Everybody knows that California's population is growing like the proverbial weed. The state's population expanded by 6 million in the 1980s to 30 million, and, left unchecked, it will add another 7 million to 8 million in the 1990s.

Everybody--well, not everybody, but the vast majority of Californians--also believes that we should find some way of dealing with that growth, rather than just let it happen, the way it did in the last decade.

But what? That's the question whose answer, or answers, may be too politically painful to endure.

Governor Wilson has created a Council on Growth Management to be chaired by his office of Planning and Research director, Richard Sybert. Among other things it signals that Wilson, unlike predecessor George Deukmajian, doesn't want to ignore population growth as a political issue. But it also implies a certain limit on the Wilson adminis-tration's response to the phenomenon that drives almost everything else, from economic prosperity to the crisis of public education to overcrowding of state prisons.

Wilson's charge to the Council on Growth Management is to find ways of coping with the effects of growth, rather than attacking the problem at its source. Implicitly, population growth is seen as something akin to the weather an important political, economic and social factor, but one that cannot be materially altered. Indeed, one point in the Wilson growth management program--the maximizing of job creation--may actually encourage greater in-migration.

Wilson is not alone in not wanting to open a full debate on population growth and its causes.

The Sierra Club issued a white paper Wednesday entitled Policy Before Planning Solving California's Growth Problems. It cataloged the collateral impacts of population growth, such as rising levels of air and water pollution, the disappearance of green belts, the driving of land-use decisions by local governments' fiscal problems and the ever-increasing use of private automobiles for transportation.

It proposes a number of state and local policy changes that would, it said, mitigate adverse impacts of high growth levels. But when it came to the root causes of population growth, the Sierra Club became very cautious.

It agreed that the state's relative prosperity makes it attractive to immigrants and high birthrates contribute mightily to population expansion, it warns that even California's current population size is putting pressures on the environment that are not supportable in the long run, it worries that the state's population may be growing even faster than current demographic projections and it endorses, conceptually, having a stable population rather than a fast-growing one. But it chokes when it comes to advocating poli- cies that might slow or reverse the trend, other than adequate funding for family-planning programs so unwanted fertility in the state is reduced to an absolute minimum. It talks about population goals, but provides few clues on what they should be or how they should be achieved.

The unvarnished facts are that California's population is growing rapidly because of wide-open international borders, because the state's economy offers opportunities unmatched by those in adjacent societies, whether they be in other states or nations, and because recent immigrants tend to have relatively high birth rates.

Dealing with the causes of California's pheno- menal population growth would require a crackdown on legal and illegal immigration, a conscious decision to limit economic growth and job creation and some really tough, perhaps even coercive, birth control policies. Any one of those steps would create a political firestorm with overtones of inter-ethnic and inter-class conflict. That's why Sierra Club consultant Judith Kunofsky describes population limits as virtually undiscussable.

It's unlikely--bordering on impossible--that California could muster the political will to adopt those policies and it's possible that achieving zero population growth would create its own set of serious social and economic problems.

Thus, mitigation may be our only achievable response. If so, we should be willing to admit it rather than dancing around the central point.