Roy Beck: It's About the Numbers.

Last year, Roy Beck and Leon Kolankiewicz released a report entitled Sprawl in California that used U.S. Census data to challenge some of the traditional assumptions about why cities spill beyond their borders. "California's population boom has been the number one factor in the state's relentless urban sprawl, even though most anti-sprawl efforts exclusively target consumption factors," the report concludes.

Roy Beck challenges conventional wisdom as director of NumbersUSA, a population policy group and website based in Washington, D.C. He advocates reducing immigration levels to allow the U.S. population to stabilize, but he's no immigrant basher. "To talk about changing immigration numbers is to say nothing against the individual immigrants in this country," he says.

E: In California, what is the connection between population growth and environmental degradation?

Roy Beck: I think the clearest sign is the recent National Wildlife Federation study, which found that sprawl is the number one threat to species. In fact, most California cities have been reducing the amount of land consumed per person. But they have had such amazing population growth that the cities are tending to spill out over the countryside.

How much of California's population growth is due to immigration?

In the 1990s, new immigrants comprised nearly all of the population growth in the state.

What would happen to population in California if there were no immigration?

There will be immigration, and nobody is proposing that we stop it completely. But if there were no immigration at all starting right now, then population growth would be cut in half. The reduction is not higher because many immigrants already here have high fertility rates. That part of population growth would continue for some time.

How do environmentally based groups that call for a limit to immigration growth defend against charges of racism?

I believe the majority of leaders in immigration reduction policy aren't in the least bit racist. But we must recognize that there is a small segment of people who have racial reasons for wanting to limit immigration. We also have to recognize that there are people who push for high immigration for racial reasons. There is racism and racial reasoning all around, but we are not suggesting that immigration be changed based on race or national origins. It's all about reducing the numbers.

Is that principally how the modern movement differs from the nativist movements of the nineteenth century?

Absolutely. Nativist movements were predicated on a dislike of the characteristics of the immigrants who were coming in, primarily because they were of a different ethnicity. But even in the 19th century, there was a broad, progressive coalition of people and groups advocating immigration reform on a non-racial basis, without anti-immigrant feelings.

Can you describe how sprawl and other deleterious environmental problems might affect California's environment by 2025 if there are no checks on immigration? The state could have 54 million people by then.

Every environmental problem in California is going to be made worse by adding 10 or 20 million people. It makes everything harder. Particularly in Southern California, people live an extremely congested lifestyle. Already, many of the cities in California are the most densely populated in the country, and the Los Angeles area is number one. Adding these tens of millions of people will cause cities to sprawl even further, destroying natural habitat and farmland.

The groups that defend high immigration levels say factors other than sheer numbers, like bad urban planning and corporate pollution, are really behind environmental degradation.

You have to look at how those 20 million new residents will live. Will they sleep in three shifts in a single apartment, the way some people do in Hong Kong, or will they live in 3,000-square-foot houses? The standard of living, and the level of consumption of each of those individuals, has a tremendous effect on the environmental impact. But a reduction in consumption levels is a "what if," and it doesn't mean much. What really counts is what is happening right now. We know the people of California are unwilling to pass laws to force residents to drastically reduce their consumption levels. Unless that happens, the 20 million people coming in are going to consume at relatively the same levels as Californians right now. Even if you could bring about a 25 percent across-the-board reduction in the way all current Californians live, the next 20 million people would still cause a significant increase in environmental degradation. We are looking at a 55 percent increase in population over the next 25 years, and that would totally overwhelm modest lifestyle gains.

Can you say the same thing about energy use? I have heard that per capita energy use among Californians is actually decreasing because of conservation, but the savings get overwhelmed by population growth.

If you look at the energy required for California today versus 20 years ago, you find that almost all of it is the result of population increase. I hate to say something so strongly, but people who claim that the level of population growth is not a significant factor are basically people who live in a dream world. They don't think that two plus two equals four. It's anti-intellectual, and it has no place in environmentalism. CONTACT: NumbersUSA, [phone], www.numbersUSA.com.