Look at the top-priority campaigns of the nation’s big environmental groups and you’ll find endangered animals, pollution and global warming.

What’s largely missing are high-profile, domestic initiatives that tackle what many conservationists agree is a chief source of these and other challenges: U.S. population growth.

The environmental establishment has mostly abandoned talking about the nation’s growing populace, particularly as it relates to immigration. The topic is dogged by internal squabbles, divisive politics and a desire to avoid ethnic discrimination.

One result is that ecological factors are rarely mentioned in the current effort to establish a new immigration policy. The debate mostly centers on economics and national security.

“People have been avoiding it like the plague,” said U.S. Rep. Brian Bilbray (R-Carlsbad) a hawk on illegal-immigration issues.

“(Environmentalists) will sidestep major challenges to what their stated goal is because it may end up stepping on political friends’ toes,” he said. “They have credibility problems when they are willing to look the other way.”

Leaders of big-name green groups said they focus their energies on a larger issue: global population growth.

“Some people...want the Sierra Club to have a position that is more U.S.-centric,” said Stephen Mills, the club’s international program director in Washington, D.C. “We feel that the entire planet is worth protecting, not the U.S. over anywhere else.”

The United States is the world’s third-most populous country, after China (1.3 billion people) and India (1.1 billion). The nation’s population has nearly doubled since 1950, and the count is expected to hit 300 million in October, according to the U.S. Census Bureau. By 2050, the figure is projected to top 419 million.

Gaining Attention

As the U.S. population increases, the link between population and the country’s environmental capacity—its water supply, farmland, fisheries and other natural resources—is getting more attention from groups that aren’t among the marquee names in environmentalism.

“It’s an issue whose time has come,” said Vicky Markham, director of the Center for Environment and Population, a nonprofit research group in New Canaan, Conn. “The scientific data pretty much across the board shows that we in the U.S. are reaching many of the nation’s ecological limits, one by one, and that many (limits) are linked to population trends.”

Markham  said the center, founded in 1999, is nonpartisan and funded by grant-givers such as the MacArthur and Hewlett foundations.

The group works with universities such as Duke and Yale to assess the effects of population growth on the environment. It sometimes teams with large, mainstream environmental organizations, including the National Wildlife Federation. Markham  said the environmentalists mainly have provided scientific information about ecological trends.

Such alliances are one low-key way for conservation groups to dabble in domestic population issues. Other tactics include backing sex-education programs aimed at curbing teen pregnancies and printing articles in club magazines about, among other things, the human population’s impact on wildlife.

“It’s a shame that (environmentalists) haven’t found a way to get involved” in a prominent way, said Paul Steinberg, director of the Center for Environmental Studies at Harvey Mudd College in Claremont .

Concerns Over Growth

Most academic efforts to study the environmental impact of population growth focus on the global scale. More than 98 percent of the world’s population growth is occurring in developing countries, Markham  said. There are more than 6.5 billion people worldwide.

In contrast, Markham ’s center has zeroed in on the United States  as the only industrialized nation whose population is growing significantly.

Countries in Europe , along with Russia  and Japan , have shrinking populations because births aren’t keeping pace with deaths. The governments of several of those nations are trying to reverse the pattern with public outreach campaigns and financial incentives for couples to reproduce.

“America’s relatively high population growth and high rates of resource consumption and pollution make for a volatile mixture resulting in the largest environmental impact per capita ... in the world,” read a report by Markham’s center that’s scheduled for release in September. The San Diego Union-Tribune previewed the document.

The study, which gathered existing research from hundreds of sources to highlight population-related trends, makes no policy recommendations.
 
Among its findings:

• Americans occupy about 20 percent more developed land per capita for housing, schools, shopping, roads, and other uses than they did 20 years ago. That’s partly because the average number of people per household has dropped while the average size of homes has swelled. The increasing sprawl tends to boost vehicle use and petroleum consumption.

• About 40 percent of the nation’s rivers and 46 percent of its lakes are too polluted for fishing and swimming. Wetlands, the biological filters for water pollution, are shrinking by 100,000 acres a year, mainly because of development.

• Roughly 6,700 species in the country are at risk of extinction, most often because of habitat loss.

• Half of the continental United States no longer supports native vegetation, largely because people have altered the terrain significantly.

More than half the U.S. population lives within 50 miles of the coast, Markham ’s report stated. That density can damage seaside ecosystems such as wetlands, the report said, and continuing coastal development is expected to increase the pressure.

Such challenges are evident in places like San Diego County , home to some 3 million people and 42 threatened and endangered species. For example, having an adequate water supply is one reason the San Diego City Council is looking at the costly and controversial option of turning wastewater into drinking water.

Up and down the California coast, water officials also are considering desalination.

