They're just columns of numbers printed on pieces of paper. But a series of recent statistical reports constitute a time bomb waiting to explode with far-reaching and potentially disastrous social, economic and environmental consequences.

The first was a herculean compilation of data by a private organization called Children Now, demonstrating conclusively that California's children face increasing risks of poverty, medical problems, cultural deprivation, educational failing and even death.

Then came another report from the Washington-based Center for the Study of Social Policy that not only confirms the Children Now findings but reveals that in overall conditions, California's children are 33rd among the states.

Next, the state Department of Social Services issued what should be a very sobering report on teenage pregnancy in California. In 1987, the state's teenage birthrate was below the national average, but just five years later it had soared to twice the national average and the highest of any state. One in every 15 teenage California girls gave birth last year, more than half of the women now receiving welfare checks had their first children as teenagers, and 31 percent of all births in California are to unmarried women.

Finally and most devas-tatingly, the state Department of Finance issued a prediction that California's explosive population growth, largely the product of a sharply increasing birthrate, is likely to continue unabated for decades to come.

The high levels of foreign immigration - primarily from Asia and Latin America - that California began to experience in the late 1970s have produced a bumper crop of babies. Immigrants were mostly young and came from cultures that value large families. A decade ago, California women were giving birth to about 300,000 babies a year and the birthrate was not much above a replacement level. But today, more than 600,000 babies are being born each year and the overall birthrate has climbed well beyond the replacement level and is expected to continue to rise for decades to come.

The Department of Finance projects that California's popu-lation, now about 32 million, will double in the next 50 years, with babies being the chief compo-nent of that increase, supple-mented by continued high levels of foreign immigration. It is the equivalent of adding a San Francisco to California's population every year or a Massachusetts every decade.

The potential consequences of such numbers are staggering. Take, for example, the impact on schools. California must build 20 classrooms each day, 365 days a year, for as long as we can project into the future just to keep pace with school enrollment growth, plus find the money for teachers' salaries and other operational expenses. Without any adjustment for inflation, simply keeping up with the additional two million schoolchildren expected to be in the schools 10 years from now will cost taxpayers $9 billion more each year - money that cannot be spent on desperately needed improvements in educational quality that will prepare youngsters for a rapidly changing economy.

The potential impacts on housing, transportation, water supplies, waste disposal systems, parks, air quality and other environmental and infrastruc-ture elements are equally severe.

Politicians shun these long-term issues because they are complex and carry overtones of ethnic and generational conflict. But the quality of life for all Cali-fornians, rich and poor, Anglo and non-Anglo, elderly and young, is under assault. Our very existence as a society depends on our ability to defuse this demo-graphic time bomb before it explodes in our faces.