To environmentalists worried about population growth, people are people.
Even if they do their best to live lightly on the land, their rising numbers are a growing burden on Earth's resources. And whether they sing the "The Star-Spangled Banner" in English or in Spanish really doesn't matter.
As politicians and the public heatedly debate immigration, so, too, are environmental activists.
The flow of people into the United States is troubling some environmentalists for two reasons. First, more Americans means more people living in one of the world's most resource-consuming cultures. Second, there's new evidence that Hispanic women who move to the US have more children than if they stayed put.
"We've got to talk about these issues - population, birth rates, immigration," says Paul Watson, founder of the Sea Shepherd Conservation Society, which confronts whalers, seal hunters, and those who poach wildlife in the Galapagos Islands. "Immigration is one of the leading contributors to population growth. All we're saying is, those numbers should be reduced to achieve population stabilization."
Mr. Watson also was a Sierra Club board member.Last month, he resigned in protest just before his three-year term ended because he thinks the organization ignores immigration as a major factor in population growth.
Beneath the dispute is a political subtext. Environmentalists generally see themselves as political progressives; they don't want to be bedfellows with anti-immigrant activists sometimes labeled as xenophobic or racist. Very few greens raise a supportive fist when they see "Stop the Invasion" billboards sprouting from California to Florida. For the most part, they skirt the issue.
"The leadership and the membership have said we want to be neutral on this," says Eric Antebi, national press secretary for the Sierra Club in San Francisco, one of the largest and oldest grassroots environmental groups in the country. It's a global issue, says Mr. Antebi, caused by environmental degradation and poverty that need to be solved so people won't have to look elsewhere for a better life. Other large environmental groups take the same position.
Yet the US population is far from stabilized, and immigrants (legal and illegal) are one of the main reasons. There are about 11 million illegal immigrants in the US today, 57 percent from Mexico, and another 24 percent from other Latin American countries, according to the Pew Hispanic Center. Of the US foreign-born population, nearly 30 percent is illegal, according to Pew.
The US Census Bureau this week reported that Hispanics - the largest minority at 42.7 million - are the nation's fastest-growing group. They are 14.3 percent of the overall population, but between July 2004 and July 2005, they accounted for 49 percent of US population growth. Of the increase of 1.3 million Hispanics, the Census Bureau reported, 800,000 was because of natural increase (births minus deaths), and 500,000 was due to immigration.
"The Hispanic population in 2005 was much younger, with a median age of 27.2 years compared to the population as a whole at 36.2 years. About a third of the Hispanic population was under 18, compared with one-fourth of the total population," according to the Census Bureau report. That means such younger people are just entering (or will remain longer in) the years in which they have children of their own.
Steven Camarota, director of research at the Center for Immigration Studies in Washington, finds that once women emigrate to the US, most tend to have more children than they would have in their home countries. "Among Mexican immigrants in the United States fertility averages 3.5 children per woman compared to 2.4 children per woman in Mexico," he wrote in a study last October. And the same is true among Chinese immigrants. Fertility is 2.3 in the US compared with 1.7 in China. However, typically these high fertility rates decline in the successive generations as immigrants assimilate into America.
"New immigrants (legal and illegal) plus births to immigrants add some 2.3 million people to the United States each year," Camarota writes, "accounting for most of the nation's population increase."
Over the past 60 to 70 years, US population doubled to nearly 300 million. If current birth and immigration rates were to remain unchanged for another 60 to 70 years, US population again would double to some 600 million people - the equivalent of adding another state the size of California every decade.
"You just can't deal with that issue without dealing with immigration," says Bill Elder of Issaquah, Wash., a former Sierra Club activist now organizing prominent conservation leaders to focus on population.
Though China and India have much larger populations, the US has the highest population growth rate of all developed countries. Also, experts say, Americans on average have greater environmental impact. The equation for this is I = PAT (Impact = Population x Affluence x Technology), with such impact being the main thing determining whether an area's "carrying capacity" has been exceeded.
Harvard University ecologist Edward Wilson figures that the "ecological footprint" - which he defined in a Scientific American article in 2002 as "the average amount of productive land and shallow sea appropriated by each person in bits and pieces from around the world for food, water, housing, energy, transportation, commerce, and waste absorption" - is about 5 acres per person worldwide. In the US, each individual's ecological footprint is about 24 acres, according to Dr. Wilson.
"Our responsibility for pollution and resource use is all out of proportion to our numbers," says Alan Kuper, a retired physicist in Cleveland and founder of Comprehensive US Sustainable Population. The group publishes a "Congressional Environmental Scorecard" on lawmakers' votes about conservation, consumption, and population, including immigration. "It's not a matter of where or how people come, it's the growth that we have to be concerned with," says Dr. Kuper. "If you're going to be an environmentalist, you have to be concerned about the numbers as well as the usual issues - public lands, energy, pollution, and so forth - because the numbers will just wipe you out."