California's population growth slowed a bit last year, according to the latest official estimates, probably because of the sluggishness of the state's economy - but one should quickly note that even slower growth still meant a half-million-plus more human beings.

The term "human beings" is important because there's a strange tendency among those who discuss such things to speak of "growth" in disembodied terms of sprawling subdivisions or traffic congestion, and ignore the simple fact that those phenomena merely reflect expanding numbers of warm bodies.

The latest numbers come from the state Department of Finance's demographic statisticians, who, in the absence of a direct census, use other data to produce their remarkably accurate estimates of population growth. They calculated that California gained 532,000 people last year to top 36 million for the first time; inferentially, that means the state is on track to probably hit 40 million by the end of this decade and 50 million in the late 2020s.

Officially, the population numbers are used to divvy up various forms of state and federal aid to cities and counties and are followed avidly by local officials for their financial impact. Unofficially, however, they mean that the spurt of population expansion that first made itself evident a quarter-century ago is still very active. During the past 25 years, California's population has grown more than 50 percent, from under 24 million to the current 36 million.

The components of that growth also are well-known: immigration and a continued high birth rate. California, despite its highly publicized economic, fiscal and cultural problems, continues to be a magnet for immigrants, attracting roughly a third of those who, legally or illegally, make their way to the United States each year. And about 60 percent of the half-million babies born in California each year have immigrant mothers.

The economic and social absorption of so many millions of people from so many disparate cultures is one of California's remarkable success stories, one exemplified by the evolution of one poor immigrant into a motion picture superstar and the state's latest governor. At the same time, however, the ever-increasing numbers of Californians, regardless of their origin, have an immense impact on the private and public infrastructure that continues to befuddle political policy-makers.

To keep pace with its inexorable population growth, California needs to build 200,000 units of housing each year, find space on the roads for 1,000-plus more vehicles each day and accommodate tens of thousands of new kids in school each year. And that doesn't count such factors as water or sewage treatment capacity.

Retailers, commercial real estate firms and housing developers are pouring billions of dollars into a market they see as expanding almost limitlessly. And local governments have, in the main, responded to population pressures as best they could. But state government has been laggard, neglecting its own responsibilities such as transportation and water and sending a mixed message on housing.

Legislators often enact decrees on local governments to build more housing, but just as often impose expensive regulatory impediments to housing in response to pressure from labor unions, environmentalists and other groups, and adopt tax policies that discourage housing projects.

The Schwarzenegger administration is working on a "smart growth" initiative that, among other things, would offer local governments more financial incentives to promote housing construction as part of a larger overhaul of the division of tax revenues between the state and local agencies. But its budget also continues the virtual moratorium on vital transportation projects by dipping further into fuel taxes to offset general fund deficits.

A continued high level of population growth is inevitable in California. The question is whether we will officially acknowledge that fact and do what is necessary to mitigate its negative effects by adopting policies that will ensure the infrastructure will be in place to serve the millions more human beings who will call California home in the decades ahead. The other option is chaos.