Populations Soar. The U.S. population has nearly doubled since 1950 and California's has more than tripled. San Diego County's has grown even faster, expanding nearly six-fold during that period.

Sources: U.S. Census Bureau, California Department of Finance.

Union-Tribune

Potential Pitfalls

Despite wide recognition of population growth in the United States and its ecological consequences, there’s no universally accepted estimate of how many people the nation can accommodate.

“It’s really not a scientific question,” said Jim Baird, director of sustainability education at the Izaak Walton League of America, a national conservation group based in Gaithersburg , Md.

“The number of people the U.S. can ‘hold’ is ultimately a question of balancing quality and quantity,” he said. “It is a choice—or many choices —based on values rather than a formula. Our numbers impact the land and its resources, but so does the way we choose to live.”

Doomsayers have long predicted that the world’s use of raw products will outstrip its resources and lead to massive human suffering.

That doctrine was popularized in the late 1960s by Paul Ehrlich, a Stanford University professor famous for his books on the ecological dangers of the population boom. At the time—the start of the modern environmental movement—such thinking was in vogue among conservationists and others.

“No substantial benefits will result from further growth of the nation’s population, rather... the gradual stabilization of our population through voluntary means would contribute significantly to the nation’s ability to solve its problems,” John D. Rockefeller III wrote to President Nixon and Congress in a landmark 1972 report by the Commission on Population Growth and the American Future.

Since then, the nation has grown by roughly 100 million people. However, technological advances that help clean the air, conserve water and grow more food on less farmland have helped to mitigate or delay predicted population-induced disasters.

Ehrlich’s recent writings express doubt that the United States or the world is making progress on population challenges.

“We are losing the struggle to create a sustainable society,” he wrote in a 2003 article in the journal Conservation Biology.

Immigration Politics

Environmental groups continue to discuss overpopulation in stark terms, but such talk is mostly reserved for the international scene. Focusing domestically would be to ignore the economic disparities among countries that spur people to immigrate to the United States , they said.

Last year, one of every five immigrants worldwide lived in the United States , according to a May report by the United Nations.

The National Audubon Society supports international family planning while taking no position on U.S. immigration. Greenpeace and the Natural Resources Defense Council largely stay out of domestic immigration issues, though neither returned calls to explain why.

(Interview requests also were made to the offices of Sens. Barbara Boxer and Dianne Feinstein and San Diego Reps. Susan Davis and Bob Filner. Aides for each Democrat declined to comment or said their bosses weren’t available last week.)

At the San Diego chapter of the Sierra Club, coordinator Cheryl Reiff said immigration politics “become a huge waste of time because you end up battling people who you are really on the same side with.”

Besides, sorting out the ecological costs and benefits of immigration and population growth can be enormously complex. That has led some environmentalists to say their groups should stick with core missions such as saving species, curbing pollution and preserving open space.

Sensitivities

Then there are the racial and cultural sensitivities inherent in discussions of immigration and population control.

For example, aggressively advocating birth control or abortion rights in the United States  could alienate church groups that are becoming important allies with conservationists. Such partnerships are growing as an increasing number of faith groups, including evangelical Christians, view conservation as a moral issue.

The U.S.  population grew by 14.9 million between April 2000 and July 2005. Immigration accounted for more than 42 percent of that total, according to Census Bureau data.

Immigrants also play a key role in population growth once they arrive in the United States .

A 2005 bureau report found that there was an annual average of 84 births per 1,000 foreign-born women of childbearing age in the U.S. , compared with 57 births per 1,000 native U.S.  women.

Latinos have the nation’s highest birthrates among major population groups, the report showed.

“It’s...a very touchy issue to deal with,” said  Mel Hinton, president of the San Diego Audubon Society. “You are asking people to limit their reproductive rights or goals or desires, and that is very difficult.”

Also controversial is the issue of illegal immigration.

Recently, the U.S. government and the Pew Hispanic Center estimated that the United States has 12 million unauthorized immigrants. About 3 million of them, mostly from Mexico , live in California .

Immigration issues have proved highly divisive for the Sierra Club in recent years.

In 2004, for example, the organization was deeply split by three candidates who ran for board positions on platforms to limit immigration. Some of the group’s members saw it as a racist campaign, and none of the candidates won.

But the results didn’t quell the debate among conservationists such as Alan Kuper of Cleveland Heights , Ohio , a veteran of the Sierra Club’s population controversies.

These days, Kuper operates a nonprofit outfit that tracks how congressional members vote on immigration and population issues along with more traditional conservation topics. His group is called CUSP, for Comprehensive US Sustainable Population.

“What we are trying to tell the environmental establishment is that they really can’t” ignore the U.S. population trends, Kuper said. “We have to talk about the physical and biological and resource limits that nature imposed on us.”