerated dramatically in the past half a century. Driven by population growth and the technological explosion, these disturbances threaten not only the perpetuation of a way of life we have come to take for granted, but even the continuation of life systems as we understand them.

The good news is that the means for controlling and reversing these terrible forces are within our power. What we require, as a society, is the wisdom and understanding to employ them.

The United States grew from a nation of 76 million in 1900 to 249 million in 1990 (and to an estimated 260 million in 1994). Forty-three percent of that growth consisted of post-1900 immigrants and their descendants. Present immigration and fertility patterns place us on the path to a population of 397 million by 2050 and 492 million in 2100. More than 90% of that growth will be a direct result of post-2000 immigration.

In other words, our immigration policies place us in a league with the ruinous population growth patterns of countries like India and Bangladesh. Moreover, our growth is far more destructive because of our style of living. Continued high levels of consumption combined with Third World-like population growth is a prescription for disaster.

We find the idea of another doubling of U.S. population thoroughly frightening. Consider the impact on many of the nation’s current problems: urban decay and unemployment; energy dependence, nuclear waste and sewage disposal; loss of biodiversity and resistance of agricultural pests and diseases to pesticides and medicines; acid rain, climate change, depletion of water resources, topsoil erosion, loss of agricultural lands and destruction of forests, wetlands and fisheries, to name just some.

Nevertheless, there is the possibility of light at the end of the tunnel. We could bring population growth to a halt in the next century and even turn it around. First, fertility would have to fall gradually from current levels of 2 children per woman to an average of 1.5. But even that would not be enough to achieve population stabilization in the United States. Without substantial reductions in immigration, to perhaps 200,000 annually, our population still would reach 337 million by 2050.

A return of immigration to the levels that prevailed through the middle of this century will not happen by itself. We must persuade our national leaders that, while the problems of Haitian boat people and other would-be immigrants are heart-rending and real, they cannot be solved by sacrificing our own future. The United States has an obligation to its own people and descendants, one that cannot be served by allowing the population to swell to half a billion.

A commitment to our own future does not mean ignoring the problems of the rest of the world. Many developing countries are caught in a population explosion, and the United States should make family-planning assistance the first priority in foreign aid. No amount of aid will have much significance unless population growth is curbed as well.

Our primary obligation is to our own future and our primary responsibility is to control our own consumption and population growth. Our national policy goal should be to avoid adding to the annual load of pollution and environmental damage, and then to reduce it. That can happen only if we lower our fertility rate and our immigration level.